Tracking wait event for latches

diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 8ca1c1c..954a166 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -496,7 +496,7 @@ pgfdw_get_result(PGconn *conn, const char *query)
 			wc = WaitLatchOrSocket(MyLatch,
 								   WL_LATCH_SET | WL_SOCKET_READABLE,
 								   PQsocket(conn),
-								   -1L);
+								   -1L, EVENT_EXTENSION);
 			ResetLatch(MyLatch);
 
 			CHECK_FOR_INTERRUPTS();
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 1c283a0..15e58a6 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -679,6 +679,16 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
           buffer in question.
          </para>
         </listitem>
+        <listitem>
+         <para>
+          <literal>EventSet</>: The server process is waiting on a socket
+          or a timer. This wait happens in a latch, an inter-process facility
+          using boolean variables letting a process sleep until it is set.
+          Latches support several type of operations, like postmaster death
+          handling, timeout and socket activity lookup, and are a useful
+          replacement for <function>sleep</> where signal handling matters.
+         </para>
+        </listitem>
        </itemizedlist>
       </entry>
      </row>
@@ -1081,6 +1091,139 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
          <entry><literal>BufferPin</></entry>
          <entry>Waiting to acquire a pin on a buffer.</entry>
         </row>
+        <row>
+         <entry morerows="30"><literal>EventSet</></entry>
+         <entry><literal>ArchiverMain</></entry>
+         <entry>Waiting in main loop of the archiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>AutoVacuumMain</></entry>
+         <entry>Waiting in main loop of autovacuum launcher process.</entry>
+        </row>
+        <row>
+         <entry><literal>BaseBackupThrottle</></entry>
+         <entry>Waiting during base backup when throttling activity.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWorkerStartup</></entry>
+         <entry>Waiting for background worker to start up.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWorkerShutdown</></entry>
+         <entry>Waiting for background worker to shut down.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterMain</></entry>
+         <entry>Waiting in main loop of background writer process background worker.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterHibernate</></entry>
+         <entry>Waiting in background writer process, hibernating.</entry>
+        </row>
+        <row>
+         <entry><literal>CheckpointerMain</></entry>
+         <entry>Waiting in main loop of checkpointer process.</entry>
+        </row>
+        <row>
+         <entry><literal>ExecuteGather</></entry>
+         <entry>Waiting for activity from child process when executing <literal>Gather</> node.</entry>
+        </row>
+        <row>
+         <entry><literal>Extension</></entry>
+         <entry>Waiting in the code path of an extension, should be used by custom plugins and modules</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueuePutMessage</></entry>
+         <entry>Waiting to put new message in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueSend</></entry>
+         <entry>Waiting to send bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueReceive</></entry>
+         <entry>Waiting to receive bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueInternal</></entry>
+         <entry>Waiting for other process to be attached in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>ParallelFinish</></entry>
+         <entry>Waiting for parallel workers to finish computing.</entry>
+        </row>
+        <row>
+         <entry><literal>PgSleep</></entry>
+         <entry>Waiting in process that called <function>pg_sleep</>.</entry>
+        </row>
+        <row>
+         <entry><literal>PgStatMain</></entry>
+         <entry>Waiting in main loop of the statistics collector process.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSleep</></entry>
+         <entry>Waiting for a specific lock.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSignal</></entry>
+         <entry>Waiting for signal from another backend.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryApplyDelay</></entry>
+         <entry>Waiting to apply WAL at recovery because it is delayed.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalStream</></entry>
+         <entry>Waiting for WAL from a stram at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalAll</></entry>
+         <entry>Waiting for WAL from any kind of source (local, archive or stream) at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>SecureRead</></entry>
+         <entry>Waiting to read data from a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SecureWrite</></entry>
+         <entry>Waiting to write data to a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SSLOpenServer</></entry>
+         <entry>Waiting for SSL while attempting connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SyncRep</></entry>
+         <entry>Waiting for WAL commit during synchronous replication.</entry>
+        </row>
+        <row>
+         <entry><literal>SysLoggerMain</></entry>
+         <entry>Waiting in main loop of syslogger process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalWriterMain</></entry>
+         <entry>Waiting in main loop of WAL writer process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverWaitStart</></entry>
+         <entry>Waiting for startup process to send initial data for streaming replication.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverMain</></entry>
+         <entry>Waiting in main loop of WAL receiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderMain</></entry>
+         <entry>Waiting in main loop of WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWaitForWAL</></entry>
+         <entry>Waiting for WAL to be flushed in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWriteData</></entry>
+         <entry>Waiting for any activity when processing replies from WAL receiver in WAL sender process.</entry>
+        </row>
       </tbody>
      </tgroup>
     </table>
diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c
index a303fca..88b659b 100644
--- a/src/backend/access/transam/parallel.c
+++ b/src/backend/access/transam/parallel.c
@@ -541,7 +541,8 @@ WaitForParallelWorkersToFinish(ParallelContext *pcxt)
 		if (!anyone_alive)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1,
+				  EVENT_PARALLEL_WAIT_FINISH);
 		ResetLatch(&MyProc->procLatch);
 	}
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index f13f9c1..19d9977 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5756,7 +5756,8 @@ recoveryApplyDelay(XLogReaderState *record)
 
 		WaitLatch(&XLogCtl->recoveryWakeupLatch,
 				  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-				  secs * 1000L + microsecs / 1000);
+				  secs * 1000L + microsecs / 1000,
+				  EVENT_RECOVERY_APPLY_DELAY);
 	}
 	return true;
 }
@@ -11294,7 +11295,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 
 						WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								  wait_time);
+							 wait_time, EVENT_RECOVERY_WAL_STREAM);
 						ResetLatch(&XLogCtl->recoveryWakeupLatch);
 						now = GetCurrentTimestamp();
 					}
@@ -11457,7 +11458,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					 */
 					WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							  5000L);
+							  5000L, EVENT_RECOVERY_WAL_ALL);
 					ResetLatch(&XLogCtl->recoveryWakeupLatch);
 					break;
 				}
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 438d1b2..d8fe2a5 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -387,7 +387,7 @@ gather_readnext(GatherState *gatherstate)
 				return NULL;
 
 			/* Nothing to do except wait for developments. */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_EXECUTE_GATHER);
 			ResetLatch(MyLatch);
 			nvisited = 0;
 		}
diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
index f6adb15..759b337 100644
--- a/src/backend/libpq/be-secure-openssl.c
+++ b/src/backend/libpq/be-secure-openssl.c
@@ -418,7 +418,8 @@ aloop:
 				else
 					waitfor = WL_SOCKET_WRITEABLE;
 
-				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0);
+				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0,
+								  EVENT_SSL_OPEN_SERVER);
 				goto aloop;
 			case SSL_ERROR_SYSCALL:
 				if (r < 0)
diff --git a/src/backend/libpq/be-secure.c b/src/backend/libpq/be-secure.c
index cdd07d5..5880818 100644
--- a/src/backend/libpq/be-secure.c
+++ b/src/backend/libpq/be-secure.c
@@ -146,7 +146,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 EVENT_SECURE_READ);
 
 		/*
 		 * If the postmaster has died, it's not safe to continue running,
@@ -247,7 +248,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 EVENT_SECURE_WRITE);
 
 		/* See comments in secure_read. */
 		if (event.events & WL_POSTMASTER_DEATH)
diff --git a/src/backend/libpq/pqmq.c b/src/backend/libpq/pqmq.c
index 921242f..6c39e51 100644
--- a/src/backend/libpq/pqmq.c
+++ b/src/backend/libpq/pqmq.c
@@ -171,7 +171,7 @@ mq_putmessage(char msgtype, const char *s, size_t len)
 		if (result != SHM_MQ_WOULD_BLOCK)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0, EVENT_MQ_PUT_MESSAGE);
 		ResetLatch(&MyProc->procLatch);
 		CHECK_FOR_INTERRUPTS();
 	}
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 3768f50..bb80c11 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -600,7 +600,8 @@ AutoVacLauncherMain(int argc, char *argv[])
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L));
+					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L),
+					   EVENT_AUTOVACUUM_MAIN);
 
 		ResetLatch(MyLatch);
 
diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c
index 382edad..1d41b00 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -969,7 +969,8 @@ WaitForBackgroundWorkerStartup(BackgroundWorkerHandle *handle, pid_t *pidp)
 			break;
 
 		rc = WaitLatch(MyLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   EVENT_BGWORKER_STARTUP);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
@@ -1008,7 +1009,8 @@ WaitForBackgroundWorkerShutdown(BackgroundWorkerHandle *handle)
 			return status;
 
 		rc = WaitLatch(&MyProc->procLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   EVENT_BGWORKER_SHUTDOWN);
 
 		if (rc & WL_POSTMASTER_DEATH)
 			return BGWH_POSTMASTER_DIED;
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index 00f03d8..1c135de 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -347,7 +347,8 @@ BackgroundWriterMain(void)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   BgWriterDelay /* ms */ );
+					   BgWriterDelay /* ms */,
+					   EVENT_BGWRITER_MAIN);
 
 		/*
 		 * If no latch event and BgBufferSync says nothing's happening, extend
@@ -374,7 +375,8 @@ BackgroundWriterMain(void)
 			/* Sleep ... */
 			rc = WaitLatch(MyLatch,
 						   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-						   BgWriterDelay * HIBERNATE_FACTOR);
+						   BgWriterDelay * HIBERNATE_FACTOR,
+						   EVENT_BGWRITER_HIBERNATE);
 			/* Reset the notification request in case we timed out */
 			StrategyNotifyBgWriter(-1);
 		}
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index 8d4b353..60bab87 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -558,7 +558,8 @@ CheckpointerMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout * 1000L /* convert to ms */ );
+					   cur_timeout * 1000L /* convert to ms */,
+					   EVENT_CHECKPOINTER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 1aa6466..156fff7 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -390,7 +390,7 @@ pgarch_MainLoop(void)
 
 				rc = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							   timeout * 1000L);
+							 timeout * 1000L, EVENT_ARCHIVER_MAIN);
 				if (rc & WL_TIMEOUT)
 					wakened = true;
 			}
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 8fa9edb..9dd49ec 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -3152,6 +3152,9 @@ pgstat_get_wait_event_type(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_type = "BufferPin";
 			break;
+		case WAIT_EVENT_SET:
+			event_type = "EventSet";
+			break;
 		default:
 			event_type = "???";
 			break;
@@ -3193,6 +3196,9 @@ pgstat_get_wait_event(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_name = "BufferPin";
 			break;
+		case WAIT_EVENT_SET:
+			event_name = GetEventIdentifier(eventId);
+			break;
 		default:
 			event_name = "unknown wait event";
 			break;
@@ -3682,7 +3688,7 @@ PgstatCollectorMain(int argc, char *argv[])
 		wr = WaitLatchOrSocket(MyLatch,
 					 WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE,
 							   pgStatSock,
-							   -1L);
+							   -1L, EVENT_PGSTAT_MAIN);
 #else
 
 		/*
@@ -3698,7 +3704,8 @@ PgstatCollectorMain(int argc, char *argv[])
 		wr = WaitLatchOrSocket(MyLatch,
 		WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE | WL_TIMEOUT,
 							   pgStatSock,
-							   2 * 1000L /* msec */ );
+							   2 * 1000L /* msec */,
+							   EVENT_PGSTAT_MAIN);
 #endif
 
 		/*
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index e7e488a..c147fd1 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -424,7 +424,8 @@ SysLoggerMain(int argc, char *argv[])
 		rc = WaitLatchOrSocket(MyLatch,
 							   WL_LATCH_SET | WL_SOCKET_READABLE | cur_flags,
 							   syslogPipe[0],
-							   cur_timeout);
+							   cur_timeout,
+							   EVENT_SYSLOGGER_MAIN);
 
 		if (rc & WL_SOCKET_READABLE)
 		{
@@ -475,7 +476,8 @@ SysLoggerMain(int argc, char *argv[])
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | cur_flags,
-						 cur_timeout);
+						 cur_timeout,
+						 EVENT_SYSLOGGER_MAIN);
 
 		EnterCriticalSection(&sysloggerSection);
 #endif   /* WIN32 */
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index 228190a..781e7b0 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -292,7 +292,8 @@ WalWriterMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout);
+					   cur_timeout,
+					   EVENT_WALWRITER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index da9b7a6..308220f 100644
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -1286,7 +1286,8 @@ throttle(size_t increment)
 		 */
 		wait_result = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								(long) (sleep / 1000));
+								(long) (sleep / 1000),
+								EVENT_BASEBACKUP_THROTTLE);
 
 		if (wait_result & WL_LATCH_SET)
 			CHECK_FOR_INTERRUPTS();
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index 67249d8..9b997c8 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -265,7 +265,8 @@ SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
 		 * Wait on latch.  Any condition that should wake us up will set the
 		 * latch, so no need for timeout.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1);
+		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1,
+				  EVENT_SYNC_REP);
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 413ee3a..dfd7d37 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -486,7 +486,8 @@ WalReceiverMain(void)
 								   WL_POSTMASTER_DEATH | WL_SOCKET_READABLE |
 									   WL_TIMEOUT | WL_LATCH_SET,
 									   wait_fd,
-									   NAPTIME_PER_CYCLE);
+									   NAPTIME_PER_CYCLE,
+									   EVENT_WAL_RECEIVER_MAIN);
 				if (rc & WL_LATCH_SET)
 				{
 					ResetLatch(&walrcv->latch);
@@ -685,7 +686,8 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 		}
 		SpinLockRelease(&walrcv->mutex);
 
-		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+				  EVENT_WAL_RECEIVER_WAIT_START);
 	}
 
 	if (update_process_title)
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index a0dba19..b612395 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -1146,7 +1146,8 @@ WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid,
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  EVENT_WAL_SENDER_WRITE_DATA);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1272,7 +1273,8 @@ WalSndWaitForWal(XLogRecPtr loc)
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  EVENT_WAL_SENDER_WAIT_WAL);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1923,7 +1925,8 @@ WalSndLoop(WalSndSendDataCallback send_data)
 
 			/* Sleep until something happens or we time out */
 			WaitLatchOrSocket(MyLatch, wakeEvents,
-							  MyProcPort->sock, sleeptime);
+							  MyProcPort->sock, sleeptime,
+							  EVENT_WAL_SENDER_LOOP);
 		}
 	}
 	return;
diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c
index 9def8a1..435f183 100644
--- a/src/backend/storage/ipc/latch.c
+++ b/src/backend/storage/ipc/latch.c
@@ -55,6 +55,7 @@
 #endif
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "portability/instr_time.h"
 #include "postmaster/postmaster.h"
 #include "storage/barrier.h"
@@ -297,9 +298,11 @@ DisownLatch(volatile Latch *latch)
  * we return all of them in one call, but we will return at least one.
  */
 int
-WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
+WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+		  EventIdentifier eventId)
 {
-	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout);
+	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout,
+							 eventId);
 }
 
 /*
@@ -316,7 +319,7 @@ WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
  */
 int
 WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
-				  long timeout)
+				  long timeout, EventIdentifier eventId)
 {
 	int			ret = 0;
 	int			rc;
@@ -344,7 +347,7 @@ WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
 		AddWaitEventToSet(set, ev, sock, NULL, NULL);
 	}
 
-	rc = WaitEventSetWait(set, timeout, &event, 1);
+	rc = WaitEventSetWait(set, timeout, &event, 1, eventId);
 
 	if (rc == 0)
 		ret |= WL_TIMEOUT;
@@ -863,7 +866,8 @@ WaitEventAdjustWin32(WaitEventSet *set, WaitEvent *event)
  */
 int
 WaitEventSetWait(WaitEventSet *set, long timeout,
-				 WaitEvent *occurred_events, int nevents)
+				 WaitEvent *occurred_events, int nevents,
+				 EventIdentifier eventId)
 {
 	int			returned_events = 0;
 	instr_time	start_time;
@@ -872,6 +876,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 
 	Assert(nevents > 0);
 
+	pgstat_report_wait_start(WAIT_EVENT_SET, (uint16) eventId);
+
 	/*
 	 * Initialize timeout if requested.  We must record the current time so
 	 * that we can determine the remaining timeout if interrupted.
@@ -960,6 +966,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 	waiting = false;
 #endif
 
+	pgstat_report_wait_end();
+
 	return returned_events;
 }
 
@@ -1491,6 +1499,125 @@ WaitEventSetWaitBlock(WaitEventSet *set, int cur_timeout,
 }
 #endif
 
+
+/*
+ * Return an identifier for a Latch depending on an event for statistics
+ * collector.
+ */
+const char *
+GetEventIdentifier(uint16 eventId)
+{
+	const char *res;
+
+	switch (eventId)
+	{
+		case EVENT_ARCHIVER_MAIN:
+			res = "ArchiverMain";
+			break;
+		case EVENT_AUTOVACUUM_MAIN:
+			res = "AutoVacuumMain";
+			break;
+		case EVENT_BASEBACKUP_THROTTLE:
+			res = "BaseBackupThrottle";
+			break;
+		case EVENT_BGWORKER_STARTUP:
+			res = "BgWorkerStartup";
+			break;
+		case EVENT_BGWORKER_SHUTDOWN:
+			res = "BgWorkerShutdown";
+			break;
+		case EVENT_BGWRITER_MAIN:
+			res = "BgWriterMain";
+			break;
+		case EVENT_BGWRITER_HIBERNATE:
+			res = "BgWriterHibernate";
+			break;
+		case EVENT_CHECKPOINTER_MAIN:
+			res = "CheckpointerMain";
+			break;
+		case EVENT_EXECUTE_GATHER:
+			res = "ExecuteGather";
+			break;
+		case EVENT_EXTENSION:
+			res = "Extension";
+			break;
+		case EVENT_MQ_PUT_MESSAGE:
+			res = "MessageQueuePutMessage";
+			break;
+		case EVENT_MQ_SEND_BYTES:
+			res = "MessageQueueSend";
+			break;
+		case EVENT_MQ_RECEIVE_BYTES:
+			res = "MessageQueueReceive";
+			break;
+		case EVENT_MQ_WAIT_INTERNAL:
+			res = "MessageQueueInternal";
+			break;
+		case EVENT_PARALLEL_WAIT_FINISH:
+			res = "ParallelFinish";
+			break;
+		case EVENT_PG_SLEEP:
+			res = "PgSleep";
+			break;
+		case EVENT_PGSTAT_MAIN:
+			res = "PgStatMain";
+			break;
+		case EVENT_PROC_SLEEP:
+			res = "ProcSleep";
+			break;
+		case EVENT_PROC_SIGNAL:
+			res = "ProcSignal";
+			break;
+		case EVENT_RECOVERY_APPLY_DELAY:
+			res = "RecoveryApplyDelay";
+			break;
+		case EVENT_RECOVERY_WAL_STREAM:
+			res = "RecoveryWalStream";
+			break;
+		case EVENT_RECOVERY_WAL_ALL:
+			res = "RecoveryWalAll";
+			break;
+		case EVENT_SECURE_READ:
+			res = "SecureRead";
+			break;
+		case EVENT_SECURE_WRITE:
+			res = "SecureWrite";
+			break;
+		case EVENT_SSL_OPEN_SERVER:
+			res = "SSLOpenServer";
+			break;
+		case EVENT_SYNC_REP:
+			res = "SyncRep";
+			break;
+		case EVENT_SYSLOGGER_MAIN:
+			res = "SysLoggerMain";
+			break;
+		case EVENT_WALWRITER_MAIN:
+			res = "WalWriterMain";
+			break;
+		case EVENT_WAL_RECEIVER_WAIT_START:
+			res = "WalSenderWaitStart";
+			break;
+		case EVENT_WAL_RECEIVER_MAIN:
+			res = "WalReceiverMain";
+			break;
+		case EVENT_WAL_SENDER_LOOP:
+			res = "WalSenderMain";
+			break;
+		case EVENT_WAL_SENDER_WAIT_WAL:
+			res = "WalSenderWaitForWAL";
+			break;
+		case EVENT_WAL_SENDER_WRITE_DATA:
+			res = "WalSenderWriteData";
+			break;
+		default:
+			res = "???";
+	}
+
+	return res;
+}
+
+
 /*
  * SetLatch uses SIGUSR1 to wake up the process waiting on the latch.
  *
diff --git a/src/backend/storage/ipc/shm_mq.c b/src/backend/storage/ipc/shm_mq.c
index 5b32782..af5344c 100644
--- a/src/backend/storage/ipc/shm_mq.c
+++ b/src/backend/storage/ipc/shm_mq.c
@@ -894,7 +894,7 @@ shm_mq_send_bytes(shm_mq_handle *mqh, Size nbytes, const void *data,
 			 * at top of loop, because setting an already-set latch is much
 			 * cheaper than setting one that has been reset.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_MQ_SEND_BYTES);
 
 			/* Reset the latch so we don't spin. */
 			ResetLatch(MyLatch);
@@ -991,7 +991,7 @@ shm_mq_receive_bytes(shm_mq *mq, Size bytes_needed, bool nowait,
 		 * loop, because setting an already-set latch is much cheaper than
 		 * setting one that has been reset.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_MQ_RECEIVE_BYTES);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
@@ -1090,7 +1090,7 @@ shm_mq_wait_internal(volatile shm_mq *mq, PGPROC *volatile * ptr,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_MQ_WAIT_INTERNAL);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 9a758bd..2ed3f41 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -1216,7 +1216,7 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
 		}
 		else
 		{
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_PROC_SLEEP);
 			ResetLatch(MyLatch);
 			/* check for deadlocks first, as that's probably log-worthy */
 			if (got_deadlock_timeout)
@@ -1728,7 +1728,7 @@ CheckDeadLockAlert(void)
 void
 ProcWaitForSignal(void)
 {
-	WaitLatch(MyLatch, WL_LATCH_SET, 0);
+	WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_PROC_SIGNAL);
 	ResetLatch(MyLatch);
 	CHECK_FOR_INTERRUPTS();
 }
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 5e705e9..ea88c87 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -560,7 +560,7 @@ pg_sleep(PG_FUNCTION_ARGS)
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | WL_TIMEOUT,
-						 delay_ms);
+						 delay_ms, EVENT_PG_SLEEP);
 		ResetLatch(MyLatch);
 	}
 
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index dc3320d..bca16e4 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -721,7 +721,8 @@ typedef enum WaitClass
 	WAIT_LWLOCK_NAMED,
 	WAIT_LWLOCK_TRANCHE,
 	WAIT_LOCK,
-	WAIT_BUFFER_PIN
+	WAIT_BUFFER_PIN,
+	WAIT_EVENT_SET
 }	WaitClass;
 
 
diff --git a/src/include/storage/latch.h b/src/include/storage/latch.h
index 5179ecc..41dc553 100644
--- a/src/include/storage/latch.h
+++ b/src/include/storage/latch.h
@@ -135,6 +135,47 @@ typedef struct WaitEvent
 	void	   *user_data;		/* pointer provided in AddWaitEventToSet */
 } WaitEvent;
 
+/*
+ * List of latch identifiers used when reporting activity to statistics
+ * collector.
+ */
+typedef enum EventIdentifier
+{
+	EVENT_ARCHIVER_MAIN,
+	EVENT_AUTOVACUUM_MAIN,
+	EVENT_BASEBACKUP_THROTTLE,
+	EVENT_BGWORKER_STARTUP,
+	EVENT_BGWORKER_SHUTDOWN,
+	EVENT_BGWRITER_MAIN,
+	EVENT_BGWRITER_HIBERNATE,
+	EVENT_CHECKPOINTER_MAIN,
+	EVENT_EXECUTE_GATHER,
+	EVENT_EXTENSION,
+	EVENT_MQ_PUT_MESSAGE,
+	EVENT_MQ_SEND_BYTES,
+	EVENT_MQ_RECEIVE_BYTES,
+	EVENT_MQ_WAIT_INTERNAL,
+	EVENT_PARALLEL_WAIT_FINISH,
+	EVENT_PGSTAT_MAIN,
+	EVENT_PROC_SLEEP,
+	EVENT_PROC_SIGNAL,
+	EVENT_PG_SLEEP,
+	EVENT_SECURE_READ,
+	EVENT_SECURE_WRITE,
+	EVENT_SSL_OPEN_SERVER,
+	EVENT_SYNC_REP,
+	EVENT_SYSLOGGER_MAIN,
+	EVENT_RECOVERY_APPLY_DELAY,
+	EVENT_RECOVERY_WAL_ALL,
+	EVENT_RECOVERY_WAL_STREAM,
+	EVENT_WAL_RECEIVER_WAIT_START,
+	EVENT_WAL_RECEIVER_MAIN,
+	EVENT_WAL_SENDER_WRITE_DATA,
+	EVENT_WAL_SENDER_LOOP,
+	EVENT_WAL_SENDER_WAIT_WAL,
+	EVENT_WALWRITER_MAIN
+} EventIdentifier;
+
 /* forward declaration to avoid exposing latch.c implementation details */
 typedef struct WaitEventSet WaitEventSet;
 
@@ -155,10 +196,14 @@ extern int AddWaitEventToSet(WaitEventSet *set, uint32 events, pgsocket fd,
 				  Latch *latch, void *user_data);
 extern void ModifyWaitEvent(WaitEventSet *set, int pos, uint32 events, Latch *latch);
 
-extern int	WaitEventSetWait(WaitEventSet *set, long timeout, WaitEvent *occurred_events, int nevents);
-extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout);
+extern int	WaitEventSetWait(WaitEventSet *set, long timeout,
+				  WaitEvent *occurred_events, int nevents,
+				  EventIdentifier eventId);
+extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+				  EventIdentifier eventId);
 extern int WaitLatchOrSocket(volatile Latch *latch, int wakeEvents,
-				  pgsocket sock, long timeout);
+				  pgsocket sock, long timeout, EventIdentifier eventId);
+extern const char *GetEventIdentifier(uint16 eventId);
 
 /*
  * Unix implementation uses SIGUSR1 for inter-process signaling.
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 143df4e..d32e42e 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -279,7 +279,7 @@ wait_for_workers_to_become_ready(worker_state *wstate,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_EXTENSION);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/test/modules/test_shm_mq/test.c b/src/test/modules/test_shm_mq/test.c
index dd34bc7..caddf83 100644
--- a/src/test/modules/test_shm_mq/test.c
+++ b/src/test/modules/test_shm_mq/test.c
@@ -230,7 +230,7 @@ test_shm_mq_pipelined(PG_FUNCTION_ARGS)
 			 * have read or written data and therefore there may now be work
 			 * for us to do.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_EXTENSION);
 			ResetLatch(MyLatch);
 			CHECK_FOR_INTERRUPTS();
 		}
diff --git a/src/test/modules/worker_spi/worker_spi.c b/src/test/modules/worker_spi/worker_spi.c
index 314e371..bb0d7ff 100644
--- a/src/test/modules/worker_spi/worker_spi.c
+++ b/src/test/modules/worker_spi/worker_spi.c
@@ -227,7 +227,8 @@ worker_spi_main(Datum main_arg)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   worker_spi_naptime * 1000L);
+					   worker_spi_naptime * 1000L,
+					   EVENT_EXTENSION);
 		ResetLatch(MyLatch);
 
 		/* emergency bailout if postmaster has died */

diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 8ca1c1c..954a166 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -496,7 +496,7 @@ pgfdw_get_result(PGconn *conn, const char *query)
 			wc = WaitLatchOrSocket(MyLatch,
 								   WL_LATCH_SET | WL_SOCKET_READABLE,
 								   PQsocket(conn),
-								   -1L);
+								   -1L, EVENT_EXTENSION);
 			ResetLatch(MyLatch);
 
 			CHECK_FOR_INTERRUPTS();
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 0776428..a14abe4 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -679,6 +679,16 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
           buffer in question.
          </para>
         </listitem>
+        <listitem>
+         <para>
+          <literal>EventSet</>: The server process is waiting on a socket
+          or a timer. This wait happens in a latch, an inter-process facility
+          using boolean variables letting a process sleep until it is set.
+          Latches support several type of operations, like postmaster death
+          handling, timeout and socket activity lookup, and are a useful
+          replacement for <function>sleep</> where signal handling matters.
+         </para>
+        </listitem>
        </itemizedlist>
       </entry>
      </row>
@@ -1085,6 +1095,139 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
          <entry><literal>BufferPin</></entry>
          <entry>Waiting to acquire a pin on a buffer.</entry>
         </row>
+        <row>
+         <entry morerows="32"><literal>EventSet</></entry>
+         <entry><literal>ArchiverMain</></entry>
+         <entry>Waiting in main loop of the archiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>AutoVacuumMain</></entry>
+         <entry>Waiting in main loop of autovacuum launcher process.</entry>
+        </row>
+        <row>
+         <entry><literal>BaseBackupThrottle</></entry>
+         <entry>Waiting during base backup when throttling activity.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWorkerStartup</></entry>
+         <entry>Waiting for background worker to start up.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWorkerShutdown</></entry>
+         <entry>Waiting for background worker to shut down.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterMain</></entry>
+         <entry>Waiting in main loop of background writer process background worker.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterHibernate</></entry>
+         <entry>Waiting in background writer process, hibernating.</entry>
+        </row>
+        <row>
+         <entry><literal>CheckpointerMain</></entry>
+         <entry>Waiting in main loop of checkpointer process.</entry>
+        </row>
+        <row>
+         <entry><literal>ExecuteGather</></entry>
+         <entry>Waiting for activity from child process when executing <literal>Gather</> node.</entry>
+        </row>
+        <row>
+         <entry><literal>Extension</></entry>
+         <entry>Waiting in the code path of an extension, should be used by custom plugins and modules</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueuePutMessage</></entry>
+         <entry>Waiting to put new message in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueSend</></entry>
+         <entry>Waiting to send bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueReceive</></entry>
+         <entry>Waiting to receive bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueInternal</></entry>
+         <entry>Waiting for other process to be attached in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>ParallelFinish</></entry>
+         <entry>Waiting for parallel workers to finish computing.</entry>
+        </row>
+        <row>
+         <entry><literal>PgSleep</></entry>
+         <entry>Waiting in process that called <function>pg_sleep</>.</entry>
+        </row>
+        <row>
+         <entry><literal>PgStatMain</></entry>
+         <entry>Waiting in main loop of the statistics collector process.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSleep</></entry>
+         <entry>Waiting for a specific lock.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSignal</></entry>
+         <entry>Waiting for signal from another backend.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryApplyDelay</></entry>
+         <entry>Waiting to apply WAL at recovery because it is delayed.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalStream</></entry>
+         <entry>Waiting for WAL from a stream at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalAll</></entry>
+         <entry>Waiting for WAL from any kind of source (local, archive or stream) at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>SecureRead</></entry>
+         <entry>Waiting to read data from a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SecureWrite</></entry>
+         <entry>Waiting to write data to a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SSLOpenServer</></entry>
+         <entry>Waiting for SSL while attempting connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SyncRep</></entry>
+         <entry>Waiting for WAL commit during synchronous replication.</entry>
+        </row>
+        <row>
+         <entry><literal>SysLoggerMain</></entry>
+         <entry>Waiting in main loop of syslogger process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalWriterMain</></entry>
+         <entry>Waiting in main loop of WAL writer process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverWaitStart</></entry>
+         <entry>Waiting for startup process to send initial data for streaming replication.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverMain</></entry>
+         <entry>Waiting in main loop of WAL receiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderMain</></entry>
+         <entry>Waiting in main loop of WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWaitForWAL</></entry>
+         <entry>Waiting for WAL to be flushed in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWriteData</></entry>
+         <entry>Waiting for any activity when processing replies from WAL receiver in WAL sender process.</entry>
+        </row>
       </tbody>
      </tgroup>
     </table>
diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c
index a47eba6..2495e61 100644
--- a/src/backend/access/transam/parallel.c
+++ b/src/backend/access/transam/parallel.c
@@ -541,7 +541,8 @@ WaitForParallelWorkersToFinish(ParallelContext *pcxt)
 		if (!anyone_alive)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1,
+				  EVENT_PARALLEL_WAIT_FINISH);
 		ResetLatch(&MyProc->procLatch);
 	}
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index f13f9c1..19d9977 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5756,7 +5756,8 @@ recoveryApplyDelay(XLogReaderState *record)
 
 		WaitLatch(&XLogCtl->recoveryWakeupLatch,
 				  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-				  secs * 1000L + microsecs / 1000);
+				  secs * 1000L + microsecs / 1000,
+				  EVENT_RECOVERY_APPLY_DELAY);
 	}
 	return true;
 }
@@ -11294,7 +11295,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 
 						WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								  wait_time);
+							 wait_time, EVENT_RECOVERY_WAL_STREAM);
 						ResetLatch(&XLogCtl->recoveryWakeupLatch);
 						now = GetCurrentTimestamp();
 					}
@@ -11457,7 +11458,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					 */
 					WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							  5000L);
+							  5000L, EVENT_RECOVERY_WAL_ALL);
 					ResetLatch(&XLogCtl->recoveryWakeupLatch);
 					break;
 				}
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 438d1b2..d8fe2a5 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -387,7 +387,7 @@ gather_readnext(GatherState *gatherstate)
 				return NULL;
 
 			/* Nothing to do except wait for developments. */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_EXECUTE_GATHER);
 			ResetLatch(MyLatch);
 			nvisited = 0;
 		}
diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
index f6adb15..759b337 100644
--- a/src/backend/libpq/be-secure-openssl.c
+++ b/src/backend/libpq/be-secure-openssl.c
@@ -418,7 +418,8 @@ aloop:
 				else
 					waitfor = WL_SOCKET_WRITEABLE;
 
-				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0);
+				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0,
+								  EVENT_SSL_OPEN_SERVER);
 				goto aloop;
 			case SSL_ERROR_SYSCALL:
 				if (r < 0)
diff --git a/src/backend/libpq/be-secure.c b/src/backend/libpq/be-secure.c
index cdd07d5..5880818 100644
--- a/src/backend/libpq/be-secure.c
+++ b/src/backend/libpq/be-secure.c
@@ -146,7 +146,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 EVENT_SECURE_READ);
 
 		/*
 		 * If the postmaster has died, it's not safe to continue running,
@@ -247,7 +248,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 EVENT_SECURE_WRITE);
 
 		/* See comments in secure_read. */
 		if (event.events & WL_POSTMASTER_DEATH)
diff --git a/src/backend/libpq/pqmq.c b/src/backend/libpq/pqmq.c
index 921242f..6c39e51 100644
--- a/src/backend/libpq/pqmq.c
+++ b/src/backend/libpq/pqmq.c
@@ -171,7 +171,7 @@ mq_putmessage(char msgtype, const char *s, size_t len)
 		if (result != SHM_MQ_WOULD_BLOCK)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0, EVENT_MQ_PUT_MESSAGE);
 		ResetLatch(&MyProc->procLatch);
 		CHECK_FOR_INTERRUPTS();
 	}
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 3768f50..bb80c11 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -600,7 +600,8 @@ AutoVacLauncherMain(int argc, char *argv[])
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L));
+					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L),
+					   EVENT_AUTOVACUUM_MAIN);
 
 		ResetLatch(MyLatch);
 
diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c
index 382edad..1d41b00 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -969,7 +969,8 @@ WaitForBackgroundWorkerStartup(BackgroundWorkerHandle *handle, pid_t *pidp)
 			break;
 
 		rc = WaitLatch(MyLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   EVENT_BGWORKER_STARTUP);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
@@ -1008,7 +1009,8 @@ WaitForBackgroundWorkerShutdown(BackgroundWorkerHandle *handle)
 			return status;
 
 		rc = WaitLatch(&MyProc->procLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   EVENT_BGWORKER_SHUTDOWN);
 
 		if (rc & WL_POSTMASTER_DEATH)
 			return BGWH_POSTMASTER_DIED;
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index 00f03d8..1c135de 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -347,7 +347,8 @@ BackgroundWriterMain(void)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   BgWriterDelay /* ms */ );
+					   BgWriterDelay /* ms */,
+					   EVENT_BGWRITER_MAIN);
 
 		/*
 		 * If no latch event and BgBufferSync says nothing's happening, extend
@@ -374,7 +375,8 @@ BackgroundWriterMain(void)
 			/* Sleep ... */
 			rc = WaitLatch(MyLatch,
 						   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-						   BgWriterDelay * HIBERNATE_FACTOR);
+						   BgWriterDelay * HIBERNATE_FACTOR,
+						   EVENT_BGWRITER_HIBERNATE);
 			/* Reset the notification request in case we timed out */
 			StrategyNotifyBgWriter(-1);
 		}
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index 8d4b353..60bab87 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -558,7 +558,8 @@ CheckpointerMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout * 1000L /* convert to ms */ );
+					   cur_timeout * 1000L /* convert to ms */,
+					   EVENT_CHECKPOINTER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 1aa6466..156fff7 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -390,7 +390,7 @@ pgarch_MainLoop(void)
 
 				rc = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							   timeout * 1000L);
+							 timeout * 1000L, EVENT_ARCHIVER_MAIN);
 				if (rc & WL_TIMEOUT)
 					wakened = true;
 			}
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 8fa9edb..9dd49ec 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -3152,6 +3152,9 @@ pgstat_get_wait_event_type(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_type = "BufferPin";
 			break;
+		case WAIT_EVENT_SET:
+			event_type = "EventSet";
+			break;
 		default:
 			event_type = "???";
 			break;
@@ -3193,6 +3196,9 @@ pgstat_get_wait_event(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_name = "BufferPin";
 			break;
+		case WAIT_EVENT_SET:
+			event_name = GetEventIdentifier(eventId);
+			break;
 		default:
 			event_name = "unknown wait event";
 			break;
@@ -3682,7 +3688,7 @@ PgstatCollectorMain(int argc, char *argv[])
 		wr = WaitLatchOrSocket(MyLatch,
 					 WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE,
 							   pgStatSock,
-							   -1L);
+							   -1L, EVENT_PGSTAT_MAIN);
 #else
 
 		/*
@@ -3698,7 +3704,8 @@ PgstatCollectorMain(int argc, char *argv[])
 		wr = WaitLatchOrSocket(MyLatch,
 		WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE | WL_TIMEOUT,
 							   pgStatSock,
-							   2 * 1000L /* msec */ );
+							   2 * 1000L /* msec */,
+							   EVENT_PGSTAT_MAIN);
 #endif
 
 		/*
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index e7e488a..c147fd1 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -424,7 +424,8 @@ SysLoggerMain(int argc, char *argv[])
 		rc = WaitLatchOrSocket(MyLatch,
 							   WL_LATCH_SET | WL_SOCKET_READABLE | cur_flags,
 							   syslogPipe[0],
-							   cur_timeout);
+							   cur_timeout,
+							   EVENT_SYSLOGGER_MAIN);
 
 		if (rc & WL_SOCKET_READABLE)
 		{
@@ -475,7 +476,8 @@ SysLoggerMain(int argc, char *argv[])
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | cur_flags,
-						 cur_timeout);
+						 cur_timeout,
+						 EVENT_SYSLOGGER_MAIN);
 
 		EnterCriticalSection(&sysloggerSection);
 #endif   /* WIN32 */
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index 228190a..781e7b0 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -292,7 +292,8 @@ WalWriterMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout);
+					   cur_timeout,
+					   EVENT_WALWRITER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index da9b7a6..308220f 100644
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -1286,7 +1286,8 @@ throttle(size_t increment)
 		 */
 		wait_result = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								(long) (sleep / 1000));
+								(long) (sleep / 1000),
+								EVENT_BASEBACKUP_THROTTLE);
 
 		if (wait_result & WL_LATCH_SET)
 			CHECK_FOR_INTERRUPTS();
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index 67249d8..9b997c8 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -265,7 +265,8 @@ SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
 		 * Wait on latch.  Any condition that should wake us up will set the
 		 * latch, so no need for timeout.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1);
+		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1,
+				  EVENT_SYNC_REP);
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 413ee3a..dfd7d37 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -486,7 +486,8 @@ WalReceiverMain(void)
 								   WL_POSTMASTER_DEATH | WL_SOCKET_READABLE |
 									   WL_TIMEOUT | WL_LATCH_SET,
 									   wait_fd,
-									   NAPTIME_PER_CYCLE);
+									   NAPTIME_PER_CYCLE,
+									   EVENT_WAL_RECEIVER_MAIN);
 				if (rc & WL_LATCH_SET)
 				{
 					ResetLatch(&walrcv->latch);
@@ -685,7 +686,8 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 		}
 		SpinLockRelease(&walrcv->mutex);
 
-		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+				  EVENT_WAL_RECEIVER_WAIT_START);
 	}
 
 	if (update_process_title)
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index a0dba19..b612395 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -1146,7 +1146,8 @@ WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid,
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  EVENT_WAL_SENDER_WRITE_DATA);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1272,7 +1273,8 @@ WalSndWaitForWal(XLogRecPtr loc)
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  EVENT_WAL_SENDER_WAIT_WAL);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1923,7 +1925,8 @@ WalSndLoop(WalSndSendDataCallback send_data)
 
 			/* Sleep until something happens or we time out */
 			WaitLatchOrSocket(MyLatch, wakeEvents,
-							  MyProcPort->sock, sleeptime);
+							  MyProcPort->sock, sleeptime,
+							  EVENT_WAL_SENDER_LOOP);
 		}
 	}
 	return;
diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c
index 9def8a1..435f183 100644
--- a/src/backend/storage/ipc/latch.c
+++ b/src/backend/storage/ipc/latch.c
@@ -55,6 +55,7 @@
 #endif
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "portability/instr_time.h"
 #include "postmaster/postmaster.h"
 #include "storage/barrier.h"
@@ -297,9 +298,11 @@ DisownLatch(volatile Latch *latch)
  * we return all of them in one call, but we will return at least one.
  */
 int
-WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
+WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+		  EventIdentifier eventId)
 {
-	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout);
+	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout,
+							 eventId);
 }
 
 /*
@@ -316,7 +319,7 @@ WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
  */
 int
 WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
-				  long timeout)
+				  long timeout, EventIdentifier eventId)
 {
 	int			ret = 0;
 	int			rc;
@@ -344,7 +347,7 @@ WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
 		AddWaitEventToSet(set, ev, sock, NULL, NULL);
 	}
 
-	rc = WaitEventSetWait(set, timeout, &event, 1);
+	rc = WaitEventSetWait(set, timeout, &event, 1, eventId);
 
 	if (rc == 0)
 		ret |= WL_TIMEOUT;
@@ -863,7 +866,8 @@ WaitEventAdjustWin32(WaitEventSet *set, WaitEvent *event)
  */
 int
 WaitEventSetWait(WaitEventSet *set, long timeout,
-				 WaitEvent *occurred_events, int nevents)
+				 WaitEvent *occurred_events, int nevents,
+				 EventIdentifier eventId)
 {
 	int			returned_events = 0;
 	instr_time	start_time;
@@ -872,6 +876,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 
 	Assert(nevents > 0);
 
+	pgstat_report_wait_start(WAIT_EVENT_SET, (uint16) eventId);
+
 	/*
 	 * Initialize timeout if requested.  We must record the current time so
 	 * that we can determine the remaining timeout if interrupted.
@@ -960,6 +966,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 	waiting = false;
 #endif
 
+	pgstat_report_wait_end();
+
 	return returned_events;
 }
 
@@ -1491,6 +1499,125 @@ WaitEventSetWaitBlock(WaitEventSet *set, int cur_timeout,
 }
 #endif
 
+
+/*
+ * Return an identifier for a Latch depending on an event for statistics
+ * collector.
+ */
+const char *
+GetEventIdentifier(uint16 eventId)
+{
+	const char *res;
+
+	switch (eventId)
+	{
+		case EVENT_ARCHIVER_MAIN:
+			res = "ArchiverMain";
+			break;
+		case EVENT_AUTOVACUUM_MAIN:
+			res = "AutoVacuumMain";
+			break;
+		case EVENT_BASEBACKUP_THROTTLE:
+			res = "BaseBackupThrottle";
+			break;
+		case EVENT_BGWORKER_STARTUP:
+			res = "BgWorkerStartup";
+			break;
+		case EVENT_BGWORKER_SHUTDOWN:
+			res = "BgWorkerShutdown";
+			break;
+		case EVENT_BGWRITER_MAIN:
+			res = "BgWriterMain";
+			break;
+		case EVENT_BGWRITER_HIBERNATE:
+			res = "BgWriterHibernate";
+			break;
+		case EVENT_CHECKPOINTER_MAIN:
+			res = "CheckpointerMain";
+			break;
+		case EVENT_EXECUTE_GATHER:
+			res = "ExecuteGather";
+			break;
+		case EVENT_EXTENSION:
+			res = "Extension";
+			break;
+		case EVENT_MQ_PUT_MESSAGE:
+			res = "MessageQueuePutMessage";
+			break;
+		case EVENT_MQ_SEND_BYTES:
+			res = "MessageQueueSend";
+			break;
+		case EVENT_MQ_RECEIVE_BYTES:
+			res = "MessageQueueReceive";
+			break;
+		case EVENT_MQ_WAIT_INTERNAL:
+			res = "MessageQueueInternal";
+			break;
+		case EVENT_PARALLEL_WAIT_FINISH:
+			res = "ParallelFinish";
+			break;
+		case EVENT_PG_SLEEP:
+			res = "PgSleep";
+			break;
+		case EVENT_PGSTAT_MAIN:
+			res = "PgStatMain";
+			break;
+		case EVENT_PROC_SLEEP:
+			res = "ProcSleep";
+			break;
+		case EVENT_PROC_SIGNAL:
+			res = "ProcSignal";
+			break;
+		case EVENT_RECOVERY_APPLY_DELAY:
+			res = "RecoveryApplyDelay";
+			break;
+		case EVENT_RECOVERY_WAL_STREAM:
+			res = "RecoveryWalStream";
+			break;
+		case EVENT_RECOVERY_WAL_ALL:
+			res = "RecoveryWalAll";
+			break;
+		case EVENT_SECURE_READ:
+			res = "SecureRead";
+			break;
+		case EVENT_SECURE_WRITE:
+			res = "SecureWrite";
+			break;
+		case EVENT_SSL_OPEN_SERVER:
+			res = "SSLOpenServer";
+			break;
+		case EVENT_SYNC_REP:
+			res = "SyncRep";
+			break;
+		case EVENT_SYSLOGGER_MAIN:
+			res = "SysLoggerMain";
+			break;
+		case EVENT_WALWRITER_MAIN:
+			res = "WalWriterMain";
+			break;
+		case EVENT_WAL_RECEIVER_WAIT_START:
+			res = "WalSenderWaitStart";
+			break;
+		case EVENT_WAL_RECEIVER_MAIN:
+			res = "WalReceiverMain";
+			break;
+		case EVENT_WAL_SENDER_LOOP:
+			res = "WalSenderMain";
+			break;
+		case EVENT_WAL_SENDER_WAIT_WAL:
+			res = "WalSenderWaitForWAL";
+			break;
+		case EVENT_WAL_SENDER_WRITE_DATA:
+			res = "WalSenderWriteData";
+			break;
+		default:
+			res = "???";
+	}
+
+	return res;
+}
+
+
 /*
  * SetLatch uses SIGUSR1 to wake up the process waiting on the latch.
  *
diff --git a/src/backend/storage/ipc/shm_mq.c b/src/backend/storage/ipc/shm_mq.c
index 5b32782..af5344c 100644
--- a/src/backend/storage/ipc/shm_mq.c
+++ b/src/backend/storage/ipc/shm_mq.c
@@ -894,7 +894,7 @@ shm_mq_send_bytes(shm_mq_handle *mqh, Size nbytes, const void *data,
 			 * at top of loop, because setting an already-set latch is much
 			 * cheaper than setting one that has been reset.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_MQ_SEND_BYTES);
 
 			/* Reset the latch so we don't spin. */
 			ResetLatch(MyLatch);
@@ -991,7 +991,7 @@ shm_mq_receive_bytes(shm_mq *mq, Size bytes_needed, bool nowait,
 		 * loop, because setting an already-set latch is much cheaper than
 		 * setting one that has been reset.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_MQ_RECEIVE_BYTES);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
@@ -1090,7 +1090,7 @@ shm_mq_wait_internal(volatile shm_mq *mq, PGPROC *volatile * ptr,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_MQ_WAIT_INTERNAL);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 9a758bd..2ed3f41 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -1216,7 +1216,7 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
 		}
 		else
 		{
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_PROC_SLEEP);
 			ResetLatch(MyLatch);
 			/* check for deadlocks first, as that's probably log-worthy */
 			if (got_deadlock_timeout)
@@ -1728,7 +1728,7 @@ CheckDeadLockAlert(void)
 void
 ProcWaitForSignal(void)
 {
-	WaitLatch(MyLatch, WL_LATCH_SET, 0);
+	WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_PROC_SIGNAL);
 	ResetLatch(MyLatch);
 	CHECK_FOR_INTERRUPTS();
 }
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 5e705e9..ea88c87 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -560,7 +560,7 @@ pg_sleep(PG_FUNCTION_ARGS)
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | WL_TIMEOUT,
-						 delay_ms);
+						 delay_ms, EVENT_PG_SLEEP);
 		ResetLatch(MyLatch);
 	}
 
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index dc3320d..bca16e4 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -721,7 +721,8 @@ typedef enum WaitClass
 	WAIT_LWLOCK_NAMED,
 	WAIT_LWLOCK_TRANCHE,
 	WAIT_LOCK,
-	WAIT_BUFFER_PIN
+	WAIT_BUFFER_PIN,
+	WAIT_EVENT_SET
 }	WaitClass;
 
 
diff --git a/src/include/storage/latch.h b/src/include/storage/latch.h
index 5179ecc..41dc553 100644
--- a/src/include/storage/latch.h
+++ b/src/include/storage/latch.h
@@ -135,6 +135,47 @@ typedef struct WaitEvent
 	void	   *user_data;		/* pointer provided in AddWaitEventToSet */
 } WaitEvent;
 
+/*
+ * List of latch identifiers used when reporting activity to statistics
+ * collector.
+ */
+typedef enum EventIdentifier
+{
+	EVENT_ARCHIVER_MAIN,
+	EVENT_AUTOVACUUM_MAIN,
+	EVENT_BASEBACKUP_THROTTLE,
+	EVENT_BGWORKER_STARTUP,
+	EVENT_BGWORKER_SHUTDOWN,
+	EVENT_BGWRITER_MAIN,
+	EVENT_BGWRITER_HIBERNATE,
+	EVENT_CHECKPOINTER_MAIN,
+	EVENT_EXECUTE_GATHER,
+	EVENT_EXTENSION,
+	EVENT_MQ_PUT_MESSAGE,
+	EVENT_MQ_SEND_BYTES,
+	EVENT_MQ_RECEIVE_BYTES,
+	EVENT_MQ_WAIT_INTERNAL,
+	EVENT_PARALLEL_WAIT_FINISH,
+	EVENT_PGSTAT_MAIN,
+	EVENT_PROC_SLEEP,
+	EVENT_PROC_SIGNAL,
+	EVENT_PG_SLEEP,
+	EVENT_SECURE_READ,
+	EVENT_SECURE_WRITE,
+	EVENT_SSL_OPEN_SERVER,
+	EVENT_SYNC_REP,
+	EVENT_SYSLOGGER_MAIN,
+	EVENT_RECOVERY_APPLY_DELAY,
+	EVENT_RECOVERY_WAL_ALL,
+	EVENT_RECOVERY_WAL_STREAM,
+	EVENT_WAL_RECEIVER_WAIT_START,
+	EVENT_WAL_RECEIVER_MAIN,
+	EVENT_WAL_SENDER_WRITE_DATA,
+	EVENT_WAL_SENDER_LOOP,
+	EVENT_WAL_SENDER_WAIT_WAL,
+	EVENT_WALWRITER_MAIN
+} EventIdentifier;
+
 /* forward declaration to avoid exposing latch.c implementation details */
 typedef struct WaitEventSet WaitEventSet;
 
@@ -155,10 +196,14 @@ extern int AddWaitEventToSet(WaitEventSet *set, uint32 events, pgsocket fd,
 				  Latch *latch, void *user_data);
 extern void ModifyWaitEvent(WaitEventSet *set, int pos, uint32 events, Latch *latch);
 
-extern int	WaitEventSetWait(WaitEventSet *set, long timeout, WaitEvent *occurred_events, int nevents);
-extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout);
+extern int	WaitEventSetWait(WaitEventSet *set, long timeout,
+				  WaitEvent *occurred_events, int nevents,
+				  EventIdentifier eventId);
+extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+				  EventIdentifier eventId);
 extern int WaitLatchOrSocket(volatile Latch *latch, int wakeEvents,
-				  pgsocket sock, long timeout);
+				  pgsocket sock, long timeout, EventIdentifier eventId);
+extern const char *GetEventIdentifier(uint16 eventId);
 
 /*
  * Unix implementation uses SIGUSR1 for inter-process signaling.
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 143df4e..d32e42e 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -279,7 +279,7 @@ wait_for_workers_to_become_ready(worker_state *wstate,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_EXTENSION);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/test/modules/test_shm_mq/test.c b/src/test/modules/test_shm_mq/test.c
index dd34bc7..caddf83 100644
--- a/src/test/modules/test_shm_mq/test.c
+++ b/src/test/modules/test_shm_mq/test.c
@@ -230,7 +230,7 @@ test_shm_mq_pipelined(PG_FUNCTION_ARGS)
 			 * have read or written data and therefore there may now be work
 			 * for us to do.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_EXTENSION);
 			ResetLatch(MyLatch);
 			CHECK_FOR_INTERRUPTS();
 		}
diff --git a/src/test/modules/worker_spi/worker_spi.c b/src/test/modules/worker_spi/worker_spi.c
index 314e371..bb0d7ff 100644
--- a/src/test/modules/worker_spi/worker_spi.c
+++ b/src/test/modules/worker_spi/worker_spi.c
@@ -227,7 +227,8 @@ worker_spi_main(Datum main_arg)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   worker_spi_naptime * 1000L);
+					   worker_spi_naptime * 1000L,
+					   EVENT_EXTENSION);
 		ResetLatch(MyLatch);
 
 		/* emergency bailout if postmaster has died */

diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 8ca1c1c..954a166 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -496,7 +496,7 @@ pgfdw_get_result(PGconn *conn, const char *query)
 			wc = WaitLatchOrSocket(MyLatch,
 								   WL_LATCH_SET | WL_SOCKET_READABLE,
 								   PQsocket(conn),
-								   -1L);
+								   -1L, EVENT_EXTENSION);
 			ResetLatch(MyLatch);
 
 			CHECK_FOR_INTERRUPTS();
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 0776428..a14abe4 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -679,6 +679,16 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
           buffer in question.
          </para>
         </listitem>
+        <listitem>
+         <para>
+          <literal>EventSet</>: The server process is waiting on a socket
+          or a timer. This wait happens in a latch, an inter-process facility
+          using boolean variables letting a process sleep until it is set.
+          Latches support several type of operations, like postmaster death
+          handling, timeout and socket activity lookup, and are a useful
+          replacement for <function>sleep</> where signal handling matters.
+         </para>
+        </listitem>
        </itemizedlist>
       </entry>
      </row>
@@ -1085,6 +1095,139 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
          <entry><literal>BufferPin</></entry>
          <entry>Waiting to acquire a pin on a buffer.</entry>
         </row>
+        <row>
+         <entry morerows="32"><literal>EventSet</></entry>
+         <entry><literal>ArchiverMain</></entry>
+         <entry>Waiting in main loop of the archiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>AutoVacuumMain</></entry>
+         <entry>Waiting in main loop of autovacuum launcher process.</entry>
+        </row>
+        <row>
+         <entry><literal>BaseBackupThrottle</></entry>
+         <entry>Waiting during base backup when throttling activity.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWorkerStartup</></entry>
+         <entry>Waiting for background worker to start up.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWorkerShutdown</></entry>
+         <entry>Waiting for background worker to shut down.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterMain</></entry>
+         <entry>Waiting in main loop of background writer process background worker.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterHibernate</></entry>
+         <entry>Waiting in background writer process, hibernating.</entry>
+        </row>
+        <row>
+         <entry><literal>CheckpointerMain</></entry>
+         <entry>Waiting in main loop of checkpointer process.</entry>
+        </row>
+        <row>
+         <entry><literal>ExecuteGather</></entry>
+         <entry>Waiting for activity from child process when executing <literal>Gather</> node.</entry>
+        </row>
+        <row>
+         <entry><literal>Extension</></entry>
+         <entry>Waiting in the code path of an extension, should be used by custom plugins and modules</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueuePutMessage</></entry>
+         <entry>Waiting to put new message in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueSend</></entry>
+         <entry>Waiting to send bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueReceive</></entry>
+         <entry>Waiting to receive bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueInternal</></entry>
+         <entry>Waiting for other process to be attached in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>ParallelFinish</></entry>
+         <entry>Waiting for parallel workers to finish computing.</entry>
+        </row>
+        <row>
+         <entry><literal>PgSleep</></entry>
+         <entry>Waiting in process that called <function>pg_sleep</>.</entry>
+        </row>
+        <row>
+         <entry><literal>PgStatMain</></entry>
+         <entry>Waiting in main loop of the statistics collector process.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSleep</></entry>
+         <entry>Waiting for a specific lock.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSignal</></entry>
+         <entry>Waiting for signal from another backend.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryApplyDelay</></entry>
+         <entry>Waiting to apply WAL at recovery because it is delayed.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalStream</></entry>
+         <entry>Waiting for WAL from a stream at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalAll</></entry>
+         <entry>Waiting for WAL from any kind of source (local, archive or stream) at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>SecureRead</></entry>
+         <entry>Waiting to read data from a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SecureWrite</></entry>
+         <entry>Waiting to write data to a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SSLOpenServer</></entry>
+         <entry>Waiting for SSL while attempting connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SyncRep</></entry>
+         <entry>Waiting for WAL commit during synchronous replication.</entry>
+        </row>
+        <row>
+         <entry><literal>SysLoggerMain</></entry>
+         <entry>Waiting in main loop of syslogger process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalWriterMain</></entry>
+         <entry>Waiting in main loop of WAL writer process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverWaitStart</></entry>
+         <entry>Waiting for startup process to send initial data for streaming replication.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverMain</></entry>
+         <entry>Waiting in main loop of WAL receiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderMain</></entry>
+         <entry>Waiting in main loop of WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWaitForWAL</></entry>
+         <entry>Waiting for WAL to be flushed in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWriteData</></entry>
+         <entry>Waiting for any activity when processing replies from WAL receiver in WAL sender process.</entry>
+        </row>
       </tbody>
      </tgroup>
     </table>
diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c
index a47eba6..2495e61 100644
--- a/src/backend/access/transam/parallel.c
+++ b/src/backend/access/transam/parallel.c
@@ -541,7 +541,8 @@ WaitForParallelWorkersToFinish(ParallelContext *pcxt)
 		if (!anyone_alive)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1,
+				  EVENT_PARALLEL_WAIT_FINISH);
 		ResetLatch(&MyProc->procLatch);
 	}
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index f13f9c1..19d9977 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5756,7 +5756,8 @@ recoveryApplyDelay(XLogReaderState *record)
 
 		WaitLatch(&XLogCtl->recoveryWakeupLatch,
 				  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-				  secs * 1000L + microsecs / 1000);
+				  secs * 1000L + microsecs / 1000,
+				  EVENT_RECOVERY_APPLY_DELAY);
 	}
 	return true;
 }
@@ -11294,7 +11295,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 
 						WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								  wait_time);
+							 wait_time, EVENT_RECOVERY_WAL_STREAM);
 						ResetLatch(&XLogCtl->recoveryWakeupLatch);
 						now = GetCurrentTimestamp();
 					}
@@ -11457,7 +11458,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					 */
 					WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							  5000L);
+							  5000L, EVENT_RECOVERY_WAL_ALL);
 					ResetLatch(&XLogCtl->recoveryWakeupLatch);
 					break;
 				}
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 438d1b2..d8fe2a5 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -387,7 +387,7 @@ gather_readnext(GatherState *gatherstate)
 				return NULL;
 
 			/* Nothing to do except wait for developments. */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_EXECUTE_GATHER);
 			ResetLatch(MyLatch);
 			nvisited = 0;
 		}
diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
index f6adb15..759b337 100644
--- a/src/backend/libpq/be-secure-openssl.c
+++ b/src/backend/libpq/be-secure-openssl.c
@@ -418,7 +418,8 @@ aloop:
 				else
 					waitfor = WL_SOCKET_WRITEABLE;
 
-				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0);
+				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0,
+								  EVENT_SSL_OPEN_SERVER);
 				goto aloop;
 			case SSL_ERROR_SYSCALL:
 				if (r < 0)
diff --git a/src/backend/libpq/be-secure.c b/src/backend/libpq/be-secure.c
index cdd07d5..5880818 100644
--- a/src/backend/libpq/be-secure.c
+++ b/src/backend/libpq/be-secure.c
@@ -146,7 +146,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 EVENT_SECURE_READ);
 
 		/*
 		 * If the postmaster has died, it's not safe to continue running,
@@ -247,7 +248,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 EVENT_SECURE_WRITE);
 
 		/* See comments in secure_read. */
 		if (event.events & WL_POSTMASTER_DEATH)
diff --git a/src/backend/libpq/pqmq.c b/src/backend/libpq/pqmq.c
index 921242f..6c39e51 100644
--- a/src/backend/libpq/pqmq.c
+++ b/src/backend/libpq/pqmq.c
@@ -171,7 +171,7 @@ mq_putmessage(char msgtype, const char *s, size_t len)
 		if (result != SHM_MQ_WOULD_BLOCK)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0, EVENT_MQ_PUT_MESSAGE);
 		ResetLatch(&MyProc->procLatch);
 		CHECK_FOR_INTERRUPTS();
 	}
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 3768f50..bb80c11 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -600,7 +600,8 @@ AutoVacLauncherMain(int argc, char *argv[])
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L));
+					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L),
+					   EVENT_AUTOVACUUM_MAIN);
 
 		ResetLatch(MyLatch);
 
diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c
index 699c934..ee4ed7e 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -969,7 +969,8 @@ WaitForBackgroundWorkerStartup(BackgroundWorkerHandle *handle, pid_t *pidp)
 			break;
 
 		rc = WaitLatch(MyLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   EVENT_BGWORKER_STARTUP);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
@@ -1008,7 +1009,8 @@ WaitForBackgroundWorkerShutdown(BackgroundWorkerHandle *handle)
 			break;
 
 		rc = WaitLatch(&MyProc->procLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   EVENT_BGWORKER_SHUTDOWN);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index 00f03d8..1c135de 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -347,7 +347,8 @@ BackgroundWriterMain(void)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   BgWriterDelay /* ms */ );
+					   BgWriterDelay /* ms */,
+					   EVENT_BGWRITER_MAIN);
 
 		/*
 		 * If no latch event and BgBufferSync says nothing's happening, extend
@@ -374,7 +375,8 @@ BackgroundWriterMain(void)
 			/* Sleep ... */
 			rc = WaitLatch(MyLatch,
 						   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-						   BgWriterDelay * HIBERNATE_FACTOR);
+						   BgWriterDelay * HIBERNATE_FACTOR,
+						   EVENT_BGWRITER_HIBERNATE);
 			/* Reset the notification request in case we timed out */
 			StrategyNotifyBgWriter(-1);
 		}
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index 8d4b353..60bab87 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -558,7 +558,8 @@ CheckpointerMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout * 1000L /* convert to ms */ );
+					   cur_timeout * 1000L /* convert to ms */,
+					   EVENT_CHECKPOINTER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 1aa6466..156fff7 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -390,7 +390,7 @@ pgarch_MainLoop(void)
 
 				rc = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							   timeout * 1000L);
+							 timeout * 1000L, EVENT_ARCHIVER_MAIN);
 				if (rc & WL_TIMEOUT)
 					wakened = true;
 			}
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 8fa9edb..08384dc 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -3152,6 +3152,9 @@ pgstat_get_wait_event_type(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_type = "BufferPin";
 			break;
+		case WAIT_EVENT_SET:
+			event_type = "EventSet";
+			break;
 		default:
 			event_type = "???";
 			break;
@@ -3193,6 +3196,9 @@ pgstat_get_wait_event(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_name = "BufferPin";
 			break;
+		case WAIT_EVENT_SET:
+			event_name = GetWaitEventIdentifier(eventId);
+			break;
 		default:
 			event_name = "unknown wait event";
 			break;
@@ -3682,7 +3688,7 @@ PgstatCollectorMain(int argc, char *argv[])
 		wr = WaitLatchOrSocket(MyLatch,
 					 WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE,
 							   pgStatSock,
-							   -1L);
+							   -1L, EVENT_PGSTAT_MAIN);
 #else
 
 		/*
@@ -3698,7 +3704,8 @@ PgstatCollectorMain(int argc, char *argv[])
 		wr = WaitLatchOrSocket(MyLatch,
 		WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE | WL_TIMEOUT,
 							   pgStatSock,
-							   2 * 1000L /* msec */ );
+							   2 * 1000L /* msec */,
+							   EVENT_PGSTAT_MAIN);
 #endif
 
 		/*
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index e7e488a..c147fd1 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -424,7 +424,8 @@ SysLoggerMain(int argc, char *argv[])
 		rc = WaitLatchOrSocket(MyLatch,
 							   WL_LATCH_SET | WL_SOCKET_READABLE | cur_flags,
 							   syslogPipe[0],
-							   cur_timeout);
+							   cur_timeout,
+							   EVENT_SYSLOGGER_MAIN);
 
 		if (rc & WL_SOCKET_READABLE)
 		{
@@ -475,7 +476,8 @@ SysLoggerMain(int argc, char *argv[])
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | cur_flags,
-						 cur_timeout);
+						 cur_timeout,
+						 EVENT_SYSLOGGER_MAIN);
 
 		EnterCriticalSection(&sysloggerSection);
 #endif   /* WIN32 */
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index 228190a..781e7b0 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -292,7 +292,8 @@ WalWriterMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout);
+					   cur_timeout,
+					   EVENT_WALWRITER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index da9b7a6..308220f 100644
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -1286,7 +1286,8 @@ throttle(size_t increment)
 		 */
 		wait_result = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								(long) (sleep / 1000));
+								(long) (sleep / 1000),
+								EVENT_BASEBACKUP_THROTTLE);
 
 		if (wait_result & WL_LATCH_SET)
 			CHECK_FOR_INTERRUPTS();
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index b442d06..2884944 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -258,7 +258,8 @@ SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
 		 * Wait on latch.  Any condition that should wake us up will set the
 		 * latch, so no need for timeout.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1);
+		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1,
+				  EVENT_SYNC_REP);
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 413ee3a..dfd7d37 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -486,7 +486,8 @@ WalReceiverMain(void)
 								   WL_POSTMASTER_DEATH | WL_SOCKET_READABLE |
 									   WL_TIMEOUT | WL_LATCH_SET,
 									   wait_fd,
-									   NAPTIME_PER_CYCLE);
+									   NAPTIME_PER_CYCLE,
+									   EVENT_WAL_RECEIVER_MAIN);
 				if (rc & WL_LATCH_SET)
 				{
 					ResetLatch(&walrcv->latch);
@@ -685,7 +686,8 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 		}
 		SpinLockRelease(&walrcv->mutex);
 
-		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+				  EVENT_WAL_RECEIVER_WAIT_START);
 	}
 
 	if (update_process_title)
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index a0dba19..45d9471 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -1146,7 +1146,8 @@ WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid,
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  EVENT_WAL_SENDER_WRITE_DATA);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1272,7 +1273,8 @@ WalSndWaitForWal(XLogRecPtr loc)
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  EVENT_WAL_SENDER_WAIT_WAL);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1923,7 +1925,8 @@ WalSndLoop(WalSndSendDataCallback send_data)
 
 			/* Sleep until something happens or we time out */
 			WaitLatchOrSocket(MyLatch, wakeEvents,
-							  MyProcPort->sock, sleeptime);
+							  MyProcPort->sock, sleeptime,
+							  EVENT_WAL_SENDER_MAIN);
 		}
 	}
 	return;
diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c
index 9def8a1..e6cc6d0 100644
--- a/src/backend/storage/ipc/latch.c
+++ b/src/backend/storage/ipc/latch.c
@@ -55,6 +55,7 @@
 #endif
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "portability/instr_time.h"
 #include "postmaster/postmaster.h"
 #include "storage/barrier.h"
@@ -122,6 +123,43 @@ struct WaitEventSet
 #endif
 };
 
+/* This must match enum WaitEventIdentifier! */
+const char *const WaitEventNames[] = {
+	"ArchiverMain",
+	"AutoVacuumMain",
+	"BaseBackupThrottle",
+	"BgWorkerStartup",
+	"BgWorkerShutdown",
+	"BgWriterMain",
+	"BgWriterHibernate",
+	"CheckpointerMain",
+	"ExecuteGather",
+	"Extension",
+	"MessageQueuePutMessage",
+	"MessageQueueSend",
+	"MessageQueueReceive",
+	"MessageQueueInternal",
+	"ParallelFinish",
+	"PgStatMain",
+	"ProcSleep",
+	"ProcSignal",
+	"PgSleep",
+	"SecureRead",
+	"SecureWrite",
+	"SSLOpenServer",
+	"SyncRep",
+	"SysLoggerMain",
+	"RecoveryApplyDelay",
+	"RecoveryWalAll",
+	"RecoveryWalStream",
+	"WalReceiverWaitStart",
+	"WalReceiverMain",
+	"WalSenderMain",
+	"WalSenderWaitForWAL",
+	"WalSenderWriteData"
+	"WalWriterMain",
+};
+
 #ifndef WIN32
 /* Are we currently in WaitLatch? The signal handler would like to know. */
 static volatile sig_atomic_t waiting = false;
@@ -297,9 +335,11 @@ DisownLatch(volatile Latch *latch)
  * we return all of them in one call, but we will return at least one.
  */
 int
-WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
+WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+		  WaitEventIdentifier eventId)
 {
-	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout);
+	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout,
+							 eventId);
 }
 
 /*
@@ -316,7 +356,7 @@ WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
  */
 int
 WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
-				  long timeout)
+				  long timeout, WaitEventIdentifier eventId)
 {
 	int			ret = 0;
 	int			rc;
@@ -344,7 +384,7 @@ WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
 		AddWaitEventToSet(set, ev, sock, NULL, NULL);
 	}
 
-	rc = WaitEventSetWait(set, timeout, &event, 1);
+	rc = WaitEventSetWait(set, timeout, &event, 1, eventId);
 
 	if (rc == 0)
 		ret |= WL_TIMEOUT;
@@ -863,7 +903,8 @@ WaitEventAdjustWin32(WaitEventSet *set, WaitEvent *event)
  */
 int
 WaitEventSetWait(WaitEventSet *set, long timeout,
-				 WaitEvent *occurred_events, int nevents)
+				 WaitEvent *occurred_events, int nevents,
+				 WaitEventIdentifier eventId)
 {
 	int			returned_events = 0;
 	instr_time	start_time;
@@ -872,6 +913,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 
 	Assert(nevents > 0);
 
+	pgstat_report_wait_start(WAIT_EVENT_SET, (uint16) eventId);
+
 	/*
 	 * Initialize timeout if requested.  We must record the current time so
 	 * that we can determine the remaining timeout if interrupted.
@@ -960,6 +1003,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 	waiting = false;
 #endif
 
+	pgstat_report_wait_end();
+
 	return returned_events;
 }
 
@@ -1491,6 +1536,20 @@ WaitEventSetWaitBlock(WaitEventSet *set, int cur_timeout,
 }
 #endif
 
+
+/*
+ * Return an identifier for a Latch depending on an event for statistics
+ * collector.
+ */
+const char *
+GetWaitEventIdentifier(uint16 eventId)
+{
+	if (eventId > EVENT_LAST_TYPE)
+		return "???";
+	return WaitEventNames[eventId];
+}
+
+
 /*
  * SetLatch uses SIGUSR1 to wake up the process waiting on the latch.
  *
diff --git a/src/backend/storage/ipc/shm_mq.c b/src/backend/storage/ipc/shm_mq.c
index 5b32782..af5344c 100644
--- a/src/backend/storage/ipc/shm_mq.c
+++ b/src/backend/storage/ipc/shm_mq.c
@@ -894,7 +894,7 @@ shm_mq_send_bytes(shm_mq_handle *mqh, Size nbytes, const void *data,
 			 * at top of loop, because setting an already-set latch is much
 			 * cheaper than setting one that has been reset.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_MQ_SEND_BYTES);
 
 			/* Reset the latch so we don't spin. */
 			ResetLatch(MyLatch);
@@ -991,7 +991,7 @@ shm_mq_receive_bytes(shm_mq *mq, Size bytes_needed, bool nowait,
 		 * loop, because setting an already-set latch is much cheaper than
 		 * setting one that has been reset.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_MQ_RECEIVE_BYTES);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
@@ -1090,7 +1090,7 @@ shm_mq_wait_internal(volatile shm_mq *mq, PGPROC *volatile * ptr,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_MQ_WAIT_INTERNAL);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 9a758bd..2ed3f41 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -1216,7 +1216,7 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
 		}
 		else
 		{
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_PROC_SLEEP);
 			ResetLatch(MyLatch);
 			/* check for deadlocks first, as that's probably log-worthy */
 			if (got_deadlock_timeout)
@@ -1728,7 +1728,7 @@ CheckDeadLockAlert(void)
 void
 ProcWaitForSignal(void)
 {
-	WaitLatch(MyLatch, WL_LATCH_SET, 0);
+	WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_PROC_SIGNAL);
 	ResetLatch(MyLatch);
 	CHECK_FOR_INTERRUPTS();
 }
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 5e705e9..ea88c87 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -560,7 +560,7 @@ pg_sleep(PG_FUNCTION_ARGS)
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | WL_TIMEOUT,
-						 delay_ms);
+						 delay_ms, EVENT_PG_SLEEP);
 		ResetLatch(MyLatch);
 	}
 
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index dc3320d..bca16e4 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -721,7 +721,8 @@ typedef enum WaitClass
 	WAIT_LWLOCK_NAMED,
 	WAIT_LWLOCK_TRANCHE,
 	WAIT_LOCK,
-	WAIT_BUFFER_PIN
+	WAIT_BUFFER_PIN,
+	WAIT_EVENT_SET
 }	WaitClass;
 
 
diff --git a/src/include/storage/latch.h b/src/include/storage/latch.h
index 5179ecc..18c78de 100644
--- a/src/include/storage/latch.h
+++ b/src/include/storage/latch.h
@@ -135,6 +135,51 @@ typedef struct WaitEvent
 	void	   *user_data;		/* pointer provided in AddWaitEventToSet */
 } WaitEvent;
 
+/*
+ * List of latch identifiers used when reporting activity to statistics
+ * collector. Up to 256 different WaitEventIdentifier can be handled.
+ */
+typedef enum WaitEventIdentifier
+{
+	EVENT_ARCHIVER_MAIN,
+	EVENT_AUTOVACUUM_MAIN,
+	EVENT_BASEBACKUP_THROTTLE,
+	EVENT_BGWORKER_STARTUP,
+	EVENT_BGWORKER_SHUTDOWN,
+	EVENT_BGWRITER_MAIN,
+	EVENT_BGWRITER_HIBERNATE,
+	EVENT_CHECKPOINTER_MAIN,
+	EVENT_EXECUTE_GATHER,
+	EVENT_EXTENSION,
+	EVENT_MQ_PUT_MESSAGE,
+	EVENT_MQ_SEND_BYTES,
+	EVENT_MQ_RECEIVE_BYTES,
+	EVENT_MQ_WAIT_INTERNAL,
+	EVENT_PARALLEL_WAIT_FINISH,
+	EVENT_PGSTAT_MAIN,
+	EVENT_PROC_SLEEP,
+	EVENT_PROC_SIGNAL,
+	EVENT_PG_SLEEP,
+	EVENT_SECURE_READ,
+	EVENT_SECURE_WRITE,
+	EVENT_SSL_OPEN_SERVER,
+	EVENT_SYNC_REP,
+	EVENT_SYSLOGGER_MAIN,
+	EVENT_RECOVERY_APPLY_DELAY,
+	EVENT_RECOVERY_WAL_ALL,
+	EVENT_RECOVERY_WAL_STREAM,
+	EVENT_WAL_RECEIVER_WAIT_START,
+	EVENT_WAL_RECEIVER_MAIN,
+	EVENT_WAL_SENDER_WRITE_DATA,
+	EVENT_WAL_SENDER_MAIN,
+	EVENT_WAL_SENDER_WAIT_WAL,
+	EVENT_WALWRITER_MAIN
+} WaitEventIdentifier;
+
+#define EVENT_LAST_TYPE EVENT_WALWRITER_MAIN
+
+extern const char *const WaitEventName[];
+
 /* forward declaration to avoid exposing latch.c implementation details */
 typedef struct WaitEventSet WaitEventSet;
 
@@ -155,10 +200,14 @@ extern int AddWaitEventToSet(WaitEventSet *set, uint32 events, pgsocket fd,
 				  Latch *latch, void *user_data);
 extern void ModifyWaitEvent(WaitEventSet *set, int pos, uint32 events, Latch *latch);
 
-extern int	WaitEventSetWait(WaitEventSet *set, long timeout, WaitEvent *occurred_events, int nevents);
-extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout);
+extern int	WaitEventSetWait(WaitEventSet *set, long timeout,
+				  WaitEvent *occurred_events, int nevents,
+				  WaitEventIdentifier eventId);
+extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+				  WaitEventIdentifier eventId);
 extern int WaitLatchOrSocket(volatile Latch *latch, int wakeEvents,
-				  pgsocket sock, long timeout);
+				  pgsocket sock, long timeout, WaitEventIdentifier eventId);
+extern const char *GetWaitEventIdentifier(uint16 eventId);
 
 /*
  * Unix implementation uses SIGUSR1 for inter-process signaling.
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 143df4e..d32e42e 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -279,7 +279,7 @@ wait_for_workers_to_become_ready(worker_state *wstate,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_EXTENSION);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/test/modules/test_shm_mq/test.c b/src/test/modules/test_shm_mq/test.c
index dd34bc7..caddf83 100644
--- a/src/test/modules/test_shm_mq/test.c
+++ b/src/test/modules/test_shm_mq/test.c
@@ -230,7 +230,7 @@ test_shm_mq_pipelined(PG_FUNCTION_ARGS)
 			 * have read or written data and therefore there may now be work
 			 * for us to do.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, EVENT_EXTENSION);
 			ResetLatch(MyLatch);
 			CHECK_FOR_INTERRUPTS();
 		}
diff --git a/src/test/modules/worker_spi/worker_spi.c b/src/test/modules/worker_spi/worker_spi.c
index 314e371..bb0d7ff 100644
--- a/src/test/modules/worker_spi/worker_spi.c
+++ b/src/test/modules/worker_spi/worker_spi.c
@@ -227,7 +227,8 @@ worker_spi_main(Datum main_arg)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   worker_spi_naptime * 1000L);
+					   worker_spi_naptime * 1000L,
+					   EVENT_EXTENSION);
 		ResetLatch(MyLatch);
 
 		/* emergency bailout if postmaster has died */

diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 8ca1c1c..7cecef8 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -496,7 +496,7 @@ pgfdw_get_result(PGconn *conn, const char *query)
 			wc = WaitLatchOrSocket(MyLatch,
 								   WL_LATCH_SET | WL_SOCKET_READABLE,
 								   PQsocket(conn),
-								   -1L);
+								   -1L, WE_EXTENSION);
 			ResetLatch(MyLatch);
 
 			CHECK_FOR_INTERRUPTS();
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 0776428..5185d65 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -679,6 +679,18 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
           buffer in question.
          </para>
         </listitem>
+        <listitem>
+         <para>
+          <literal>EventSet</>: The server process is waiting on one or more
+          sockets, a time or an inter-process latch.  The wait happens in a
+          <function>WaitEventSet</>, <productname>PostgreSQL</>'s portable
+          I/O multiplexing abstraction using boolean variables letting a
+          process sleep until it is set.  It supports several type of
+          operations, like postmaster death handling, timeout and socket
+          activity lookup, and are a useful replacement for <function>sleep</>
+          where signal handling matters.
+         </para>
+        </listitem>
        </itemizedlist>
       </entry>
      </row>
@@ -1085,6 +1097,139 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
          <entry><literal>BufferPin</></entry>
          <entry>Waiting to acquire a pin on a buffer.</entry>
         </row>
+        <row>
+         <entry morerows="32"><literal>EventSet</></entry>
+         <entry><literal>ArchiverMain</></entry>
+         <entry>Waiting in main loop of the archiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>AutoVacuumMain</></entry>
+         <entry>Waiting in main loop of autovacuum launcher process.</entry>
+        </row>
+        <row>
+         <entry><literal>BaseBackupThrottle</></entry>
+         <entry>Waiting during base backup when throttling activity.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWorkerShutdown</></entry>
+         <entry>Waiting for background worker to shut down.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWorkerStartup</></entry>
+         <entry>Waiting for background worker to start up.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterHibernate</></entry>
+         <entry>Waiting in background writer process, hibernating.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterMain</></entry>
+         <entry>Waiting in main loop of background writer process background worker.</entry>
+        </row>
+        <row>
+         <entry><literal>CheckpointerMain</></entry>
+         <entry>Waiting in main loop of checkpointer process.</entry>
+        </row>
+        <row>
+         <entry><literal>ExecuteGather</></entry>
+         <entry>Waiting for activity from child process when executing <literal>Gather</> node.</entry>
+        </row>
+        <row>
+         <entry><literal>Extension</></entry>
+         <entry>Waiting in the code path of an extension, should be used by custom plugins and modules</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueInternal</></entry>
+         <entry>Waiting for other process to be attached in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueuePutMessage</></entry>
+         <entry>Waiting to put new message in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueReceive</></entry>
+         <entry>Waiting to receive bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueSend</></entry>
+         <entry>Waiting to send bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>ParallelFinish</></entry>
+         <entry>Waiting for parallel workers to finish computing.</entry>
+        </row>
+        <row>
+         <entry><literal>PgSleep</></entry>
+         <entry>Waiting in process that called <function>pg_sleep</>.</entry>
+        </row>
+        <row>
+         <entry><literal>PgStatMain</></entry>
+         <entry>Waiting in main loop of the statistics collector process.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSignal</></entry>
+         <entry>Waiting for signal from another backend.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSleep</></entry>
+         <entry>Waiting for a specific lock.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryApplyDelay</></entry>
+         <entry>Waiting to apply WAL at recovery because it is delayed.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalAll</></entry>
+         <entry>Waiting for WAL from any kind of source (local, archive or stream) at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalStream</></entry>
+         <entry>Waiting for WAL from a stream at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>SecureRead</></entry>
+         <entry>Waiting to read data from a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SecureWrite</></entry>
+         <entry>Waiting to write data to a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SSLOpenServer</></entry>
+         <entry>Waiting for SSL while attempting connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SyncRep</></entry>
+         <entry>Waiting for WAL commit during synchronous replication.</entry>
+        </row>
+        <row>
+         <entry><literal>SysLoggerMain</></entry>
+         <entry>Waiting in main loop of syslogger process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverMain</></entry>
+         <entry>Waiting in main loop of WAL receiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverWaitStart</></entry>
+         <entry>Waiting for startup process to send initial data for streaming replication.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderMain</></entry>
+         <entry>Waiting in main loop of WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWaitForWAL</></entry>
+         <entry>Waiting for WAL to be flushed in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWriteData</></entry>
+         <entry>Waiting for any activity when processing replies from WAL receiver in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalWriterMain</></entry>
+         <entry>Waiting in main loop of WAL writer process.</entry>
+        </row>
       </tbody>
      </tgroup>
     </table>
diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c
index cde0ed3..60d5c9c 100644
--- a/src/backend/access/transam/parallel.c
+++ b/src/backend/access/transam/parallel.c
@@ -540,7 +540,8 @@ WaitForParallelWorkersToFinish(ParallelContext *pcxt)
 		if (!anyone_alive)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1,
+				  WE_PARALLEL_FINISH);
 		ResetLatch(&MyProc->procLatch);
 	}
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 2189c22..678b6de 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5827,7 +5827,8 @@ recoveryApplyDelay(XLogReaderState *record)
 
 		WaitLatch(&XLogCtl->recoveryWakeupLatch,
 				  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-				  secs * 1000L + microsecs / 1000);
+				  secs * 1000L + microsecs / 1000,
+				  WE_RECOVERY_APPLY_DELAY);
 	}
 	return true;
 }
@@ -11376,7 +11377,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 
 						WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								  wait_time);
+							 wait_time, WE_RECOVERY_WAL_STREAM);
 						ResetLatch(&XLogCtl->recoveryWakeupLatch);
 						now = GetCurrentTimestamp();
 					}
@@ -11539,7 +11540,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					 */
 					WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							  5000L);
+							  5000L, WE_RECOVERY_WAL_ALL);
 					ResetLatch(&XLogCtl->recoveryWakeupLatch);
 					break;
 				}
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 438d1b2..b832d91 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -387,7 +387,7 @@ gather_readnext(GatherState *gatherstate)
 				return NULL;
 
 			/* Nothing to do except wait for developments. */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_EXECUTE_GATHER);
 			ResetLatch(MyLatch);
 			nvisited = 0;
 		}
diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
index fedb02c..571d4d6 100644
--- a/src/backend/libpq/be-secure-openssl.c
+++ b/src/backend/libpq/be-secure-openssl.c
@@ -419,7 +419,8 @@ aloop:
 				else
 					waitfor = WL_SOCKET_WRITEABLE;
 
-				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0);
+				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0,
+								  WE_SSL_OPEN_SERVER);
 				goto aloop;
 			case SSL_ERROR_SYSCALL:
 				if (r < 0)
diff --git a/src/backend/libpq/be-secure.c b/src/backend/libpq/be-secure.c
index cdd07d5..4e16073 100644
--- a/src/backend/libpq/be-secure.c
+++ b/src/backend/libpq/be-secure.c
@@ -146,7 +146,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 WE_SECURE_READ);
 
 		/*
 		 * If the postmaster has died, it's not safe to continue running,
@@ -247,7 +248,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 WE_SECURE_WRITE);
 
 		/* See comments in secure_read. */
 		if (event.events & WL_POSTMASTER_DEATH)
diff --git a/src/backend/libpq/pqmq.c b/src/backend/libpq/pqmq.c
index bfe66c6..625b987 100644
--- a/src/backend/libpq/pqmq.c
+++ b/src/backend/libpq/pqmq.c
@@ -171,7 +171,7 @@ mq_putmessage(char msgtype, const char *s, size_t len)
 		if (result != SHM_MQ_WOULD_BLOCK)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0, WE_MQ_PUT_MESSAGE);
 		ResetLatch(&MyProc->procLatch);
 		CHECK_FOR_INTERRUPTS();
 	}
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 1a92ca1..019075e 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -598,7 +598,8 @@ AutoVacLauncherMain(int argc, char *argv[])
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L));
+					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L),
+					   WE_AUTOVACUUM_MAIN);
 
 		ResetLatch(MyLatch);
 
diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c
index 699c934..7da01df 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -969,7 +969,8 @@ WaitForBackgroundWorkerStartup(BackgroundWorkerHandle *handle, pid_t *pidp)
 			break;
 
 		rc = WaitLatch(MyLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   WE_BGWORKER_STARTUP);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
@@ -1008,7 +1009,8 @@ WaitForBackgroundWorkerShutdown(BackgroundWorkerHandle *handle)
 			break;
 
 		rc = WaitLatch(&MyProc->procLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   WE_BGWORKER_SHUTDOWN);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index 1002034..a89d39d 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -345,7 +345,8 @@ BackgroundWriterMain(void)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   BgWriterDelay /* ms */ );
+					   BgWriterDelay /* ms */,
+					   WE_BGWRITER_MAIN);
 
 		/*
 		 * If no latch event and BgBufferSync says nothing's happening, extend
@@ -372,7 +373,8 @@ BackgroundWriterMain(void)
 			/* Sleep ... */
 			rc = WaitLatch(MyLatch,
 						   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-						   BgWriterDelay * HIBERNATE_FACTOR);
+						   BgWriterDelay * HIBERNATE_FACTOR,
+						   WE_BGWRITER_HIBERNATE);
 			/* Reset the notification request in case we timed out */
 			StrategyNotifyBgWriter(-1);
 		}
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index d702a48..e18ef9f 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -556,7 +556,8 @@ CheckpointerMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout * 1000L /* convert to ms */ );
+					   cur_timeout * 1000L /* convert to ms */,
+					   WE_CHECKPOINTER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 1aa6466..018878c 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -390,7 +390,7 @@ pgarch_MainLoop(void)
 
 				rc = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							   timeout * 1000L);
+							 timeout * 1000L, WE_ARCHIVER_MAIN);
 				if (rc & WL_TIMEOUT)
 					wakened = true;
 			}
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 8a2ce91..110eb50 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -3152,6 +3152,9 @@ pgstat_get_wait_event_type(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_type = "BufferPin";
 			break;
+		case WAIT_EVENT_SET:
+			event_type = "EventSet";
+			break;
 		default:
 			event_type = "???";
 			break;
@@ -3193,6 +3196,9 @@ pgstat_get_wait_event(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_name = "BufferPin";
 			break;
+		case WAIT_EVENT_SET:
+			event_name = GetWaitEventIdentifier(eventId);
+			break;
 		default:
 			event_name = "unknown wait event";
 			break;
@@ -3682,7 +3688,7 @@ PgstatCollectorMain(int argc, char *argv[])
 		wr = WaitLatchOrSocket(MyLatch,
 					 WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE,
 							   pgStatSock,
-							   -1L);
+							   -1L, WE_PGSTAT_MAIN);
 #else
 
 		/*
@@ -3698,7 +3704,8 @@ PgstatCollectorMain(int argc, char *argv[])
 		wr = WaitLatchOrSocket(MyLatch,
 		WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE | WL_TIMEOUT,
 							   pgStatSock,
-							   2 * 1000L /* msec */ );
+							   2 * 1000L /* msec */,
+							   EVENT_PGSTAT_MAIN);
 #endif
 
 		/*
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index e7e488a..5bdfa479 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -424,7 +424,8 @@ SysLoggerMain(int argc, char *argv[])
 		rc = WaitLatchOrSocket(MyLatch,
 							   WL_LATCH_SET | WL_SOCKET_READABLE | cur_flags,
 							   syslogPipe[0],
-							   cur_timeout);
+							   cur_timeout,
+							   WE_SYSLOGGER_MAIN);
 
 		if (rc & WL_SOCKET_READABLE)
 		{
@@ -475,7 +476,8 @@ SysLoggerMain(int argc, char *argv[])
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | cur_flags,
-						 cur_timeout);
+						 cur_timeout,
+						 EVENT_SYSLOGGER_MAIN);
 
 		EnterCriticalSection(&sysloggerSection);
 #endif   /* WIN32 */
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index 11ec56a..5b6fa15 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -290,7 +290,8 @@ WalWriterMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout);
+					   cur_timeout,
+					   WE_WAL_WRITER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index da9b7a6..82e8d03 100644
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -1286,7 +1286,8 @@ throttle(size_t increment)
 		 */
 		wait_result = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								(long) (sleep / 1000));
+								(long) (sleep / 1000),
+								WE_BASE_BACKUP_THROTTLE);
 
 		if (wait_result & WL_LATCH_SET)
 			CHECK_FOR_INTERRUPTS();
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index b442d06..f1acb4a 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -258,7 +258,8 @@ SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
 		 * Wait on latch.  Any condition that should wake us up will set the
 		 * latch, so no need for timeout.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1);
+		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1,
+				  WE_SYNC_REP);
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 413ee3a..046a760 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -486,7 +486,8 @@ WalReceiverMain(void)
 								   WL_POSTMASTER_DEATH | WL_SOCKET_READABLE |
 									   WL_TIMEOUT | WL_LATCH_SET,
 									   wait_fd,
-									   NAPTIME_PER_CYCLE);
+									   NAPTIME_PER_CYCLE,
+									   WE_WAL_RECEIVER_MAIN);
 				if (rc & WL_LATCH_SET)
 				{
 					ResetLatch(&walrcv->latch);
@@ -685,7 +686,8 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 		}
 		SpinLockRelease(&walrcv->mutex);
 
-		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+				  WE_WAL_RECEIVER_WAIT_START);
 	}
 
 	if (update_process_title)
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index c7743da..3cac83b 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -1146,7 +1146,8 @@ WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid,
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  WE_WAL_SENDER_WRITE_DATA);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1272,7 +1273,8 @@ WalSndWaitForWal(XLogRecPtr loc)
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  WE_WAL_SENDER_WAIT_WAL);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1924,7 +1926,8 @@ WalSndLoop(WalSndSendDataCallback send_data)
 
 			/* Sleep until something happens or we time out */
 			WaitLatchOrSocket(MyLatch, wakeEvents,
-							  MyProcPort->sock, sleeptime);
+							  MyProcPort->sock, sleeptime,
+							  WE_WAL_SENDER_MAIN);
 		}
 	}
 	return;
diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c
index 9def8a1..3394238 100644
--- a/src/backend/storage/ipc/latch.c
+++ b/src/backend/storage/ipc/latch.c
@@ -55,6 +55,7 @@
 #endif
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "portability/instr_time.h"
 #include "postmaster/postmaster.h"
 #include "storage/barrier.h"
@@ -122,6 +123,46 @@ struct WaitEventSet
 #endif
 };
 
+/*
+ * This must match enum WaitEventIdentifier! The alphabetical order here
+ * is kept in priority and in-sync with the documentation.
+ */
+const char *const WaitEventNames[] = {
+	"ArchiverMain",
+	"AutoVacuumMain",
+	"BaseBackupThrottle",
+	"BgWorkerShutdown",
+	"BgWorkerStartup",
+	"BgWriterHibernate",
+	"BgWriterMain",
+	"CheckpointerMain",
+	"ExecuteGather",
+	"Extension",
+	"MessageQueueInternal",
+	"MessageQueuePutMessage",
+	"MessageQueueReceive",
+	"MessageQueueSend",
+	"ParallelFinish",
+	"PgSleep",
+	"PgStatMain",
+	"ProcSignal",
+	"ProcSleep",
+	"RecoveryApplyDelay",
+	"RecoveryWalAll",
+	"RecoveryWalStream",
+	"SecureRead",
+	"SecureWrite",
+	"SSLOpenServer",
+	"SyncRep",
+	"SysLoggerMain",
+	"WalReceiverMain",
+	"WalReceiverWaitStart",
+	"WalSenderMain",
+	"WalSenderWaitForWAL",
+	"WalSenderWriteData",
+	"WalWriterMain"
+};
+
 #ifndef WIN32
 /* Are we currently in WaitLatch? The signal handler would like to know. */
 static volatile sig_atomic_t waiting = false;
@@ -297,9 +338,11 @@ DisownLatch(volatile Latch *latch)
  * we return all of them in one call, but we will return at least one.
  */
 int
-WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
+WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+		  WaitEventIdentifier eventId)
 {
-	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout);
+	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout,
+							 eventId);
 }
 
 /*
@@ -316,7 +359,7 @@ WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
  */
 int
 WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
-				  long timeout)
+				  long timeout, WaitEventIdentifier eventId)
 {
 	int			ret = 0;
 	int			rc;
@@ -344,7 +387,7 @@ WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
 		AddWaitEventToSet(set, ev, sock, NULL, NULL);
 	}
 
-	rc = WaitEventSetWait(set, timeout, &event, 1);
+	rc = WaitEventSetWait(set, timeout, &event, 1, eventId);
 
 	if (rc == 0)
 		ret |= WL_TIMEOUT;
@@ -863,7 +906,8 @@ WaitEventAdjustWin32(WaitEventSet *set, WaitEvent *event)
  */
 int
 WaitEventSetWait(WaitEventSet *set, long timeout,
-				 WaitEvent *occurred_events, int nevents)
+				 WaitEvent *occurred_events, int nevents,
+				 WaitEventIdentifier eventId)
 {
 	int			returned_events = 0;
 	instr_time	start_time;
@@ -872,6 +916,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 
 	Assert(nevents > 0);
 
+	pgstat_report_wait_start(WAIT_EVENT_SET, (uint16) eventId);
+
 	/*
 	 * Initialize timeout if requested.  We must record the current time so
 	 * that we can determine the remaining timeout if interrupted.
@@ -960,6 +1006,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 	waiting = false;
 #endif
 
+	pgstat_report_wait_end();
+
 	return returned_events;
 }
 
@@ -1491,6 +1539,20 @@ WaitEventSetWaitBlock(WaitEventSet *set, int cur_timeout,
 }
 #endif
 
+
+/*
+ * Return an identifier for a Latch depending on an event for statistics
+ * collector.
+ */
+const char *
+GetWaitEventIdentifier(uint16 eventId)
+{
+	if (eventId > WE_LAST_TYPE)
+		return "???";
+	return WaitEventNames[eventId];
+}
+
+
 /*
  * SetLatch uses SIGUSR1 to wake up the process waiting on the latch.
  *
diff --git a/src/backend/storage/ipc/shm_mq.c b/src/backend/storage/ipc/shm_mq.c
index 5b32782..c47cf2b 100644
--- a/src/backend/storage/ipc/shm_mq.c
+++ b/src/backend/storage/ipc/shm_mq.c
@@ -894,7 +894,7 @@ shm_mq_send_bytes(shm_mq_handle *mqh, Size nbytes, const void *data,
 			 * at top of loop, because setting an already-set latch is much
 			 * cheaper than setting one that has been reset.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_MQ_SEND);
 
 			/* Reset the latch so we don't spin. */
 			ResetLatch(MyLatch);
@@ -991,7 +991,7 @@ shm_mq_receive_bytes(shm_mq *mq, Size bytes_needed, bool nowait,
 		 * loop, because setting an already-set latch is much cheaper than
 		 * setting one that has been reset.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_MQ_RECEIVE);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
@@ -1090,7 +1090,7 @@ shm_mq_wait_internal(volatile shm_mq *mq, PGPROC *volatile * ptr,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_MQ_INTERNAL);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 33e7023..23deeb6 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -1212,7 +1212,7 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
 		}
 		else
 		{
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_PROC_SLEEP);
 			ResetLatch(MyLatch);
 			/* check for deadlocks first, as that's probably log-worthy */
 			if (got_deadlock_timeout)
@@ -1724,7 +1724,7 @@ CheckDeadLockAlert(void)
 void
 ProcWaitForSignal(void)
 {
-	WaitLatch(MyLatch, WL_LATCH_SET, 0);
+	WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_PROC_SIGNAL);
 	ResetLatch(MyLatch);
 	CHECK_FOR_INTERRUPTS();
 }
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 5e705e9..a814a06 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -560,7 +560,7 @@ pg_sleep(PG_FUNCTION_ARGS)
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | WL_TIMEOUT,
-						 delay_ms);
+						 delay_ms, WE_PG_SLEEP);
 		ResetLatch(MyLatch);
 	}
 
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index dc3320d..bca16e4 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -721,7 +721,8 @@ typedef enum WaitClass
 	WAIT_LWLOCK_NAMED,
 	WAIT_LWLOCK_TRANCHE,
 	WAIT_LOCK,
-	WAIT_BUFFER_PIN
+	WAIT_BUFFER_PIN,
+	WAIT_EVENT_SET
 }	WaitClass;
 
 
diff --git a/src/include/storage/latch.h b/src/include/storage/latch.h
index 5179ecc..45859bb 100644
--- a/src/include/storage/latch.h
+++ b/src/include/storage/latch.h
@@ -135,6 +135,51 @@ typedef struct WaitEvent
 	void	   *user_data;		/* pointer provided in AddWaitEventToSet */
 } WaitEvent;
 
+/*
+ * List of latch identifiers used when reporting activity to statistics
+ * collector. Up to 256 different WaitEventIdentifier can be handled.
+ */
+typedef enum WaitEventIdentifier
+{
+	WE_ARCHIVER_MAIN,
+	WE_AUTOVACUUM_MAIN,
+	WE_BASE_BACKUP_THROTTLE,
+	WE_BGWORKER_SHUTDOWN,
+	WE_BGWORKER_STARTUP,
+	WE_BGWRITER_HIBERNATE,
+	WE_BGWRITER_MAIN,
+	WE_CHECKPOINTER_MAIN,
+	WE_EXECUTE_GATHER,
+	WE_EXTENSION,
+	WE_MQ_INTERNAL,
+	WE_MQ_PUT_MESSAGE,
+	WE_MQ_RECEIVE,
+	WE_MQ_SEND,
+	WE_PARALLEL_FINISH,
+	WE_PG_SLEEP,
+	WE_PGSTAT_MAIN,
+	WE_PROC_SIGNAL,
+	WE_PROC_SLEEP,
+	WE_RECOVERY_APPLY_DELAY,
+	WE_RECOVERY_WAL_ALL,
+	WE_RECOVERY_WAL_STREAM,
+	WE_SECURE_READ,
+	WE_SECURE_WRITE,
+	WE_SSL_OPEN_SERVER,
+	WE_SYNC_REP,
+	WE_SYSLOGGER_MAIN,
+	WE_WAL_RECEIVER_MAIN,
+	WE_WAL_RECEIVER_WAIT_START,
+	WE_WAL_SENDER_MAIN,
+	WE_WAL_SENDER_WAIT_WAL,
+	WE_WAL_SENDER_WRITE_DATA,
+	WE_WAL_WRITER_MAIN
+} WaitEventIdentifier;
+
+#define WE_LAST_TYPE WE_WAL_WRITER_MAIN
+
+extern const char *const WaitEventName[];
+
 /* forward declaration to avoid exposing latch.c implementation details */
 typedef struct WaitEventSet WaitEventSet;
 
@@ -155,10 +200,14 @@ extern int AddWaitEventToSet(WaitEventSet *set, uint32 events, pgsocket fd,
 				  Latch *latch, void *user_data);
 extern void ModifyWaitEvent(WaitEventSet *set, int pos, uint32 events, Latch *latch);
 
-extern int	WaitEventSetWait(WaitEventSet *set, long timeout, WaitEvent *occurred_events, int nevents);
-extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout);
+extern int	WaitEventSetWait(WaitEventSet *set, long timeout,
+				  WaitEvent *occurred_events, int nevents,
+				  WaitEventIdentifier eventId);
+extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+				  WaitEventIdentifier eventId);
 extern int WaitLatchOrSocket(volatile Latch *latch, int wakeEvents,
-				  pgsocket sock, long timeout);
+				  pgsocket sock, long timeout, WaitEventIdentifier eventId);
+extern const char *GetWaitEventIdentifier(uint16 eventId);
 
 /*
  * Unix implementation uses SIGUSR1 for inter-process signaling.
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 143df4e..adebfc8 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -279,7 +279,7 @@ wait_for_workers_to_become_ready(worker_state *wstate,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_EXTENSION);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/test/modules/test_shm_mq/test.c b/src/test/modules/test_shm_mq/test.c
index dd34bc7..22145db 100644
--- a/src/test/modules/test_shm_mq/test.c
+++ b/src/test/modules/test_shm_mq/test.c
@@ -230,7 +230,7 @@ test_shm_mq_pipelined(PG_FUNCTION_ARGS)
 			 * have read or written data and therefore there may now be work
 			 * for us to do.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_EXTENSION);
 			ResetLatch(MyLatch);
 			CHECK_FOR_INTERRUPTS();
 		}
diff --git a/src/test/modules/worker_spi/worker_spi.c b/src/test/modules/worker_spi/worker_spi.c
index 314e371..aa7f7f9 100644
--- a/src/test/modules/worker_spi/worker_spi.c
+++ b/src/test/modules/worker_spi/worker_spi.c
@@ -227,7 +227,8 @@ worker_spi_main(Datum main_arg)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   worker_spi_naptime * 1000L);
+					   worker_spi_naptime * 1000L,
+					   WE_EXTENSION);
 		ResetLatch(MyLatch);
 
 		/* emergency bailout if postmaster has died */

diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 8ca1c1c..7cecef8 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -496,7 +496,7 @@ pgfdw_get_result(PGconn *conn, const char *query)
 			wc = WaitLatchOrSocket(MyLatch,
 								   WL_LATCH_SET | WL_SOCKET_READABLE,
 								   PQsocket(conn),
-								   -1L);
+								   -1L, WE_EXTENSION);
 			ResetLatch(MyLatch);
 
 			CHECK_FOR_INTERRUPTS();
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 0776428..5185d65 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -679,6 +679,18 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
           buffer in question.
          </para>
         </listitem>
+        <listitem>
+         <para>
+          <literal>EventSet</>: The server process is waiting on one or more
+          sockets, a time or an inter-process latch.  The wait happens in a
+          <function>WaitEventSet</>, <productname>PostgreSQL</>'s portable
+          I/O multiplexing abstraction using boolean variables letting a
+          process sleep until it is set.  It supports several type of
+          operations, like postmaster death handling, timeout and socket
+          activity lookup, and are a useful replacement for <function>sleep</>
+          where signal handling matters.
+         </para>
+        </listitem>
        </itemizedlist>
       </entry>
      </row>
@@ -1085,6 +1097,139 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
          <entry><literal>BufferPin</></entry>
          <entry>Waiting to acquire a pin on a buffer.</entry>
         </row>
+        <row>
+         <entry morerows="32"><literal>EventSet</></entry>
+         <entry><literal>ArchiverMain</></entry>
+         <entry>Waiting in main loop of the archiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>AutoVacuumMain</></entry>
+         <entry>Waiting in main loop of autovacuum launcher process.</entry>
+        </row>
+        <row>
+         <entry><literal>BaseBackupThrottle</></entry>
+         <entry>Waiting during base backup when throttling activity.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWorkerShutdown</></entry>
+         <entry>Waiting for background worker to shut down.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWorkerStartup</></entry>
+         <entry>Waiting for background worker to start up.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterHibernate</></entry>
+         <entry>Waiting in background writer process, hibernating.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterMain</></entry>
+         <entry>Waiting in main loop of background writer process background worker.</entry>
+        </row>
+        <row>
+         <entry><literal>CheckpointerMain</></entry>
+         <entry>Waiting in main loop of checkpointer process.</entry>
+        </row>
+        <row>
+         <entry><literal>ExecuteGather</></entry>
+         <entry>Waiting for activity from child process when executing <literal>Gather</> node.</entry>
+        </row>
+        <row>
+         <entry><literal>Extension</></entry>
+         <entry>Waiting in the code path of an extension, should be used by custom plugins and modules</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueInternal</></entry>
+         <entry>Waiting for other process to be attached in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueuePutMessage</></entry>
+         <entry>Waiting to put new message in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueReceive</></entry>
+         <entry>Waiting to receive bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueSend</></entry>
+         <entry>Waiting to send bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>ParallelFinish</></entry>
+         <entry>Waiting for parallel workers to finish computing.</entry>
+        </row>
+        <row>
+         <entry><literal>PgSleep</></entry>
+         <entry>Waiting in process that called <function>pg_sleep</>.</entry>
+        </row>
+        <row>
+         <entry><literal>PgStatMain</></entry>
+         <entry>Waiting in main loop of the statistics collector process.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSignal</></entry>
+         <entry>Waiting for signal from another backend.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSleep</></entry>
+         <entry>Waiting for a specific lock.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryApplyDelay</></entry>
+         <entry>Waiting to apply WAL at recovery because it is delayed.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalAll</></entry>
+         <entry>Waiting for WAL from any kind of source (local, archive or stream) at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalStream</></entry>
+         <entry>Waiting for WAL from a stream at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>SecureRead</></entry>
+         <entry>Waiting to read data from a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SecureWrite</></entry>
+         <entry>Waiting to write data to a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SSLOpenServer</></entry>
+         <entry>Waiting for SSL while attempting connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SyncRep</></entry>
+         <entry>Waiting for WAL commit during synchronous replication.</entry>
+        </row>
+        <row>
+         <entry><literal>SysLoggerMain</></entry>
+         <entry>Waiting in main loop of syslogger process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverMain</></entry>
+         <entry>Waiting in main loop of WAL receiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverWaitStart</></entry>
+         <entry>Waiting for startup process to send initial data for streaming replication.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderMain</></entry>
+         <entry>Waiting in main loop of WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWaitForWAL</></entry>
+         <entry>Waiting for WAL to be flushed in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWriteData</></entry>
+         <entry>Waiting for any activity when processing replies from WAL receiver in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalWriterMain</></entry>
+         <entry>Waiting in main loop of WAL writer process.</entry>
+        </row>
       </tbody>
      </tgroup>
     </table>
diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c
index cde0ed3..60d5c9c 100644
--- a/src/backend/access/transam/parallel.c
+++ b/src/backend/access/transam/parallel.c
@@ -540,7 +540,8 @@ WaitForParallelWorkersToFinish(ParallelContext *pcxt)
 		if (!anyone_alive)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1,
+				  WE_PARALLEL_FINISH);
 		ResetLatch(&MyProc->procLatch);
 	}
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 2189c22..678b6de 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5827,7 +5827,8 @@ recoveryApplyDelay(XLogReaderState *record)
 
 		WaitLatch(&XLogCtl->recoveryWakeupLatch,
 				  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-				  secs * 1000L + microsecs / 1000);
+				  secs * 1000L + microsecs / 1000,
+				  WE_RECOVERY_APPLY_DELAY);
 	}
 	return true;
 }
@@ -11376,7 +11377,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 
 						WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								  wait_time);
+							 wait_time, WE_RECOVERY_WAL_STREAM);
 						ResetLatch(&XLogCtl->recoveryWakeupLatch);
 						now = GetCurrentTimestamp();
 					}
@@ -11539,7 +11540,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					 */
 					WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							  5000L);
+							  5000L, WE_RECOVERY_WAL_ALL);
 					ResetLatch(&XLogCtl->recoveryWakeupLatch);
 					break;
 				}
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 438d1b2..b832d91 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -387,7 +387,7 @@ gather_readnext(GatherState *gatherstate)
 				return NULL;
 
 			/* Nothing to do except wait for developments. */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_EXECUTE_GATHER);
 			ResetLatch(MyLatch);
 			nvisited = 0;
 		}
diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
index fedb02c..571d4d6 100644
--- a/src/backend/libpq/be-secure-openssl.c
+++ b/src/backend/libpq/be-secure-openssl.c
@@ -419,7 +419,8 @@ aloop:
 				else
 					waitfor = WL_SOCKET_WRITEABLE;
 
-				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0);
+				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0,
+								  WE_SSL_OPEN_SERVER);
 				goto aloop;
 			case SSL_ERROR_SYSCALL:
 				if (r < 0)
diff --git a/src/backend/libpq/be-secure.c b/src/backend/libpq/be-secure.c
index cdd07d5..4e16073 100644
--- a/src/backend/libpq/be-secure.c
+++ b/src/backend/libpq/be-secure.c
@@ -146,7 +146,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 WE_SECURE_READ);
 
 		/*
 		 * If the postmaster has died, it's not safe to continue running,
@@ -247,7 +248,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 WE_SECURE_WRITE);
 
 		/* See comments in secure_read. */
 		if (event.events & WL_POSTMASTER_DEATH)
diff --git a/src/backend/libpq/pqmq.c b/src/backend/libpq/pqmq.c
index bfe66c6..625b987 100644
--- a/src/backend/libpq/pqmq.c
+++ b/src/backend/libpq/pqmq.c
@@ -171,7 +171,7 @@ mq_putmessage(char msgtype, const char *s, size_t len)
 		if (result != SHM_MQ_WOULD_BLOCK)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0, WE_MQ_PUT_MESSAGE);
 		ResetLatch(&MyProc->procLatch);
 		CHECK_FOR_INTERRUPTS();
 	}
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 1a92ca1..019075e 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -598,7 +598,8 @@ AutoVacLauncherMain(int argc, char *argv[])
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L));
+					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L),
+					   WE_AUTOVACUUM_MAIN);
 
 		ResetLatch(MyLatch);
 
diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c
index 699c934..7da01df 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -969,7 +969,8 @@ WaitForBackgroundWorkerStartup(BackgroundWorkerHandle *handle, pid_t *pidp)
 			break;
 
 		rc = WaitLatch(MyLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   WE_BGWORKER_STARTUP);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
@@ -1008,7 +1009,8 @@ WaitForBackgroundWorkerShutdown(BackgroundWorkerHandle *handle)
 			break;
 
 		rc = WaitLatch(&MyProc->procLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   WE_BGWORKER_SHUTDOWN);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index 1002034..a89d39d 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -345,7 +345,8 @@ BackgroundWriterMain(void)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   BgWriterDelay /* ms */ );
+					   BgWriterDelay /* ms */,
+					   WE_BGWRITER_MAIN);
 
 		/*
 		 * If no latch event and BgBufferSync says nothing's happening, extend
@@ -372,7 +373,8 @@ BackgroundWriterMain(void)
 			/* Sleep ... */
 			rc = WaitLatch(MyLatch,
 						   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-						   BgWriterDelay * HIBERNATE_FACTOR);
+						   BgWriterDelay * HIBERNATE_FACTOR,
+						   WE_BGWRITER_HIBERNATE);
 			/* Reset the notification request in case we timed out */
 			StrategyNotifyBgWriter(-1);
 		}
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index d702a48..e18ef9f 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -556,7 +556,8 @@ CheckpointerMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout * 1000L /* convert to ms */ );
+					   cur_timeout * 1000L /* convert to ms */,
+					   WE_CHECKPOINTER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 1aa6466..018878c 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -390,7 +390,7 @@ pgarch_MainLoop(void)
 
 				rc = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							   timeout * 1000L);
+							 timeout * 1000L, WE_ARCHIVER_MAIN);
 				if (rc & WL_TIMEOUT)
 					wakened = true;
 			}
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 8a2ce91..ca1b129 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -3152,6 +3152,9 @@ pgstat_get_wait_event_type(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_type = "BufferPin";
 			break;
+		case WAIT_EVENT_SET:
+			event_type = "EventSet";
+			break;
 		default:
 			event_type = "???";
 			break;
@@ -3193,6 +3196,9 @@ pgstat_get_wait_event(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_name = "BufferPin";
 			break;
+		case WAIT_EVENT_SET:
+			event_name = GetWaitEventIdentifier(eventId);
+			break;
 		default:
 			event_name = "unknown wait event";
 			break;
@@ -3682,7 +3688,7 @@ PgstatCollectorMain(int argc, char *argv[])
 		wr = WaitLatchOrSocket(MyLatch,
 					 WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE,
 							   pgStatSock,
-							   -1L);
+							   -1L, WE_PGSTAT_MAIN);
 #else
 
 		/*
@@ -3698,7 +3704,8 @@ PgstatCollectorMain(int argc, char *argv[])
 		wr = WaitLatchOrSocket(MyLatch,
 		WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE | WL_TIMEOUT,
 							   pgStatSock,
-							   2 * 1000L /* msec */ );
+							   2 * 1000L /* msec */,
+							   WE_PGSTAT_MAIN);
 #endif
 
 		/*
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index e7e488a..c081224 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -424,7 +424,8 @@ SysLoggerMain(int argc, char *argv[])
 		rc = WaitLatchOrSocket(MyLatch,
 							   WL_LATCH_SET | WL_SOCKET_READABLE | cur_flags,
 							   syslogPipe[0],
-							   cur_timeout);
+							   cur_timeout,
+							   WE_SYSLOGGER_MAIN);
 
 		if (rc & WL_SOCKET_READABLE)
 		{
@@ -475,7 +476,8 @@ SysLoggerMain(int argc, char *argv[])
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | cur_flags,
-						 cur_timeout);
+						 cur_timeout,
+						 WE_SYSLOGGER_MAIN);
 
 		EnterCriticalSection(&sysloggerSection);
 #endif   /* WIN32 */
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index 11ec56a..5b6fa15 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -290,7 +290,8 @@ WalWriterMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout);
+					   cur_timeout,
+					   WE_WAL_WRITER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index da9b7a6..82e8d03 100644
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -1286,7 +1286,8 @@ throttle(size_t increment)
 		 */
 		wait_result = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								(long) (sleep / 1000));
+								(long) (sleep / 1000),
+								WE_BASE_BACKUP_THROTTLE);
 
 		if (wait_result & WL_LATCH_SET)
 			CHECK_FOR_INTERRUPTS();
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index b442d06..f1acb4a 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -258,7 +258,8 @@ SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
 		 * Wait on latch.  Any condition that should wake us up will set the
 		 * latch, so no need for timeout.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1);
+		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1,
+				  WE_SYNC_REP);
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 413ee3a..046a760 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -486,7 +486,8 @@ WalReceiverMain(void)
 								   WL_POSTMASTER_DEATH | WL_SOCKET_READABLE |
 									   WL_TIMEOUT | WL_LATCH_SET,
 									   wait_fd,
-									   NAPTIME_PER_CYCLE);
+									   NAPTIME_PER_CYCLE,
+									   WE_WAL_RECEIVER_MAIN);
 				if (rc & WL_LATCH_SET)
 				{
 					ResetLatch(&walrcv->latch);
@@ -685,7 +686,8 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 		}
 		SpinLockRelease(&walrcv->mutex);
 
-		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+				  WE_WAL_RECEIVER_WAIT_START);
 	}
 
 	if (update_process_title)
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index c7743da..3cac83b 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -1146,7 +1146,8 @@ WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid,
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  WE_WAL_SENDER_WRITE_DATA);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1272,7 +1273,8 @@ WalSndWaitForWal(XLogRecPtr loc)
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  WE_WAL_SENDER_WAIT_WAL);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1924,7 +1926,8 @@ WalSndLoop(WalSndSendDataCallback send_data)
 
 			/* Sleep until something happens or we time out */
 			WaitLatchOrSocket(MyLatch, wakeEvents,
-							  MyProcPort->sock, sleeptime);
+							  MyProcPort->sock, sleeptime,
+							  WE_WAL_SENDER_MAIN);
 		}
 	}
 	return;
diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c
index 9def8a1..57590ac 100644
--- a/src/backend/storage/ipc/latch.c
+++ b/src/backend/storage/ipc/latch.c
@@ -55,6 +55,7 @@
 #endif
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "portability/instr_time.h"
 #include "postmaster/postmaster.h"
 #include "storage/barrier.h"
@@ -122,6 +123,46 @@ struct WaitEventSet
 #endif
 };
 
+/*
+ * This must match enum WaitEventIdentifier! The alphabetical order here
+ * is kept in priority and in-sync with the documentation.
+ */
+const char *const WaitEventNames[] = {
+	"ArchiverMain",
+	"AutoVacuumMain",
+	"BaseBackupThrottle",
+	"BgWorkerShutdown",
+	"BgWorkerStartup",
+	"BgWriterHibernate",
+	"BgWriterMain",
+	"CheckpointerMain",
+	"ExecuteGather",
+	"Extension",
+	"MessageQueueInternal",
+	"MessageQueuePutMessage",
+	"MessageQueueReceive",
+	"MessageQueueSend",
+	"ParallelFinish",
+	"PgSleep",
+	"PgStatMain",
+	"ProcSignal",
+	"ProcSleep",
+	"RecoveryApplyDelay",
+	"RecoveryWalAll",
+	"RecoveryWalStream",
+	"SecureRead",
+	"SecureWrite",
+	"SSLOpenServer",
+	"SyncRep",
+	"SysLoggerMain",
+	"WalReceiverMain",
+	"WalReceiverWaitStart",
+	"WalSenderMain",
+	"WalSenderWaitForWAL",
+	"WalSenderWriteData",
+	"WalWriterMain"
+};
+
 #ifndef WIN32
 /* Are we currently in WaitLatch? The signal handler would like to know. */
 static volatile sig_atomic_t waiting = false;
@@ -297,9 +338,11 @@ DisownLatch(volatile Latch *latch)
  * we return all of them in one call, but we will return at least one.
  */
 int
-WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
+WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+		  WaitEventIdentifier eventId)
 {
-	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout);
+	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout,
+							 eventId);
 }
 
 /*
@@ -316,7 +359,7 @@ WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
  */
 int
 WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
-				  long timeout)
+				  long timeout, WaitEventIdentifier eventId)
 {
 	int			ret = 0;
 	int			rc;
@@ -344,7 +387,7 @@ WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
 		AddWaitEventToSet(set, ev, sock, NULL, NULL);
 	}
 
-	rc = WaitEventSetWait(set, timeout, &event, 1);
+	rc = WaitEventSetWait(set, timeout, &event, 1, eventId);
 
 	if (rc == 0)
 		ret |= WL_TIMEOUT;
@@ -863,7 +906,8 @@ WaitEventAdjustWin32(WaitEventSet *set, WaitEvent *event)
  */
 int
 WaitEventSetWait(WaitEventSet *set, long timeout,
-				 WaitEvent *occurred_events, int nevents)
+				 WaitEvent *occurred_events, int nevents,
+				 WaitEventIdentifier eventId)
 {
 	int			returned_events = 0;
 	instr_time	start_time;
@@ -872,6 +916,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 
 	Assert(nevents > 0);
 
+	pgstat_report_wait_start(WAIT_EVENT_SET, (uint16) eventId);
+
 	/*
 	 * Initialize timeout if requested.  We must record the current time so
 	 * that we can determine the remaining timeout if interrupted.
@@ -960,6 +1006,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 	waiting = false;
 #endif
 
+	pgstat_report_wait_end();
+
 	return returned_events;
 }
 
@@ -1491,6 +1539,22 @@ WaitEventSetWaitBlock(WaitEventSet *set, int cur_timeout,
 }
 #endif
 
+
+/*
+ * Return an identifier for a Latch depending on an event for statistics
+ * collector.
+ */
+const char *
+GetWaitEventIdentifier(uint16 eventId)
+{
+	StaticAssertStmt(lengthof(WaitEventNames) == WE_LAST_TYPE + 1,
+					 "WaitEventNames must match WaitEventIdentifiers");
+	if (eventId > WE_LAST_TYPE)
+		return "???";
+	return WaitEventNames[eventId];
+}
+
+
 /*
  * SetLatch uses SIGUSR1 to wake up the process waiting on the latch.
  *
diff --git a/src/backend/storage/ipc/shm_mq.c b/src/backend/storage/ipc/shm_mq.c
index 5b32782..c47cf2b 100644
--- a/src/backend/storage/ipc/shm_mq.c
+++ b/src/backend/storage/ipc/shm_mq.c
@@ -894,7 +894,7 @@ shm_mq_send_bytes(shm_mq_handle *mqh, Size nbytes, const void *data,
 			 * at top of loop, because setting an already-set latch is much
 			 * cheaper than setting one that has been reset.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_MQ_SEND);
 
 			/* Reset the latch so we don't spin. */
 			ResetLatch(MyLatch);
@@ -991,7 +991,7 @@ shm_mq_receive_bytes(shm_mq *mq, Size bytes_needed, bool nowait,
 		 * loop, because setting an already-set latch is much cheaper than
 		 * setting one that has been reset.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_MQ_RECEIVE);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
@@ -1090,7 +1090,7 @@ shm_mq_wait_internal(volatile shm_mq *mq, PGPROC *volatile * ptr,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_MQ_INTERNAL);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 33e7023..23deeb6 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -1212,7 +1212,7 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
 		}
 		else
 		{
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_PROC_SLEEP);
 			ResetLatch(MyLatch);
 			/* check for deadlocks first, as that's probably log-worthy */
 			if (got_deadlock_timeout)
@@ -1724,7 +1724,7 @@ CheckDeadLockAlert(void)
 void
 ProcWaitForSignal(void)
 {
-	WaitLatch(MyLatch, WL_LATCH_SET, 0);
+	WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_PROC_SIGNAL);
 	ResetLatch(MyLatch);
 	CHECK_FOR_INTERRUPTS();
 }
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 5e705e9..a814a06 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -560,7 +560,7 @@ pg_sleep(PG_FUNCTION_ARGS)
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | WL_TIMEOUT,
-						 delay_ms);
+						 delay_ms, WE_PG_SLEEP);
 		ResetLatch(MyLatch);
 	}
 
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index dc3320d..bca16e4 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -721,7 +721,8 @@ typedef enum WaitClass
 	WAIT_LWLOCK_NAMED,
 	WAIT_LWLOCK_TRANCHE,
 	WAIT_LOCK,
-	WAIT_BUFFER_PIN
+	WAIT_BUFFER_PIN,
+	WAIT_EVENT_SET
 }	WaitClass;
 
 
diff --git a/src/include/storage/latch.h b/src/include/storage/latch.h
index 5179ecc..45859bb 100644
--- a/src/include/storage/latch.h
+++ b/src/include/storage/latch.h
@@ -135,6 +135,51 @@ typedef struct WaitEvent
 	void	   *user_data;		/* pointer provided in AddWaitEventToSet */
 } WaitEvent;
 
+/*
+ * List of latch identifiers used when reporting activity to statistics
+ * collector. Up to 256 different WaitEventIdentifier can be handled.
+ */
+typedef enum WaitEventIdentifier
+{
+	WE_ARCHIVER_MAIN,
+	WE_AUTOVACUUM_MAIN,
+	WE_BASE_BACKUP_THROTTLE,
+	WE_BGWORKER_SHUTDOWN,
+	WE_BGWORKER_STARTUP,
+	WE_BGWRITER_HIBERNATE,
+	WE_BGWRITER_MAIN,
+	WE_CHECKPOINTER_MAIN,
+	WE_EXECUTE_GATHER,
+	WE_EXTENSION,
+	WE_MQ_INTERNAL,
+	WE_MQ_PUT_MESSAGE,
+	WE_MQ_RECEIVE,
+	WE_MQ_SEND,
+	WE_PARALLEL_FINISH,
+	WE_PG_SLEEP,
+	WE_PGSTAT_MAIN,
+	WE_PROC_SIGNAL,
+	WE_PROC_SLEEP,
+	WE_RECOVERY_APPLY_DELAY,
+	WE_RECOVERY_WAL_ALL,
+	WE_RECOVERY_WAL_STREAM,
+	WE_SECURE_READ,
+	WE_SECURE_WRITE,
+	WE_SSL_OPEN_SERVER,
+	WE_SYNC_REP,
+	WE_SYSLOGGER_MAIN,
+	WE_WAL_RECEIVER_MAIN,
+	WE_WAL_RECEIVER_WAIT_START,
+	WE_WAL_SENDER_MAIN,
+	WE_WAL_SENDER_WAIT_WAL,
+	WE_WAL_SENDER_WRITE_DATA,
+	WE_WAL_WRITER_MAIN
+} WaitEventIdentifier;
+
+#define WE_LAST_TYPE WE_WAL_WRITER_MAIN
+
+extern const char *const WaitEventName[];
+
 /* forward declaration to avoid exposing latch.c implementation details */
 typedef struct WaitEventSet WaitEventSet;
 
@@ -155,10 +200,14 @@ extern int AddWaitEventToSet(WaitEventSet *set, uint32 events, pgsocket fd,
 				  Latch *latch, void *user_data);
 extern void ModifyWaitEvent(WaitEventSet *set, int pos, uint32 events, Latch *latch);
 
-extern int	WaitEventSetWait(WaitEventSet *set, long timeout, WaitEvent *occurred_events, int nevents);
-extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout);
+extern int	WaitEventSetWait(WaitEventSet *set, long timeout,
+				  WaitEvent *occurred_events, int nevents,
+				  WaitEventIdentifier eventId);
+extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+				  WaitEventIdentifier eventId);
 extern int WaitLatchOrSocket(volatile Latch *latch, int wakeEvents,
-				  pgsocket sock, long timeout);
+				  pgsocket sock, long timeout, WaitEventIdentifier eventId);
+extern const char *GetWaitEventIdentifier(uint16 eventId);
 
 /*
  * Unix implementation uses SIGUSR1 for inter-process signaling.
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 143df4e..adebfc8 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -279,7 +279,7 @@ wait_for_workers_to_become_ready(worker_state *wstate,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_EXTENSION);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/test/modules/test_shm_mq/test.c b/src/test/modules/test_shm_mq/test.c
index dd34bc7..22145db 100644
--- a/src/test/modules/test_shm_mq/test.c
+++ b/src/test/modules/test_shm_mq/test.c
@@ -230,7 +230,7 @@ test_shm_mq_pipelined(PG_FUNCTION_ARGS)
 			 * have read or written data and therefore there may now be work
 			 * for us to do.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_EXTENSION);
 			ResetLatch(MyLatch);
 			CHECK_FOR_INTERRUPTS();
 		}
diff --git a/src/test/modules/worker_spi/worker_spi.c b/src/test/modules/worker_spi/worker_spi.c
index 314e371..aa7f7f9 100644
--- a/src/test/modules/worker_spi/worker_spi.c
+++ b/src/test/modules/worker_spi/worker_spi.c
@@ -227,7 +227,8 @@ worker_spi_main(Datum main_arg)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   worker_spi_naptime * 1000L);
+					   worker_spi_naptime * 1000L,
+					   WE_EXTENSION);
 		ResetLatch(MyLatch);
 
 		/* emergency bailout if postmaster has died */

diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 8ca1c1c..9222b73 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -17,6 +17,7 @@
 #include "access/xact.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "storage/latch.h"
 #include "utils/hsearch.h"
 #include "utils/memutils.h"
@@ -496,7 +497,9 @@ pgfdw_get_result(PGconn *conn, const char *query)
 			wc = WaitLatchOrSocket(MyLatch,
 								   WL_LATCH_SET | WL_SOCKET_READABLE,
 								   PQsocket(conn),
-								   -1L);
+								   -1L,
+								   WAIT_EXTENSION,
+								   WE_EXTENSION);
 			ResetLatch(MyLatch);
 
 			CHECK_FOR_INTERRUPTS();
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 0776428..6f7eef9 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -679,6 +679,44 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
           buffer in question.
          </para>
         </listitem>
+        <listitem>
+         <para>
+          <literal>Activity</>: The server process is waiting for some
+          activity to happen on a socket.  This is mainly used system processes
+          in their main processing loop.  <literal>wait_event</> will identify
+          the type of activity waited for.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Extension</>: The server process is waiting for activity
+          in a plugin or an extension.  This category is useful for plugin
+          and module developers to track custom waiting points.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Client</>: The server process is waiting for some activity
+          on a socket from a client process, and that the server expects
+          something to happen that is independent from its internal processes.
+          <literal>wait_event</> will identify the type of client activity
+          waited for.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>IPC</>: The server process is waiting for some activity
+          from an auxilliary process.  <literal>wait_event</> will identify
+          the type of activity waited for.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Timeout</>: The server process is waiting for a timeout
+          to expire.  <literal>wait_event</> will identify the type of timeout
+          waited for.
+         </para>
+        </listitem>
        </itemizedlist>
       </entry>
      </row>
@@ -1085,6 +1123,143 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
          <entry><literal>BufferPin</></entry>
          <entry>Waiting to acquire a pin on a buffer.</entry>
         </row>
+        <row>
+         <entry morerows="11"><literal>Activity</></entry>
+         <entry><literal>ArchiverMain</></entry>
+         <entry>Waiting in main loop of the archiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>AutoVacuumMain</></entry>
+         <entry>Waiting in main loop of autovacuum launcher process.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterHibernate</></entry>
+         <entry>Waiting in background writer process, hibernating.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterMain</></entry>
+         <entry>Waiting in main loop of background writer process background worker.</entry>
+        </row>
+        <row>
+         <entry><literal>CheckpointerMain</></entry>
+         <entry>Waiting in main loop of checkpointer process.</entry>
+        </row>
+        <row>
+         <entry><literal>PgStatMain</></entry>
+         <entry>Waiting in main loop of the statistics collector process.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalAll</></entry>
+         <entry>Waiting for WAL from any kind of source (local, archive or stream) at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalStream</></entry>
+         <entry>Waiting for WAL from a stream at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>SysLoggerMain</></entry>
+         <entry>Waiting in main loop of syslogger process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverMain</></entry>
+         <entry>Waiting in main loop of WAL receiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderMain</></entry>
+         <entry>Waiting in main loop of WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalWriterMain</></entry>
+         <entry>Waiting in main loop of WAL writer process.</entry>
+        </row>
+        <row>
+         <entry morerows="5"><literal>Client</></entry>
+         <entry><literal>SecureRead</></entry>
+         <entry>Waiting to read data from a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SecureWrite</></entry>
+         <entry>Waiting to write data to a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SSLOpenServer</></entry>
+         <entry>Waiting for SSL while attempting connection.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverWaitStart</></entry>
+         <entry>Waiting for startup process to send initial data for streaming replication.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWaitForWAL</></entry>
+         <entry>Waiting for WAL to be flushed in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWriteData</></entry>
+         <entry>Waiting for any activity when processing replies from WAL receiver in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>Extension</></entry>
+         <entry><literal>Extension</></entry>
+         <entry>Waiting in the code path of an extension, should be used by custom plugins and modules</entry>
+        </row>
+        <row>
+         <entry morerows="10"><literal>IPC</></entry>
+         <entry><literal>BgWorkerShutdown</></entry>
+         <entry>Waiting for background worker to shut down.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWorkerStartup</></entry>
+         <entry>Waiting for background worker to start up.</entry>
+        </row>
+        <row>
+         <entry><literal>ExecuteGather</></entry>
+         <entry>Waiting for activity from child process when executing <literal>Gather</> node.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueInternal</></entry>
+         <entry>Waiting for other process to be attached in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueuePutMessage</></entry>
+         <entry>Waiting to put new message in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueReceive</></entry>
+         <entry>Waiting to receive bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueSend</></entry>
+         <entry>Waiting to send bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>ParallelFinish</></entry>
+         <entry>Waiting for parallel workers to finish computing.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSignal</></entry>
+         <entry>Waiting for signal from another backend.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSleep</></entry>
+         <entry>Waiting for a specific lock.</entry>
+        </row>
+        <row>
+         <entry><literal>SyncRep</></entry>
+         <entry>Waiting for WAL commit during synchronous replication.</entry>
+        </row>
+        <row>
+         <entry morerows="2"><literal>Timeout</></entry>
+         <entry><literal>BaseBackupThrottle</></entry>
+         <entry>Waiting during base backup when throttling activity.</entry>
+        </row>
+        <row>
+         <entry><literal>PgSleep</></entry>
+         <entry>Waiting in process that called <function>pg_sleep</>.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryApplyDelay</></entry>
+         <entry>Waiting to apply WAL at recovery because it is delayed.</entry>
+        </row>
       </tbody>
      </tgroup>
     </table>
diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c
index cde0ed3..63d4969 100644
--- a/src/backend/access/transam/parallel.c
+++ b/src/backend/access/transam/parallel.c
@@ -24,6 +24,7 @@
 #include "libpq/pqmq.h"
 #include "miscadmin.h"
 #include "optimizer/planmain.h"
+#include "pgstat.h"
 #include "storage/ipc.h"
 #include "storage/sinval.h"
 #include "storage/spin.h"
@@ -540,7 +541,8 @@ WaitForParallelWorkersToFinish(ParallelContext *pcxt)
 		if (!anyone_alive)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1,
+				  WAIT_IPC, WE_PARALLEL_FINISH);
 		ResetLatch(&MyProc->procLatch);
 	}
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 2189c22..2c51c48 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5827,7 +5827,8 @@ recoveryApplyDelay(XLogReaderState *record)
 
 		WaitLatch(&XLogCtl->recoveryWakeupLatch,
 				  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-				  secs * 1000L + microsecs / 1000);
+				  secs * 1000L + microsecs / 1000,
+				  WAIT_TIMEOUT, WE_RECOVERY_APPLY_DELAY);
 	}
 	return true;
 }
@@ -11376,7 +11377,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 
 						WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								  wait_time);
+							 wait_time, WAIT_ACTIVITY, WE_RECOVERY_WAL_STREAM);
 						ResetLatch(&XLogCtl->recoveryWakeupLatch);
 						now = GetCurrentTimestamp();
 					}
@@ -11539,7 +11540,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					 */
 					WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							  5000L);
+							  5000L, WAIT_ACTIVITY, WE_RECOVERY_WAL_ALL);
 					ResetLatch(&XLogCtl->recoveryWakeupLatch);
 					break;
 				}
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 438d1b2..0178cd1 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -38,6 +38,7 @@
 #include "executor/nodeSubplan.h"
 #include "executor/tqueue.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "utils/memutils.h"
 #include "utils/rel.h"
 
@@ -387,7 +388,7 @@ gather_readnext(GatherState *gatherstate)
 				return NULL;
 
 			/* Nothing to do except wait for developments. */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_IPC, WE_EXECUTE_GATHER);
 			ResetLatch(MyLatch);
 			nvisited = 0;
 		}
diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
index fedb02c..4f78863 100644
--- a/src/backend/libpq/be-secure-openssl.c
+++ b/src/backend/libpq/be-secure-openssl.c
@@ -60,6 +60,7 @@
 
 #include "libpq/libpq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "storage/latch.h"
 #include "tcop/tcopprot.h"
 #include "utils/memutils.h"
@@ -419,7 +420,8 @@ aloop:
 				else
 					waitfor = WL_SOCKET_WRITEABLE;
 
-				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0);
+				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0,
+								  WAIT_CLIENT, WE_SSL_OPEN_SERVER);
 				goto aloop;
 			case SSL_ERROR_SYSCALL:
 				if (r < 0)
diff --git a/src/backend/libpq/be-secure.c b/src/backend/libpq/be-secure.c
index cdd07d5..671bffc 100644
--- a/src/backend/libpq/be-secure.c
+++ b/src/backend/libpq/be-secure.c
@@ -33,6 +33,7 @@
 
 #include "libpq/libpq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "tcop/tcopprot.h"
 #include "utils/memutils.h"
 #include "storage/ipc.h"
@@ -146,7 +147,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 WAIT_CLIENT, WE_SECURE_READ);
 
 		/*
 		 * If the postmaster has died, it's not safe to continue running,
@@ -247,7 +249,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 WAIT_CLIENT, WE_SECURE_WRITE);
 
 		/* See comments in secure_read. */
 		if (event.events & WL_POSTMASTER_DEATH)
diff --git a/src/backend/libpq/pqmq.c b/src/backend/libpq/pqmq.c
index bfe66c6..8c7fff3 100644
--- a/src/backend/libpq/pqmq.c
+++ b/src/backend/libpq/pqmq.c
@@ -17,6 +17,7 @@
 #include "libpq/pqformat.h"
 #include "libpq/pqmq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "tcop/tcopprot.h"
 #include "utils/builtins.h"
 
@@ -171,7 +172,8 @@ mq_putmessage(char msgtype, const char *s, size_t len)
 		if (result != SHM_MQ_WOULD_BLOCK)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0, WAIT_IPC,
+				  WE_MQ_PUT_MESSAGE);
 		ResetLatch(&MyProc->procLatch);
 		CHECK_FOR_INTERRUPTS();
 	}
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 1a92ca1..8558110 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -598,7 +598,8 @@ AutoVacLauncherMain(int argc, char *argv[])
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L));
+					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L),
+					   WAIT_ACTIVITY, WE_AUTOVACUUM_MAIN);
 
 		ResetLatch(MyLatch);
 
diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c
index 699c934..9bdbe68 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -16,6 +16,7 @@
 
 #include "miscadmin.h"
 #include "libpq/pqsignal.h"
+#include "pgstat.h"
 #include "postmaster/bgworker_internals.h"
 #include "postmaster/postmaster.h"
 #include "storage/barrier.h"
@@ -969,7 +970,8 @@ WaitForBackgroundWorkerStartup(BackgroundWorkerHandle *handle, pid_t *pidp)
 			break;
 
 		rc = WaitLatch(MyLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   WAIT_IPC, WE_BGWORKER_STARTUP);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
@@ -1008,7 +1010,8 @@ WaitForBackgroundWorkerShutdown(BackgroundWorkerHandle *handle)
 			break;
 
 		rc = WaitLatch(&MyProc->procLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   WAIT_IPC, WE_BGWORKER_SHUTDOWN);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index 1002034..67ec0ce 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -345,7 +345,9 @@ BackgroundWriterMain(void)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   BgWriterDelay /* ms */ );
+					   BgWriterDelay /* ms */,
+					   WAIT_ACTIVITY,
+					   WE_BGWRITER_MAIN);
 
 		/*
 		 * If no latch event and BgBufferSync says nothing's happening, extend
@@ -372,7 +374,9 @@ BackgroundWriterMain(void)
 			/* Sleep ... */
 			rc = WaitLatch(MyLatch,
 						   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-						   BgWriterDelay * HIBERNATE_FACTOR);
+						   BgWriterDelay * HIBERNATE_FACTOR,
+						   WAIT_ACTIVITY,
+						   WE_BGWRITER_HIBERNATE);
 			/* Reset the notification request in case we timed out */
 			StrategyNotifyBgWriter(-1);
 		}
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index d702a48..a382157 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -556,7 +556,9 @@ CheckpointerMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout * 1000L /* convert to ms */ );
+					   cur_timeout * 1000L /* convert to ms */,
+					   WAIT_ACTIVITY,
+					   WE_CHECKPOINTER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 1aa6466..1fc2794 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -390,7 +390,7 @@ pgarch_MainLoop(void)
 
 				rc = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							   timeout * 1000L);
+							 timeout * 1000L, WAIT_ACTIVITY, WE_ARCHIVER_MAIN);
 				if (rc & WL_TIMEOUT)
 					wakened = true;
 			}
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 8a2ce91..e67abe2 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -3152,6 +3152,18 @@ pgstat_get_wait_event_type(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_type = "BufferPin";
 			break;
+		case WAIT_ACTIVITY:
+			event_type = "Activity";
+			break;
+		case WAIT_CLIENT:
+			event_type = "Client";
+			break;
+		case WAIT_IPC:
+			event_type = "IPC";
+			break;
+		case WAIT_TIMEOUT:
+			event_type = "Timeout";
+			break;
 		default:
 			event_type = "???";
 			break;
@@ -3193,6 +3205,13 @@ pgstat_get_wait_event(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_name = "BufferPin";
 			break;
+		case WAIT_ACTIVITY:
+		case WAIT_CLIENT:
+		case WAIT_EXTENSION:
+		case WAIT_IPC:
+		case WAIT_TIMEOUT:
+			event_name = GetWaitEventIdentifier(eventId);
+			break;
 		default:
 			event_name = "unknown wait event";
 			break;
@@ -3681,8 +3700,7 @@ PgstatCollectorMain(int argc, char *argv[])
 #ifndef WIN32
 		wr = WaitLatchOrSocket(MyLatch,
 					 WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE,
-							   pgStatSock,
-							   -1L);
+					 pgStatSock, -1L, WAIT_ACTIVITY, WE_PGSTAT_MAIN);
 #else
 
 		/*
@@ -3698,7 +3716,9 @@ PgstatCollectorMain(int argc, char *argv[])
 		wr = WaitLatchOrSocket(MyLatch,
 		WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE | WL_TIMEOUT,
 							   pgStatSock,
-							   2 * 1000L /* msec */ );
+							   2 * 1000L /* msec */,
+							   WAIT_ACTIVITY,
+							   WE_PGSTAT_MAIN);
 #endif
 
 		/*
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index e7e488a..c937831 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -35,6 +35,7 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "nodes/pg_list.h"
+#include "pgstat.h"
 #include "pgtime.h"
 #include "postmaster/fork_process.h"
 #include "postmaster/postmaster.h"
@@ -424,7 +425,9 @@ SysLoggerMain(int argc, char *argv[])
 		rc = WaitLatchOrSocket(MyLatch,
 							   WL_LATCH_SET | WL_SOCKET_READABLE | cur_flags,
 							   syslogPipe[0],
-							   cur_timeout);
+							   cur_timeout,
+							   WAIT_ACTIVITY,
+							   WE_SYSLOGGER_MAIN);
 
 		if (rc & WL_SOCKET_READABLE)
 		{
@@ -475,7 +478,9 @@ SysLoggerMain(int argc, char *argv[])
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | cur_flags,
-						 cur_timeout);
+						 cur_timeout,
+						 WAIT_ACTIVITY,
+						 WE_SYSLOGGER_MAIN);
 
 		EnterCriticalSection(&sysloggerSection);
 #endif   /* WIN32 */
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index 11ec56a..e798d83 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -290,7 +290,9 @@ WalWriterMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout);
+					   cur_timeout,
+					   WAIT_ACTIVITY,
+					   WE_WAL_WRITER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index da9b7a6..8e40c34 100644
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -1286,7 +1286,9 @@ throttle(size_t increment)
 		 */
 		wait_result = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								(long) (sleep / 1000));
+								(long) (sleep / 1000),
+								WAIT_TIMEOUT,
+								WE_BASE_BACKUP_THROTTLE);
 
 		if (wait_result & WL_LATCH_SET)
 			CHECK_FOR_INTERRUPTS();
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index b442d06..09c8ce4 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -61,6 +61,7 @@
 
 #include "access/xact.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "replication/syncrep.h"
 #include "replication/walsender.h"
 #include "replication/walsender_private.h"
@@ -258,7 +259,8 @@ SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
 		 * Wait on latch.  Any condition that should wake us up will set the
 		 * latch, so no need for timeout.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1);
+		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1,
+				  WAIT_IPC, WE_SYNC_REP);
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 413ee3a..2660016 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -55,6 +55,7 @@
 #include "libpq/pqformat.h"
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "replication/walreceiver.h"
 #include "replication/walsender.h"
 #include "storage/ipc.h"
@@ -486,7 +487,9 @@ WalReceiverMain(void)
 								   WL_POSTMASTER_DEATH | WL_SOCKET_READABLE |
 									   WL_TIMEOUT | WL_LATCH_SET,
 									   wait_fd,
-									   NAPTIME_PER_CYCLE);
+									   NAPTIME_PER_CYCLE,
+									   WAIT_ACTIVITY,
+									   WE_WAL_RECEIVER_MAIN);
 				if (rc & WL_LATCH_SET)
 				{
 					ResetLatch(&walrcv->latch);
@@ -685,7 +688,8 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 		}
 		SpinLockRelease(&walrcv->mutex);
 
-		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+				  WAIT_CLIENT, WE_WAL_RECEIVER_WAIT_START);
 	}
 
 	if (update_process_title)
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index c7743da..d3f66bb 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -1146,7 +1146,9 @@ WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid,
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  WAIT_CLIENT,
+						  WE_WAL_SENDER_WRITE_DATA);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1272,7 +1274,9 @@ WalSndWaitForWal(XLogRecPtr loc)
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  WAIT_CLIENT,
+						  WE_WAL_SENDER_WAIT_WAL);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1924,7 +1928,9 @@ WalSndLoop(WalSndSendDataCallback send_data)
 
 			/* Sleep until something happens or we time out */
 			WaitLatchOrSocket(MyLatch, wakeEvents,
-							  MyProcPort->sock, sleeptime);
+							  MyProcPort->sock, sleeptime,
+							  WAIT_ACTIVITY,
+							  WE_WAL_SENDER_MAIN);
 		}
 	}
 	return;
diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c
index 9def8a1..8dd9540 100644
--- a/src/backend/storage/ipc/latch.c
+++ b/src/backend/storage/ipc/latch.c
@@ -55,6 +55,7 @@
 #endif
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "portability/instr_time.h"
 #include "postmaster/postmaster.h"
 #include "storage/barrier.h"
@@ -122,6 +123,50 @@ struct WaitEventSet
 #endif
 };
 
+/*
+ * This must match enum WaitEventIdentifier!
+ */
+const char *const WaitEventNames[] = {
+	/* activity */
+	"ArchiverMain",
+	"AutoVacuumMain",
+	"BgWriterHibernate",
+	"BgWriterMain",
+	"CheckpointerMain",
+	"PgStatMain",
+	"RecoveryWalAll",
+	"RecoveryWalStream",
+	"SysLoggerMain",
+	"WalReceiverMain",
+	"WalSenderMain",
+	"WalWriterMain",
+	/* client */
+	"SecureRead",
+	"SecureWrite",
+	"SSLOpenServer",
+	"WalReceiverWaitStart",
+	"WalSenderWaitForWAL",
+	"WalSenderWriteData",
+	/* Extension */
+	"Extension",
+	/* IPC */
+	"BgWorkerShutdown",
+	"BgWorkerStartup",
+	"ExecuteGather",
+	"MessageQueueInternal",
+	"MessageQueuePutMessage",
+	"MessageQueueReceive",
+	"MessageQueueSend",
+	"ParallelFinish",
+	"ProcSignal",
+	"ProcSleep",
+	"SyncRep",
+	/* timeout */
+	"BaseBackupThrottle",
+	"PgSleep",
+	"RecoveryApplyDelay",
+};
+
 #ifndef WIN32
 /* Are we currently in WaitLatch? The signal handler would like to know. */
 static volatile sig_atomic_t waiting = false;
@@ -297,9 +342,11 @@ DisownLatch(volatile Latch *latch)
  * we return all of them in one call, but we will return at least one.
  */
 int
-WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
+WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+		  uint8 classId, uint16 eventId)
 {
-	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout);
+	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout,
+							 classId, eventId);
 }
 
 /*
@@ -316,7 +363,7 @@ WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
  */
 int
 WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
-				  long timeout)
+				  long timeout, uint8 classId, uint16 eventId)
 {
 	int			ret = 0;
 	int			rc;
@@ -344,7 +391,7 @@ WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
 		AddWaitEventToSet(set, ev, sock, NULL, NULL);
 	}
 
-	rc = WaitEventSetWait(set, timeout, &event, 1);
+	rc = WaitEventSetWait(set, timeout, &event, 1, classId, eventId);
 
 	if (rc == 0)
 		ret |= WL_TIMEOUT;
@@ -863,7 +910,8 @@ WaitEventAdjustWin32(WaitEventSet *set, WaitEvent *event)
  */
 int
 WaitEventSetWait(WaitEventSet *set, long timeout,
-				 WaitEvent *occurred_events, int nevents)
+				 WaitEvent *occurred_events, int nevents,
+				 uint8 classId, uint16 eventId)
 {
 	int			returned_events = 0;
 	instr_time	start_time;
@@ -872,6 +920,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 
 	Assert(nevents > 0);
 
+	pgstat_report_wait_start((uint8) classId, (uint16) eventId);
+
 	/*
 	 * Initialize timeout if requested.  We must record the current time so
 	 * that we can determine the remaining timeout if interrupted.
@@ -960,6 +1010,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 	waiting = false;
 #endif
 
+	pgstat_report_wait_end();
+
 	return returned_events;
 }
 
@@ -1491,6 +1543,22 @@ WaitEventSetWaitBlock(WaitEventSet *set, int cur_timeout,
 }
 #endif
 
+
+/*
+ * Return an identifier for a WaitEventSet depending on an event for
+ * statistics collector.
+ */
+const char *
+GetWaitEventIdentifier(uint16 eventId)
+{
+	StaticAssertStmt(lengthof(WaitEventNames) == WE_LAST_TYPE + 1,
+					 "WaitEventNames must match WaitEventIdentifiers");
+	if (eventId > WE_LAST_TYPE)
+		return "???";
+	return WaitEventNames[eventId];
+}
+
+
 /*
  * SetLatch uses SIGUSR1 to wake up the process waiting on the latch.
  *
diff --git a/src/backend/storage/ipc/shm_mq.c b/src/backend/storage/ipc/shm_mq.c
index 5b32782..8d8dc99 100644
--- a/src/backend/storage/ipc/shm_mq.c
+++ b/src/backend/storage/ipc/shm_mq.c
@@ -19,6 +19,7 @@
 #include "postgres.h"
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/bgworker.h"
 #include "storage/procsignal.h"
 #include "storage/shm_mq.h"
@@ -894,7 +895,7 @@ shm_mq_send_bytes(shm_mq_handle *mqh, Size nbytes, const void *data,
 			 * at top of loop, because setting an already-set latch is much
 			 * cheaper than setting one that has been reset.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_IPC, WE_MQ_SEND);
 
 			/* Reset the latch so we don't spin. */
 			ResetLatch(MyLatch);
@@ -991,7 +992,7 @@ shm_mq_receive_bytes(shm_mq *mq, Size bytes_needed, bool nowait,
 		 * loop, because setting an already-set latch is much cheaper than
 		 * setting one that has been reset.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_IPC, WE_MQ_RECEIVE);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
@@ -1090,7 +1091,7 @@ shm_mq_wait_internal(volatile shm_mq *mq, PGPROC *volatile * ptr,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_IPC, WE_MQ_INTERNAL);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 33e7023..ca29f14 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -39,6 +39,7 @@
 #include "access/twophase.h"
 #include "access/xact.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/autovacuum.h"
 #include "replication/slot.h"
 #include "replication/syncrep.h"
@@ -1212,7 +1213,7 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
 		}
 		else
 		{
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_IPC, WE_PROC_SLEEP);
 			ResetLatch(MyLatch);
 			/* check for deadlocks first, as that's probably log-worthy */
 			if (got_deadlock_timeout)
@@ -1724,7 +1725,7 @@ CheckDeadLockAlert(void)
 void
 ProcWaitForSignal(void)
 {
-	WaitLatch(MyLatch, WL_LATCH_SET, 0);
+	WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_IPC, WE_PROC_SIGNAL);
 	ResetLatch(MyLatch);
 	CHECK_FOR_INTERRUPTS();
 }
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 5e705e9..0e2ff93 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -30,6 +30,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "parser/scansup.h"
+#include "pgstat.h"
 #include "postmaster/syslogger.h"
 #include "rewrite/rewriteHandler.h"
 #include "storage/fd.h"
@@ -560,7 +561,9 @@ pg_sleep(PG_FUNCTION_ARGS)
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | WL_TIMEOUT,
-						 delay_ms);
+						 delay_ms,
+						 WAIT_TIMEOUT,
+						 WE_PG_SLEEP);
 		ResetLatch(MyLatch);
 	}
 
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index dc3320d..124cc65 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -721,8 +721,13 @@ typedef enum WaitClass
 	WAIT_LWLOCK_NAMED,
 	WAIT_LWLOCK_TRANCHE,
 	WAIT_LOCK,
-	WAIT_BUFFER_PIN
-}	WaitClass;
+	WAIT_BUFFER_PIN,
+	WAIT_ACTIVITY,
+	WAIT_CLIENT,
+	WAIT_EXTENSION,
+	WAIT_IPC,
+	WAIT_TIMEOUT
+} WaitClass;
 
 
 /* ----------
diff --git a/src/include/storage/latch.h b/src/include/storage/latch.h
index 5179ecc..b0b8436 100644
--- a/src/include/storage/latch.h
+++ b/src/include/storage/latch.h
@@ -135,6 +135,65 @@ typedef struct WaitEvent
 	void	   *user_data;		/* pointer provided in AddWaitEventToSet */
 } WaitEvent;
 
+/*
+ * List of WaitEventSet identifiers used when reporting activity to
+ * statistics collector. Up to 256 different WaitEventIdentifier can be
+ * handled. Those are classified by category first, and then by
+ * alphabetical order. Events are classified into sub-categories following
+ * some basic hierarchy rules:
+ * - "Activity" for main loops of processes waiting for an event.
+ * - "Client" for a socket awaited when a user is connected.
+ * - "IPC", similarly to "Client", for a socket awaited in an auxilliary
+ *   process.
+ * - "Timeout", for a timeout waiting to expire.
+ * - "Extension", to let extension authors a way to use a custom category.
+ */
+typedef enum WaitEventIdentifier
+{
+	/* Activity */
+	WE_ARCHIVER_MAIN,
+	WE_AUTOVACUUM_MAIN,
+	WE_BGWRITER_HIBERNATE,
+	WE_BGWRITER_MAIN,
+	WE_CHECKPOINTER_MAIN,
+	WE_PGSTAT_MAIN,
+	WE_RECOVERY_WAL_ALL,
+	WE_RECOVERY_WAL_STREAM,
+	WE_SYSLOGGER_MAIN,
+	WE_WAL_RECEIVER_MAIN,
+	WE_WAL_SENDER_MAIN,
+	WE_WAL_WRITER_MAIN,
+	/* Client */
+	WE_SECURE_READ,
+	WE_SECURE_WRITE,
+	WE_SSL_OPEN_SERVER,
+	WE_WAL_RECEIVER_WAIT_START,
+	WE_WAL_SENDER_WAIT_WAL,
+	WE_WAL_SENDER_WRITE_DATA,
+	/* Extension */
+	WE_EXTENSION,
+	/* IPC */
+	WE_BGWORKER_SHUTDOWN,
+	WE_BGWORKER_STARTUP,
+	WE_EXECUTE_GATHER,
+	WE_MQ_INTERNAL,
+	WE_MQ_PUT_MESSAGE,
+	WE_MQ_RECEIVE,
+	WE_MQ_SEND,
+	WE_PARALLEL_FINISH,
+	WE_PROC_SIGNAL,
+	WE_PROC_SLEEP,
+	WE_SYNC_REP,
+	/* Timeout */
+	WE_BASE_BACKUP_THROTTLE,
+	WE_PG_SLEEP,
+	WE_RECOVERY_APPLY_DELAY
+} WaitEventIdentifier;
+
+#define WE_LAST_TYPE WE_RECOVERY_APPLY_DELAY
+
+extern const char *const WaitEventName[];
+
 /* forward declaration to avoid exposing latch.c implementation details */
 typedef struct WaitEventSet WaitEventSet;
 
@@ -155,10 +214,15 @@ extern int AddWaitEventToSet(WaitEventSet *set, uint32 events, pgsocket fd,
 				  Latch *latch, void *user_data);
 extern void ModifyWaitEvent(WaitEventSet *set, int pos, uint32 events, Latch *latch);
 
-extern int	WaitEventSetWait(WaitEventSet *set, long timeout, WaitEvent *occurred_events, int nevents);
-extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout);
+extern int	WaitEventSetWait(WaitEventSet *set, long timeout,
+				  WaitEvent *occurred_events, int nevents,
+				  uint8 classId, uint16 eventId);
+extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+				  uint8 classId, uint16 eventId);
 extern int WaitLatchOrSocket(volatile Latch *latch, int wakeEvents,
-				  pgsocket sock, long timeout);
+				  pgsocket sock, long timeout, uint8 classId,
+				  uint16 eventId);
+extern const char *GetWaitEventIdentifier(uint16 eventId);
 
 /*
  * Unix implementation uses SIGUSR1 for inter-process signaling.
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 143df4e..e7f76cd 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -16,6 +16,7 @@
 #include "postgres.h"
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/bgworker.h"
 #include "storage/procsignal.h"
 #include "storage/shm_toc.h"
@@ -279,7 +280,7 @@ wait_for_workers_to_become_ready(worker_state *wstate,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_EXTENSION, WE_EXTENSION);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/test/modules/test_shm_mq/test.c b/src/test/modules/test_shm_mq/test.c
index dd34bc7..15d3874 100644
--- a/src/test/modules/test_shm_mq/test.c
+++ b/src/test/modules/test_shm_mq/test.c
@@ -15,6 +15,7 @@
 
 #include "fmgr.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 
 #include "test_shm_mq.h"
 
@@ -230,7 +231,7 @@ test_shm_mq_pipelined(PG_FUNCTION_ARGS)
 			 * have read or written data and therefore there may now be work
 			 * for us to do.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_EXTENSION, WE_EXTENSION);
 			ResetLatch(MyLatch);
 			CHECK_FOR_INTERRUPTS();
 		}
diff --git a/src/test/modules/worker_spi/worker_spi.c b/src/test/modules/worker_spi/worker_spi.c
index 314e371..697dc42 100644
--- a/src/test/modules/worker_spi/worker_spi.c
+++ b/src/test/modules/worker_spi/worker_spi.c
@@ -227,7 +227,9 @@ worker_spi_main(Datum main_arg)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   worker_spi_naptime * 1000L);
+					   worker_spi_naptime * 1000L,
+					   WAIT_EXTENSION,
+					   WE_EXTENSION);
 		ResetLatch(MyLatch);
 
 		/* emergency bailout if postmaster has died */

diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 8ca1c1c..9222b73 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -17,6 +17,7 @@
 #include "access/xact.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "storage/latch.h"
 #include "utils/hsearch.h"
 #include "utils/memutils.h"
@@ -496,7 +497,9 @@ pgfdw_get_result(PGconn *conn, const char *query)
 			wc = WaitLatchOrSocket(MyLatch,
 								   WL_LATCH_SET | WL_SOCKET_READABLE,
 								   PQsocket(conn),
-								   -1L);
+								   -1L,
+								   WAIT_EXTENSION,
+								   WE_EXTENSION);
 			ResetLatch(MyLatch);
 
 			CHECK_FOR_INTERRUPTS();
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index f400785..bb975c1 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -679,6 +679,42 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
           buffer in question.
          </para>
         </listitem>
+        <listitem>
+         <para>
+          <literal>Activity</>: The server process is idle.  This is used by
+          system processes waiting for activity in their main processing loop.
+          <literal>wait_event</> will identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Extension</>: The server process is waiting for activity
+          in an extension module.  This category is useful for modules to
+          track custom waiting points.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Client</>: The server process is waiting for some activity
+          on a socket from user applications, and that the server expects
+          something to happen that is independent from its internal processes.
+          <literal>wait_event</> will identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>IPC</>: The server process is waiting for some activity
+          from another process in the server.  <literal>wait_event</> will
+          identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Timeout</>: The server process is waiting for a timeout
+          to expire.  <literal>wait_event</> will identify the specific wait
+          point.
+         </para>
+        </listitem>
        </itemizedlist>
       </entry>
      </row>
@@ -1085,6 +1121,143 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
          <entry><literal>BufferPin</></entry>
          <entry>Waiting to acquire a pin on a buffer.</entry>
         </row>
+        <row>
+         <entry morerows="11"><literal>Activity</></entry>
+         <entry><literal>ArchiverMain</></entry>
+         <entry>Waiting in main loop of the archiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>AutoVacuumMain</></entry>
+         <entry>Waiting in main loop of autovacuum launcher process.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterHibernate</></entry>
+         <entry>Waiting in background writer process, hibernating.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterMain</></entry>
+         <entry>Waiting in main loop of background writer process background worker.</entry>
+        </row>
+        <row>
+         <entry><literal>CheckpointerMain</></entry>
+         <entry>Waiting in main loop of checkpointer process.</entry>
+        </row>
+        <row>
+         <entry><literal>PgStatMain</></entry>
+         <entry>Waiting in main loop of the statistics collector process.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalAll</></entry>
+         <entry>Waiting for WAL from any kind of source (local, archive or stream) at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalStream</></entry>
+         <entry>Waiting for WAL from a stream at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>SysLoggerMain</></entry>
+         <entry>Waiting in main loop of syslogger process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverMain</></entry>
+         <entry>Waiting in main loop of WAL receiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderMain</></entry>
+         <entry>Waiting in main loop of WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalWriterMain</></entry>
+         <entry>Waiting in main loop of WAL writer process.</entry>
+        </row>
+        <row>
+         <entry morerows="5"><literal>Client</></entry>
+         <entry><literal>SecureRead</></entry>
+         <entry>Waiting to read data from a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SecureWrite</></entry>
+         <entry>Waiting to write data to a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SSLOpenServer</></entry>
+         <entry>Waiting for SSL while attempting connection.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverWaitStart</></entry>
+         <entry>Waiting for startup process to send initial data for streaming replication.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWaitForWAL</></entry>
+         <entry>Waiting for WAL to be flushed in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWriteData</></entry>
+         <entry>Waiting for any activity when processing replies from WAL receiver in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>Extension</></entry>
+         <entry><literal>Extension</></entry>
+         <entry>Waiting in the code path of an extension, should be used by custom plugins and modules</entry>
+        </row>
+        <row>
+         <entry morerows="10"><literal>IPC</></entry>
+         <entry><literal>BgWorkerShutdown</></entry>
+         <entry>Waiting for background worker to shut down.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWorkerStartup</></entry>
+         <entry>Waiting for background worker to start up.</entry>
+        </row>
+        <row>
+         <entry><literal>ExecuteGather</></entry>
+         <entry>Waiting for activity from child process when executing <literal>Gather</> node.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueInternal</></entry>
+         <entry>Waiting for other process to be attached in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueuePutMessage</></entry>
+         <entry>Waiting to put new message in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueReceive</></entry>
+         <entry>Waiting to receive bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueSend</></entry>
+         <entry>Waiting to send bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>ParallelFinish</></entry>
+         <entry>Waiting for parallel workers to finish computing.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSignal</></entry>
+         <entry>Waiting for signal from another backend.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSleep</></entry>
+         <entry>Waiting for a specific lock.</entry>
+        </row>
+        <row>
+         <entry><literal>SyncRep</></entry>
+         <entry>Waiting for WAL commit during synchronous replication.</entry>
+        </row>
+        <row>
+         <entry morerows="2"><literal>Timeout</></entry>
+         <entry><literal>BaseBackupThrottle</></entry>
+         <entry>Waiting during base backup when throttling activity.</entry>
+        </row>
+        <row>
+         <entry><literal>PgSleep</></entry>
+         <entry>Waiting in process that called <function>pg_sleep</>.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryApplyDelay</></entry>
+         <entry>Waiting to apply WAL at recovery because it is delayed.</entry>
+        </row>
       </tbody>
      </tgroup>
     </table>
diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c
index cde0ed3..63d4969 100644
--- a/src/backend/access/transam/parallel.c
+++ b/src/backend/access/transam/parallel.c
@@ -24,6 +24,7 @@
 #include "libpq/pqmq.h"
 #include "miscadmin.h"
 #include "optimizer/planmain.h"
+#include "pgstat.h"
 #include "storage/ipc.h"
 #include "storage/sinval.h"
 #include "storage/spin.h"
@@ -540,7 +541,8 @@ WaitForParallelWorkersToFinish(ParallelContext *pcxt)
 		if (!anyone_alive)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1,
+				  WAIT_IPC, WE_PARALLEL_FINISH);
 		ResetLatch(&MyProc->procLatch);
 	}
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index c1b9a97..e65fd0a 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5827,7 +5827,8 @@ recoveryApplyDelay(XLogReaderState *record)
 
 		WaitLatch(&XLogCtl->recoveryWakeupLatch,
 				  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-				  secs * 1000L + microsecs / 1000);
+				  secs * 1000L + microsecs / 1000,
+				  WAIT_TIMEOUT, WE_RECOVERY_APPLY_DELAY);
 	}
 	return true;
 }
@@ -11387,7 +11388,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 
 						WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								  wait_time);
+							 wait_time, WAIT_ACTIVITY, WE_RECOVERY_WAL_STREAM);
 						ResetLatch(&XLogCtl->recoveryWakeupLatch);
 						now = GetCurrentTimestamp();
 					}
@@ -11550,7 +11551,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					 */
 					WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							  5000L);
+							  5000L, WAIT_ACTIVITY, WE_RECOVERY_WAL_ALL);
 					ResetLatch(&XLogCtl->recoveryWakeupLatch);
 					break;
 				}
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 438d1b2..0178cd1 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -38,6 +38,7 @@
 #include "executor/nodeSubplan.h"
 #include "executor/tqueue.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "utils/memutils.h"
 #include "utils/rel.h"
 
@@ -387,7 +388,7 @@ gather_readnext(GatherState *gatherstate)
 				return NULL;
 
 			/* Nothing to do except wait for developments. */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_IPC, WE_EXECUTE_GATHER);
 			ResetLatch(MyLatch);
 			nvisited = 0;
 		}
diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
index fedb02c..4f78863 100644
--- a/src/backend/libpq/be-secure-openssl.c
+++ b/src/backend/libpq/be-secure-openssl.c
@@ -60,6 +60,7 @@
 
 #include "libpq/libpq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "storage/latch.h"
 #include "tcop/tcopprot.h"
 #include "utils/memutils.h"
@@ -419,7 +420,8 @@ aloop:
 				else
 					waitfor = WL_SOCKET_WRITEABLE;
 
-				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0);
+				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0,
+								  WAIT_CLIENT, WE_SSL_OPEN_SERVER);
 				goto aloop;
 			case SSL_ERROR_SYSCALL:
 				if (r < 0)
diff --git a/src/backend/libpq/be-secure.c b/src/backend/libpq/be-secure.c
index cdd07d5..671bffc 100644
--- a/src/backend/libpq/be-secure.c
+++ b/src/backend/libpq/be-secure.c
@@ -33,6 +33,7 @@
 
 #include "libpq/libpq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "tcop/tcopprot.h"
 #include "utils/memutils.h"
 #include "storage/ipc.h"
@@ -146,7 +147,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 WAIT_CLIENT, WE_SECURE_READ);
 
 		/*
 		 * If the postmaster has died, it's not safe to continue running,
@@ -247,7 +249,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 WAIT_CLIENT, WE_SECURE_WRITE);
 
 		/* See comments in secure_read. */
 		if (event.events & WL_POSTMASTER_DEATH)
diff --git a/src/backend/libpq/pqmq.c b/src/backend/libpq/pqmq.c
index bfe66c6..8c7fff3 100644
--- a/src/backend/libpq/pqmq.c
+++ b/src/backend/libpq/pqmq.c
@@ -17,6 +17,7 @@
 #include "libpq/pqformat.h"
 #include "libpq/pqmq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "tcop/tcopprot.h"
 #include "utils/builtins.h"
 
@@ -171,7 +172,8 @@ mq_putmessage(char msgtype, const char *s, size_t len)
 		if (result != SHM_MQ_WOULD_BLOCK)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0, WAIT_IPC,
+				  WE_MQ_PUT_MESSAGE);
 		ResetLatch(&MyProc->procLatch);
 		CHECK_FOR_INTERRUPTS();
 	}
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 1a92ca1..8558110 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -598,7 +598,8 @@ AutoVacLauncherMain(int argc, char *argv[])
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L));
+					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L),
+					   WAIT_ACTIVITY, WE_AUTOVACUUM_MAIN);
 
 		ResetLatch(MyLatch);
 
diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c
index 699c934..9bdbe68 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -16,6 +16,7 @@
 
 #include "miscadmin.h"
 #include "libpq/pqsignal.h"
+#include "pgstat.h"
 #include "postmaster/bgworker_internals.h"
 #include "postmaster/postmaster.h"
 #include "storage/barrier.h"
@@ -969,7 +970,8 @@ WaitForBackgroundWorkerStartup(BackgroundWorkerHandle *handle, pid_t *pidp)
 			break;
 
 		rc = WaitLatch(MyLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   WAIT_IPC, WE_BGWORKER_STARTUP);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
@@ -1008,7 +1010,8 @@ WaitForBackgroundWorkerShutdown(BackgroundWorkerHandle *handle)
 			break;
 
 		rc = WaitLatch(&MyProc->procLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   WAIT_IPC, WE_BGWORKER_SHUTDOWN);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index 1002034..67ec0ce 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -345,7 +345,9 @@ BackgroundWriterMain(void)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   BgWriterDelay /* ms */ );
+					   BgWriterDelay /* ms */,
+					   WAIT_ACTIVITY,
+					   WE_BGWRITER_MAIN);
 
 		/*
 		 * If no latch event and BgBufferSync says nothing's happening, extend
@@ -372,7 +374,9 @@ BackgroundWriterMain(void)
 			/* Sleep ... */
 			rc = WaitLatch(MyLatch,
 						   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-						   BgWriterDelay * HIBERNATE_FACTOR);
+						   BgWriterDelay * HIBERNATE_FACTOR,
+						   WAIT_ACTIVITY,
+						   WE_BGWRITER_HIBERNATE);
 			/* Reset the notification request in case we timed out */
 			StrategyNotifyBgWriter(-1);
 		}
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index d702a48..a382157 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -556,7 +556,9 @@ CheckpointerMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout * 1000L /* convert to ms */ );
+					   cur_timeout * 1000L /* convert to ms */,
+					   WAIT_ACTIVITY,
+					   WE_CHECKPOINTER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 1aa6466..1fc2794 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -390,7 +390,7 @@ pgarch_MainLoop(void)
 
 				rc = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							   timeout * 1000L);
+							 timeout * 1000L, WAIT_ACTIVITY, WE_ARCHIVER_MAIN);
 				if (rc & WL_TIMEOUT)
 					wakened = true;
 			}
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 96578dc..019086a 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -3155,6 +3155,18 @@ pgstat_get_wait_event_type(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_type = "BufferPin";
 			break;
+		case WAIT_ACTIVITY:
+			event_type = "Activity";
+			break;
+		case WAIT_CLIENT:
+			event_type = "Client";
+			break;
+		case WAIT_IPC:
+			event_type = "IPC";
+			break;
+		case WAIT_TIMEOUT:
+			event_type = "Timeout";
+			break;
 		default:
 			event_type = "???";
 			break;
@@ -3196,6 +3208,13 @@ pgstat_get_wait_event(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_name = "BufferPin";
 			break;
+		case WAIT_ACTIVITY:
+		case WAIT_CLIENT:
+		case WAIT_EXTENSION:
+		case WAIT_IPC:
+		case WAIT_TIMEOUT:
+			event_name = GetWaitEventIdentifier(eventId);
+			break;
 		default:
 			event_name = "unknown wait event";
 			break;
@@ -3684,8 +3703,7 @@ PgstatCollectorMain(int argc, char *argv[])
 #ifndef WIN32
 		wr = WaitLatchOrSocket(MyLatch,
 					 WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE,
-							   pgStatSock,
-							   -1L);
+					 pgStatSock, -1L, WAIT_ACTIVITY, WE_PGSTAT_MAIN);
 #else
 
 		/*
@@ -3701,7 +3719,9 @@ PgstatCollectorMain(int argc, char *argv[])
 		wr = WaitLatchOrSocket(MyLatch,
 		WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE | WL_TIMEOUT,
 							   pgStatSock,
-							   2 * 1000L /* msec */ );
+							   2 * 1000L /* msec */,
+							   WAIT_ACTIVITY,
+							   WE_PGSTAT_MAIN);
 #endif
 
 		/*
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index e7e488a..c937831 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -35,6 +35,7 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "nodes/pg_list.h"
+#include "pgstat.h"
 #include "pgtime.h"
 #include "postmaster/fork_process.h"
 #include "postmaster/postmaster.h"
@@ -424,7 +425,9 @@ SysLoggerMain(int argc, char *argv[])
 		rc = WaitLatchOrSocket(MyLatch,
 							   WL_LATCH_SET | WL_SOCKET_READABLE | cur_flags,
 							   syslogPipe[0],
-							   cur_timeout);
+							   cur_timeout,
+							   WAIT_ACTIVITY,
+							   WE_SYSLOGGER_MAIN);
 
 		if (rc & WL_SOCKET_READABLE)
 		{
@@ -475,7 +478,9 @@ SysLoggerMain(int argc, char *argv[])
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | cur_flags,
-						 cur_timeout);
+						 cur_timeout,
+						 WAIT_ACTIVITY,
+						 WE_SYSLOGGER_MAIN);
 
 		EnterCriticalSection(&sysloggerSection);
 #endif   /* WIN32 */
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index 11ec56a..e798d83 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -290,7 +290,9 @@ WalWriterMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout);
+					   cur_timeout,
+					   WAIT_ACTIVITY,
+					   WE_WAL_WRITER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index da9b7a6..8e40c34 100644
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -1286,7 +1286,9 @@ throttle(size_t increment)
 		 */
 		wait_result = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								(long) (sleep / 1000));
+								(long) (sleep / 1000),
+								WAIT_TIMEOUT,
+								WE_BASE_BACKUP_THROTTLE);
 
 		if (wait_result & WL_LATCH_SET)
 			CHECK_FOR_INTERRUPTS();
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index b442d06..09c8ce4 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -61,6 +61,7 @@
 
 #include "access/xact.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "replication/syncrep.h"
 #include "replication/walsender.h"
 #include "replication/walsender_private.h"
@@ -258,7 +259,8 @@ SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
 		 * Wait on latch.  Any condition that should wake us up will set the
 		 * latch, so no need for timeout.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1);
+		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1,
+				  WAIT_IPC, WE_SYNC_REP);
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 413ee3a..2660016 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -55,6 +55,7 @@
 #include "libpq/pqformat.h"
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "replication/walreceiver.h"
 #include "replication/walsender.h"
 #include "storage/ipc.h"
@@ -486,7 +487,9 @@ WalReceiverMain(void)
 								   WL_POSTMASTER_DEATH | WL_SOCKET_READABLE |
 									   WL_TIMEOUT | WL_LATCH_SET,
 									   wait_fd,
-									   NAPTIME_PER_CYCLE);
+									   NAPTIME_PER_CYCLE,
+									   WAIT_ACTIVITY,
+									   WE_WAL_RECEIVER_MAIN);
 				if (rc & WL_LATCH_SET)
 				{
 					ResetLatch(&walrcv->latch);
@@ -685,7 +688,8 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 		}
 		SpinLockRelease(&walrcv->mutex);
 
-		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+				  WAIT_CLIENT, WE_WAL_RECEIVER_WAIT_START);
 	}
 
 	if (update_process_title)
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index c7743da..d3f66bb 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -1146,7 +1146,9 @@ WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid,
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  WAIT_CLIENT,
+						  WE_WAL_SENDER_WRITE_DATA);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1272,7 +1274,9 @@ WalSndWaitForWal(XLogRecPtr loc)
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  WAIT_CLIENT,
+						  WE_WAL_SENDER_WAIT_WAL);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1924,7 +1928,9 @@ WalSndLoop(WalSndSendDataCallback send_data)
 
 			/* Sleep until something happens or we time out */
 			WaitLatchOrSocket(MyLatch, wakeEvents,
-							  MyProcPort->sock, sleeptime);
+							  MyProcPort->sock, sleeptime,
+							  WAIT_ACTIVITY,
+							  WE_WAL_SENDER_MAIN);
 		}
 	}
 	return;
diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c
index 9def8a1..8dcf569 100644
--- a/src/backend/storage/ipc/latch.c
+++ b/src/backend/storage/ipc/latch.c
@@ -55,6 +55,7 @@
 #endif
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "portability/instr_time.h"
 #include "postmaster/postmaster.h"
 #include "storage/barrier.h"
@@ -122,6 +123,50 @@ struct WaitEventSet
 #endif
 };
 
+/*
+ * This must match enum WaitEventIdentifier!
+ */
+const char *const WaitEventNames[] = {
+	/* Activity */
+	"ArchiverMain",
+	"AutoVacuumMain",
+	"BgWriterHibernate",
+	"BgWriterMain",
+	"CheckpointerMain",
+	"PgStatMain",
+	"RecoveryWalAll",
+	"RecoveryWalStream",
+	"SysLoggerMain",
+	"WalReceiverMain",
+	"WalSenderMain",
+	"WalWriterMain",
+	/* Client */
+	"SecureRead",
+	"SecureWrite",
+	"SSLOpenServer",
+	"WalReceiverWaitStart",
+	"WalSenderWaitForWAL",
+	"WalSenderWriteData",
+	/* Extension */
+	"Extension",
+	/* IPC */
+	"BgWorkerShutdown",
+	"BgWorkerStartup",
+	"ExecuteGather",
+	"MessageQueueInternal",
+	"MessageQueuePutMessage",
+	"MessageQueueReceive",
+	"MessageQueueSend",
+	"ParallelFinish",
+	"ProcSignal",
+	"ProcSleep",
+	"SyncRep",
+	/* Timeout */
+	"BaseBackupThrottle",
+	"PgSleep",
+	"RecoveryApplyDelay",
+};
+
 #ifndef WIN32
 /* Are we currently in WaitLatch? The signal handler would like to know. */
 static volatile sig_atomic_t waiting = false;
@@ -297,9 +342,11 @@ DisownLatch(volatile Latch *latch)
  * we return all of them in one call, but we will return at least one.
  */
 int
-WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
+WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+		  uint8 classId, uint16 eventId)
 {
-	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout);
+	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout,
+							 classId, eventId);
 }
 
 /*
@@ -316,7 +363,7 @@ WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
  */
 int
 WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
-				  long timeout)
+				  long timeout, uint8 classId, uint16 eventId)
 {
 	int			ret = 0;
 	int			rc;
@@ -344,7 +391,7 @@ WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
 		AddWaitEventToSet(set, ev, sock, NULL, NULL);
 	}
 
-	rc = WaitEventSetWait(set, timeout, &event, 1);
+	rc = WaitEventSetWait(set, timeout, &event, 1, classId, eventId);
 
 	if (rc == 0)
 		ret |= WL_TIMEOUT;
@@ -863,7 +910,8 @@ WaitEventAdjustWin32(WaitEventSet *set, WaitEvent *event)
  */
 int
 WaitEventSetWait(WaitEventSet *set, long timeout,
-				 WaitEvent *occurred_events, int nevents)
+				 WaitEvent *occurred_events, int nevents,
+				 uint8 classId, uint16 eventId)
 {
 	int			returned_events = 0;
 	instr_time	start_time;
@@ -872,6 +920,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 
 	Assert(nevents > 0);
 
+	pgstat_report_wait_start((uint8) classId, (uint16) eventId);
+
 	/*
 	 * Initialize timeout if requested.  We must record the current time so
 	 * that we can determine the remaining timeout if interrupted.
@@ -960,6 +1010,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 	waiting = false;
 #endif
 
+	pgstat_report_wait_end();
+
 	return returned_events;
 }
 
@@ -1491,6 +1543,22 @@ WaitEventSetWaitBlock(WaitEventSet *set, int cur_timeout,
 }
 #endif
 
+
+/*
+ * Return an identifier for a WaitEventSet depending on an event for
+ * statistics collector.
+ */
+const char *
+GetWaitEventIdentifier(uint16 eventId)
+{
+	StaticAssertStmt(lengthof(WaitEventNames) == WE_LAST_TYPE + 1,
+					 "WaitEventNames must match WaitEventIdentifiers");
+	if (eventId > WE_LAST_TYPE)
+		return "???";
+	return WaitEventNames[eventId];
+}
+
+
 /*
  * SetLatch uses SIGUSR1 to wake up the process waiting on the latch.
  *
diff --git a/src/backend/storage/ipc/shm_mq.c b/src/backend/storage/ipc/shm_mq.c
index 5b32782..8d8dc99 100644
--- a/src/backend/storage/ipc/shm_mq.c
+++ b/src/backend/storage/ipc/shm_mq.c
@@ -19,6 +19,7 @@
 #include "postgres.h"
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/bgworker.h"
 #include "storage/procsignal.h"
 #include "storage/shm_mq.h"
@@ -894,7 +895,7 @@ shm_mq_send_bytes(shm_mq_handle *mqh, Size nbytes, const void *data,
 			 * at top of loop, because setting an already-set latch is much
 			 * cheaper than setting one that has been reset.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_IPC, WE_MQ_SEND);
 
 			/* Reset the latch so we don't spin. */
 			ResetLatch(MyLatch);
@@ -991,7 +992,7 @@ shm_mq_receive_bytes(shm_mq *mq, Size bytes_needed, bool nowait,
 		 * loop, because setting an already-set latch is much cheaper than
 		 * setting one that has been reset.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_IPC, WE_MQ_RECEIVE);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
@@ -1090,7 +1091,7 @@ shm_mq_wait_internal(volatile shm_mq *mq, PGPROC *volatile * ptr,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_IPC, WE_MQ_INTERNAL);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 33e7023..ca29f14 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -39,6 +39,7 @@
 #include "access/twophase.h"
 #include "access/xact.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/autovacuum.h"
 #include "replication/slot.h"
 #include "replication/syncrep.h"
@@ -1212,7 +1213,7 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
 		}
 		else
 		{
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_IPC, WE_PROC_SLEEP);
 			ResetLatch(MyLatch);
 			/* check for deadlocks first, as that's probably log-worthy */
 			if (got_deadlock_timeout)
@@ -1724,7 +1725,7 @@ CheckDeadLockAlert(void)
 void
 ProcWaitForSignal(void)
 {
-	WaitLatch(MyLatch, WL_LATCH_SET, 0);
+	WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_IPC, WE_PROC_SIGNAL);
 	ResetLatch(MyLatch);
 	CHECK_FOR_INTERRUPTS();
 }
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 5e705e9..0e2ff93 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -30,6 +30,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "parser/scansup.h"
+#include "pgstat.h"
 #include "postmaster/syslogger.h"
 #include "rewrite/rewriteHandler.h"
 #include "storage/fd.h"
@@ -560,7 +561,9 @@ pg_sleep(PG_FUNCTION_ARGS)
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | WL_TIMEOUT,
-						 delay_ms);
+						 delay_ms,
+						 WAIT_TIMEOUT,
+						 WE_PG_SLEEP);
 		ResetLatch(MyLatch);
 	}
 
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0c98c59..b3f707e 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -721,8 +721,13 @@ typedef enum WaitClass
 	WAIT_LWLOCK_NAMED,
 	WAIT_LWLOCK_TRANCHE,
 	WAIT_LOCK,
-	WAIT_BUFFER_PIN
-}	WaitClass;
+	WAIT_BUFFER_PIN,
+	WAIT_ACTIVITY,
+	WAIT_CLIENT,
+	WAIT_EXTENSION,
+	WAIT_IPC,
+	WAIT_TIMEOUT
+} WaitClass;
 
 
 /* ----------
diff --git a/src/include/storage/latch.h b/src/include/storage/latch.h
index 5179ecc..8261830 100644
--- a/src/include/storage/latch.h
+++ b/src/include/storage/latch.h
@@ -135,6 +135,66 @@ typedef struct WaitEvent
 	void	   *user_data;		/* pointer provided in AddWaitEventToSet */
 } WaitEvent;
 
+/*
+ * List of WaitEventSet identifiers used when reporting activity to
+ * statistics collector. Up to 256 different WaitEventIdentifier can be
+ * handled. Those are classified by category first, and then by
+ * alphabetical order. Events are classified into sub-categories following
+ * some basic hierarchy rules:
+ * - "Activity" for main loops of processes waiting for an event.
+ * - "Client" for a socket awaited when a user is connected.
+ * - "IPC", similarly to "Client", for a socket awaited from another
+ *   server process.
+ * - "Timeout", for a timeout waiting to expire.
+ * - "Extension", to let extension modules a way to define a custom wait
+ *   point.
+ */
+typedef enum WaitEventIdentifier
+{
+	/* Activity */
+	WE_ARCHIVER_MAIN,
+	WE_AUTOVACUUM_MAIN,
+	WE_BGWRITER_HIBERNATE,
+	WE_BGWRITER_MAIN,
+	WE_CHECKPOINTER_MAIN,
+	WE_PGSTAT_MAIN,
+	WE_RECOVERY_WAL_ALL,
+	WE_RECOVERY_WAL_STREAM,
+	WE_SYSLOGGER_MAIN,
+	WE_WAL_RECEIVER_MAIN,
+	WE_WAL_SENDER_MAIN,
+	WE_WAL_WRITER_MAIN,
+	/* Client */
+	WE_SECURE_READ,
+	WE_SECURE_WRITE,
+	WE_SSL_OPEN_SERVER,
+	WE_WAL_RECEIVER_WAIT_START,
+	WE_WAL_SENDER_WAIT_WAL,
+	WE_WAL_SENDER_WRITE_DATA,
+	/* Extension */
+	WE_EXTENSION,
+	/* IPC */
+	WE_BGWORKER_SHUTDOWN,
+	WE_BGWORKER_STARTUP,
+	WE_EXECUTE_GATHER,
+	WE_MQ_INTERNAL,
+	WE_MQ_PUT_MESSAGE,
+	WE_MQ_RECEIVE,
+	WE_MQ_SEND,
+	WE_PARALLEL_FINISH,
+	WE_PROC_SIGNAL,
+	WE_PROC_SLEEP,
+	WE_SYNC_REP,
+	/* Timeout */
+	WE_BASE_BACKUP_THROTTLE,
+	WE_PG_SLEEP,
+	WE_RECOVERY_APPLY_DELAY
+} WaitEventIdentifier;
+
+#define WE_LAST_TYPE WE_RECOVERY_APPLY_DELAY
+
+extern const char *const WaitEventName[];
+
 /* forward declaration to avoid exposing latch.c implementation details */
 typedef struct WaitEventSet WaitEventSet;
 
@@ -155,10 +215,15 @@ extern int AddWaitEventToSet(WaitEventSet *set, uint32 events, pgsocket fd,
 				  Latch *latch, void *user_data);
 extern void ModifyWaitEvent(WaitEventSet *set, int pos, uint32 events, Latch *latch);
 
-extern int	WaitEventSetWait(WaitEventSet *set, long timeout, WaitEvent *occurred_events, int nevents);
-extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout);
+extern int	WaitEventSetWait(WaitEventSet *set, long timeout,
+				  WaitEvent *occurred_events, int nevents,
+				  uint8 classId, uint16 eventId);
+extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+				  uint8 classId, uint16 eventId);
 extern int WaitLatchOrSocket(volatile Latch *latch, int wakeEvents,
-				  pgsocket sock, long timeout);
+				  pgsocket sock, long timeout, uint8 classId,
+				  uint16 eventId);
+extern const char *GetWaitEventIdentifier(uint16 eventId);
 
 /*
  * Unix implementation uses SIGUSR1 for inter-process signaling.
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 143df4e..e7f76cd 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -16,6 +16,7 @@
 #include "postgres.h"
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/bgworker.h"
 #include "storage/procsignal.h"
 #include "storage/shm_toc.h"
@@ -279,7 +280,7 @@ wait_for_workers_to_become_ready(worker_state *wstate,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_EXTENSION, WE_EXTENSION);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/test/modules/test_shm_mq/test.c b/src/test/modules/test_shm_mq/test.c
index dd34bc7..15d3874 100644
--- a/src/test/modules/test_shm_mq/test.c
+++ b/src/test/modules/test_shm_mq/test.c
@@ -15,6 +15,7 @@
 
 #include "fmgr.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 
 #include "test_shm_mq.h"
 
@@ -230,7 +231,7 @@ test_shm_mq_pipelined(PG_FUNCTION_ARGS)
 			 * have read or written data and therefore there may now be work
 			 * for us to do.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_EXTENSION, WE_EXTENSION);
 			ResetLatch(MyLatch);
 			CHECK_FOR_INTERRUPTS();
 		}
diff --git a/src/test/modules/worker_spi/worker_spi.c b/src/test/modules/worker_spi/worker_spi.c
index 314e371..697dc42 100644
--- a/src/test/modules/worker_spi/worker_spi.c
+++ b/src/test/modules/worker_spi/worker_spi.c
@@ -227,7 +227,9 @@ worker_spi_main(Datum main_arg)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   worker_spi_naptime * 1000L);
+					   worker_spi_naptime * 1000L,
+					   WAIT_EXTENSION,
+					   WE_EXTENSION);
 		ResetLatch(MyLatch);
 
 		/* emergency bailout if postmaster has died */

diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 8ca1c1c..9222b73 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -17,6 +17,7 @@
 #include "access/xact.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "storage/latch.h"
 #include "utils/hsearch.h"
 #include "utils/memutils.h"
@@ -496,7 +497,9 @@ pgfdw_get_result(PGconn *conn, const char *query)
 			wc = WaitLatchOrSocket(MyLatch,
 								   WL_LATCH_SET | WL_SOCKET_READABLE,
 								   PQsocket(conn),
-								   -1L);
+								   -1L,
+								   WAIT_EXTENSION,
+								   WE_EXTENSION);
 			ResetLatch(MyLatch);
 
 			CHECK_FOR_INTERRUPTS();
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index f400785..bb975c1 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -679,6 +679,42 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
           buffer in question.
          </para>
         </listitem>
+        <listitem>
+         <para>
+          <literal>Activity</>: The server process is idle.  This is used by
+          system processes waiting for activity in their main processing loop.
+          <literal>wait_event</> will identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Extension</>: The server process is waiting for activity
+          in an extension module.  This category is useful for modules to
+          track custom waiting points.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Client</>: The server process is waiting for some activity
+          on a socket from user applications, and that the server expects
+          something to happen that is independent from its internal processes.
+          <literal>wait_event</> will identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>IPC</>: The server process is waiting for some activity
+          from another process in the server.  <literal>wait_event</> will
+          identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Timeout</>: The server process is waiting for a timeout
+          to expire.  <literal>wait_event</> will identify the specific wait
+          point.
+         </para>
+        </listitem>
        </itemizedlist>
       </entry>
      </row>
@@ -1085,6 +1121,143 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
          <entry><literal>BufferPin</></entry>
          <entry>Waiting to acquire a pin on a buffer.</entry>
         </row>
+        <row>
+         <entry morerows="11"><literal>Activity</></entry>
+         <entry><literal>ArchiverMain</></entry>
+         <entry>Waiting in main loop of the archiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>AutoVacuumMain</></entry>
+         <entry>Waiting in main loop of autovacuum launcher process.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterHibernate</></entry>
+         <entry>Waiting in background writer process, hibernating.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterMain</></entry>
+         <entry>Waiting in main loop of background writer process background worker.</entry>
+        </row>
+        <row>
+         <entry><literal>CheckpointerMain</></entry>
+         <entry>Waiting in main loop of checkpointer process.</entry>
+        </row>
+        <row>
+         <entry><literal>PgStatMain</></entry>
+         <entry>Waiting in main loop of the statistics collector process.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalAll</></entry>
+         <entry>Waiting for WAL from any kind of source (local, archive or stream) at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalStream</></entry>
+         <entry>Waiting for WAL from a stream at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>SysLoggerMain</></entry>
+         <entry>Waiting in main loop of syslogger process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverMain</></entry>
+         <entry>Waiting in main loop of WAL receiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderMain</></entry>
+         <entry>Waiting in main loop of WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalWriterMain</></entry>
+         <entry>Waiting in main loop of WAL writer process.</entry>
+        </row>
+        <row>
+         <entry morerows="5"><literal>Client</></entry>
+         <entry><literal>SecureRead</></entry>
+         <entry>Waiting to read data from a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SecureWrite</></entry>
+         <entry>Waiting to write data to a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SSLOpenServer</></entry>
+         <entry>Waiting for SSL while attempting connection.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverWaitStart</></entry>
+         <entry>Waiting for startup process to send initial data for streaming replication.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWaitForWAL</></entry>
+         <entry>Waiting for WAL to be flushed in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWriteData</></entry>
+         <entry>Waiting for any activity when processing replies from WAL receiver in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>Extension</></entry>
+         <entry><literal>Extension</></entry>
+         <entry>Waiting in the code path of an extension, should be used by custom plugins and modules</entry>
+        </row>
+        <row>
+         <entry morerows="10"><literal>IPC</></entry>
+         <entry><literal>BgWorkerShutdown</></entry>
+         <entry>Waiting for background worker to shut down.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWorkerStartup</></entry>
+         <entry>Waiting for background worker to start up.</entry>
+        </row>
+        <row>
+         <entry><literal>ExecuteGather</></entry>
+         <entry>Waiting for activity from child process when executing <literal>Gather</> node.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueInternal</></entry>
+         <entry>Waiting for other process to be attached in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueuePutMessage</></entry>
+         <entry>Waiting to put new message in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueReceive</></entry>
+         <entry>Waiting to receive bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueSend</></entry>
+         <entry>Waiting to send bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>ParallelFinish</></entry>
+         <entry>Waiting for parallel workers to finish computing.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSignal</></entry>
+         <entry>Waiting for signal from another backend.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSleep</></entry>
+         <entry>Waiting for a specific lock.</entry>
+        </row>
+        <row>
+         <entry><literal>SyncRep</></entry>
+         <entry>Waiting for WAL commit during synchronous replication.</entry>
+        </row>
+        <row>
+         <entry morerows="2"><literal>Timeout</></entry>
+         <entry><literal>BaseBackupThrottle</></entry>
+         <entry>Waiting during base backup when throttling activity.</entry>
+        </row>
+        <row>
+         <entry><literal>PgSleep</></entry>
+         <entry>Waiting in process that called <function>pg_sleep</>.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryApplyDelay</></entry>
+         <entry>Waiting to apply WAL at recovery because it is delayed.</entry>
+        </row>
       </tbody>
      </tgroup>
     </table>
diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c
index cde0ed3..63d4969 100644
--- a/src/backend/access/transam/parallel.c
+++ b/src/backend/access/transam/parallel.c
@@ -24,6 +24,7 @@
 #include "libpq/pqmq.h"
 #include "miscadmin.h"
 #include "optimizer/planmain.h"
+#include "pgstat.h"
 #include "storage/ipc.h"
 #include "storage/sinval.h"
 #include "storage/spin.h"
@@ -540,7 +541,8 @@ WaitForParallelWorkersToFinish(ParallelContext *pcxt)
 		if (!anyone_alive)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1,
+				  WAIT_IPC, WE_PARALLEL_FINISH);
 		ResetLatch(&MyProc->procLatch);
 	}
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index c1b9a97..e65fd0a 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5827,7 +5827,8 @@ recoveryApplyDelay(XLogReaderState *record)
 
 		WaitLatch(&XLogCtl->recoveryWakeupLatch,
 				  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-				  secs * 1000L + microsecs / 1000);
+				  secs * 1000L + microsecs / 1000,
+				  WAIT_TIMEOUT, WE_RECOVERY_APPLY_DELAY);
 	}
 	return true;
 }
@@ -11387,7 +11388,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 
 						WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								  wait_time);
+							 wait_time, WAIT_ACTIVITY, WE_RECOVERY_WAL_STREAM);
 						ResetLatch(&XLogCtl->recoveryWakeupLatch);
 						now = GetCurrentTimestamp();
 					}
@@ -11550,7 +11551,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					 */
 					WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							  5000L);
+							  5000L, WAIT_ACTIVITY, WE_RECOVERY_WAL_ALL);
 					ResetLatch(&XLogCtl->recoveryWakeupLatch);
 					break;
 				}
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 438d1b2..0178cd1 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -38,6 +38,7 @@
 #include "executor/nodeSubplan.h"
 #include "executor/tqueue.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "utils/memutils.h"
 #include "utils/rel.h"
 
@@ -387,7 +388,7 @@ gather_readnext(GatherState *gatherstate)
 				return NULL;
 
 			/* Nothing to do except wait for developments. */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_IPC, WE_EXECUTE_GATHER);
 			ResetLatch(MyLatch);
 			nvisited = 0;
 		}
diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
index fedb02c..4f78863 100644
--- a/src/backend/libpq/be-secure-openssl.c
+++ b/src/backend/libpq/be-secure-openssl.c
@@ -60,6 +60,7 @@
 
 #include "libpq/libpq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "storage/latch.h"
 #include "tcop/tcopprot.h"
 #include "utils/memutils.h"
@@ -419,7 +420,8 @@ aloop:
 				else
 					waitfor = WL_SOCKET_WRITEABLE;
 
-				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0);
+				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0,
+								  WAIT_CLIENT, WE_SSL_OPEN_SERVER);
 				goto aloop;
 			case SSL_ERROR_SYSCALL:
 				if (r < 0)
diff --git a/src/backend/libpq/be-secure.c b/src/backend/libpq/be-secure.c
index cdd07d5..671bffc 100644
--- a/src/backend/libpq/be-secure.c
+++ b/src/backend/libpq/be-secure.c
@@ -33,6 +33,7 @@
 
 #include "libpq/libpq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "tcop/tcopprot.h"
 #include "utils/memutils.h"
 #include "storage/ipc.h"
@@ -146,7 +147,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 WAIT_CLIENT, WE_SECURE_READ);
 
 		/*
 		 * If the postmaster has died, it's not safe to continue running,
@@ -247,7 +249,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 WAIT_CLIENT, WE_SECURE_WRITE);
 
 		/* See comments in secure_read. */
 		if (event.events & WL_POSTMASTER_DEATH)
diff --git a/src/backend/libpq/pqmq.c b/src/backend/libpq/pqmq.c
index bfe66c6..8c7fff3 100644
--- a/src/backend/libpq/pqmq.c
+++ b/src/backend/libpq/pqmq.c
@@ -17,6 +17,7 @@
 #include "libpq/pqformat.h"
 #include "libpq/pqmq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "tcop/tcopprot.h"
 #include "utils/builtins.h"
 
@@ -171,7 +172,8 @@ mq_putmessage(char msgtype, const char *s, size_t len)
 		if (result != SHM_MQ_WOULD_BLOCK)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0, WAIT_IPC,
+				  WE_MQ_PUT_MESSAGE);
 		ResetLatch(&MyProc->procLatch);
 		CHECK_FOR_INTERRUPTS();
 	}
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 1a92ca1..8558110 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -598,7 +598,8 @@ AutoVacLauncherMain(int argc, char *argv[])
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L));
+					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L),
+					   WAIT_ACTIVITY, WE_AUTOVACUUM_MAIN);
 
 		ResetLatch(MyLatch);
 
diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c
index 699c934..9bdbe68 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -16,6 +16,7 @@
 
 #include "miscadmin.h"
 #include "libpq/pqsignal.h"
+#include "pgstat.h"
 #include "postmaster/bgworker_internals.h"
 #include "postmaster/postmaster.h"
 #include "storage/barrier.h"
@@ -969,7 +970,8 @@ WaitForBackgroundWorkerStartup(BackgroundWorkerHandle *handle, pid_t *pidp)
 			break;
 
 		rc = WaitLatch(MyLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   WAIT_IPC, WE_BGWORKER_STARTUP);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
@@ -1008,7 +1010,8 @@ WaitForBackgroundWorkerShutdown(BackgroundWorkerHandle *handle)
 			break;
 
 		rc = WaitLatch(&MyProc->procLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   WAIT_IPC, WE_BGWORKER_SHUTDOWN);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index 1002034..67ec0ce 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -345,7 +345,9 @@ BackgroundWriterMain(void)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   BgWriterDelay /* ms */ );
+					   BgWriterDelay /* ms */,
+					   WAIT_ACTIVITY,
+					   WE_BGWRITER_MAIN);
 
 		/*
 		 * If no latch event and BgBufferSync says nothing's happening, extend
@@ -372,7 +374,9 @@ BackgroundWriterMain(void)
 			/* Sleep ... */
 			rc = WaitLatch(MyLatch,
 						   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-						   BgWriterDelay * HIBERNATE_FACTOR);
+						   BgWriterDelay * HIBERNATE_FACTOR,
+						   WAIT_ACTIVITY,
+						   WE_BGWRITER_HIBERNATE);
 			/* Reset the notification request in case we timed out */
 			StrategyNotifyBgWriter(-1);
 		}
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index d702a48..a382157 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -556,7 +556,9 @@ CheckpointerMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout * 1000L /* convert to ms */ );
+					   cur_timeout * 1000L /* convert to ms */,
+					   WAIT_ACTIVITY,
+					   WE_CHECKPOINTER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 1aa6466..1fc2794 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -390,7 +390,7 @@ pgarch_MainLoop(void)
 
 				rc = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							   timeout * 1000L);
+							 timeout * 1000L, WAIT_ACTIVITY, WE_ARCHIVER_MAIN);
 				if (rc & WL_TIMEOUT)
 					wakened = true;
 			}
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 96578dc..019086a 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -3155,6 +3155,18 @@ pgstat_get_wait_event_type(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_type = "BufferPin";
 			break;
+		case WAIT_ACTIVITY:
+			event_type = "Activity";
+			break;
+		case WAIT_CLIENT:
+			event_type = "Client";
+			break;
+		case WAIT_IPC:
+			event_type = "IPC";
+			break;
+		case WAIT_TIMEOUT:
+			event_type = "Timeout";
+			break;
 		default:
 			event_type = "???";
 			break;
@@ -3196,6 +3208,13 @@ pgstat_get_wait_event(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_name = "BufferPin";
 			break;
+		case WAIT_ACTIVITY:
+		case WAIT_CLIENT:
+		case WAIT_EXTENSION:
+		case WAIT_IPC:
+		case WAIT_TIMEOUT:
+			event_name = GetWaitEventIdentifier(eventId);
+			break;
 		default:
 			event_name = "unknown wait event";
 			break;
@@ -3684,8 +3703,7 @@ PgstatCollectorMain(int argc, char *argv[])
 #ifndef WIN32
 		wr = WaitLatchOrSocket(MyLatch,
 					 WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE,
-							   pgStatSock,
-							   -1L);
+					 pgStatSock, -1L, WAIT_ACTIVITY, WE_PGSTAT_MAIN);
 #else
 
 		/*
@@ -3701,7 +3719,9 @@ PgstatCollectorMain(int argc, char *argv[])
 		wr = WaitLatchOrSocket(MyLatch,
 		WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE | WL_TIMEOUT,
 							   pgStatSock,
-							   2 * 1000L /* msec */ );
+							   2 * 1000L /* msec */,
+							   WAIT_ACTIVITY,
+							   WE_PGSTAT_MAIN);
 #endif
 
 		/*
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index e7e488a..c937831 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -35,6 +35,7 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "nodes/pg_list.h"
+#include "pgstat.h"
 #include "pgtime.h"
 #include "postmaster/fork_process.h"
 #include "postmaster/postmaster.h"
@@ -424,7 +425,9 @@ SysLoggerMain(int argc, char *argv[])
 		rc = WaitLatchOrSocket(MyLatch,
 							   WL_LATCH_SET | WL_SOCKET_READABLE | cur_flags,
 							   syslogPipe[0],
-							   cur_timeout);
+							   cur_timeout,
+							   WAIT_ACTIVITY,
+							   WE_SYSLOGGER_MAIN);
 
 		if (rc & WL_SOCKET_READABLE)
 		{
@@ -475,7 +478,9 @@ SysLoggerMain(int argc, char *argv[])
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | cur_flags,
-						 cur_timeout);
+						 cur_timeout,
+						 WAIT_ACTIVITY,
+						 WE_SYSLOGGER_MAIN);
 
 		EnterCriticalSection(&sysloggerSection);
 #endif   /* WIN32 */
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index 11ec56a..e798d83 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -290,7 +290,9 @@ WalWriterMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout);
+					   cur_timeout,
+					   WAIT_ACTIVITY,
+					   WE_WAL_WRITER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index da9b7a6..8e40c34 100644
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -1286,7 +1286,9 @@ throttle(size_t increment)
 		 */
 		wait_result = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								(long) (sleep / 1000));
+								(long) (sleep / 1000),
+								WAIT_TIMEOUT,
+								WE_BASE_BACKUP_THROTTLE);
 
 		if (wait_result & WL_LATCH_SET)
 			CHECK_FOR_INTERRUPTS();
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index b442d06..09c8ce4 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -61,6 +61,7 @@
 
 #include "access/xact.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "replication/syncrep.h"
 #include "replication/walsender.h"
 #include "replication/walsender_private.h"
@@ -258,7 +259,8 @@ SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
 		 * Wait on latch.  Any condition that should wake us up will set the
 		 * latch, so no need for timeout.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1);
+		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1,
+				  WAIT_IPC, WE_SYNC_REP);
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 413ee3a..2660016 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -55,6 +55,7 @@
 #include "libpq/pqformat.h"
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "replication/walreceiver.h"
 #include "replication/walsender.h"
 #include "storage/ipc.h"
@@ -486,7 +487,9 @@ WalReceiverMain(void)
 								   WL_POSTMASTER_DEATH | WL_SOCKET_READABLE |
 									   WL_TIMEOUT | WL_LATCH_SET,
 									   wait_fd,
-									   NAPTIME_PER_CYCLE);
+									   NAPTIME_PER_CYCLE,
+									   WAIT_ACTIVITY,
+									   WE_WAL_RECEIVER_MAIN);
 				if (rc & WL_LATCH_SET)
 				{
 					ResetLatch(&walrcv->latch);
@@ -685,7 +688,8 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 		}
 		SpinLockRelease(&walrcv->mutex);
 
-		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+				  WAIT_CLIENT, WE_WAL_RECEIVER_WAIT_START);
 	}
 
 	if (update_process_title)
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index c7743da..d3f66bb 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -1146,7 +1146,9 @@ WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid,
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  WAIT_CLIENT,
+						  WE_WAL_SENDER_WRITE_DATA);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1272,7 +1274,9 @@ WalSndWaitForWal(XLogRecPtr loc)
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  WAIT_CLIENT,
+						  WE_WAL_SENDER_WAIT_WAL);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1924,7 +1928,9 @@ WalSndLoop(WalSndSendDataCallback send_data)
 
 			/* Sleep until something happens or we time out */
 			WaitLatchOrSocket(MyLatch, wakeEvents,
-							  MyProcPort->sock, sleeptime);
+							  MyProcPort->sock, sleeptime,
+							  WAIT_ACTIVITY,
+							  WE_WAL_SENDER_MAIN);
 		}
 	}
 	return;
diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c
index 9def8a1..b40c454 100644
--- a/src/backend/storage/ipc/latch.c
+++ b/src/backend/storage/ipc/latch.c
@@ -55,6 +55,7 @@
 #endif
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "portability/instr_time.h"
 #include "postmaster/postmaster.h"
 #include "storage/barrier.h"
@@ -122,6 +123,50 @@ struct WaitEventSet
 #endif
 };
 
+/*
+ * This must match enum WaitEventIdentifier!
+ */
+const char *const WaitEventNames[] = {
+	/* Activity */
+	"ArchiverMain",
+	"AutoVacuumMain",
+	"BgWriterHibernate",
+	"BgWriterMain",
+	"CheckpointerMain",
+	"PgStatMain",
+	"RecoveryWalAll",
+	"RecoveryWalStream",
+	"SysLoggerMain",
+	"WalReceiverMain",
+	"WalSenderMain",
+	"WalWriterMain",
+	/* Client */
+	"SecureRead",
+	"SecureWrite",
+	"SSLOpenServer",
+	"WalReceiverWaitStart",
+	"WalSenderWaitForWAL",
+	"WalSenderWriteData",
+	/* Extension */
+	"Extension",
+	/* IPC */
+	"BgWorkerShutdown",
+	"BgWorkerStartup",
+	"ExecuteGather",
+	"MessageQueueInternal",
+	"MessageQueuePutMessage",
+	"MessageQueueReceive",
+	"MessageQueueSend",
+	"ParallelFinish",
+	"ProcSignal",
+	"ProcSleep",
+	"SyncRep",
+	/* Timeout */
+	"BaseBackupThrottle",
+	"PgSleep",
+	"RecoveryApplyDelay",
+};
+
 #ifndef WIN32
 /* Are we currently in WaitLatch? The signal handler would like to know. */
 static volatile sig_atomic_t waiting = false;
@@ -297,9 +342,11 @@ DisownLatch(volatile Latch *latch)
  * we return all of them in one call, but we will return at least one.
  */
 int
-WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
+WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+		  uint8 classId, uint16 eventId)
 {
-	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout);
+	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout,
+							 classId, eventId);
 }
 
 /*
@@ -316,7 +363,7 @@ WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
  */
 int
 WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
-				  long timeout)
+				  long timeout, uint8 classId, uint16 eventId)
 {
 	int			ret = 0;
 	int			rc;
@@ -344,7 +391,7 @@ WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
 		AddWaitEventToSet(set, ev, sock, NULL, NULL);
 	}
 
-	rc = WaitEventSetWait(set, timeout, &event, 1);
+	rc = WaitEventSetWait(set, timeout, &event, 1, classId, eventId);
 
 	if (rc == 0)
 		ret |= WL_TIMEOUT;
@@ -863,7 +910,8 @@ WaitEventAdjustWin32(WaitEventSet *set, WaitEvent *event)
  */
 int
 WaitEventSetWait(WaitEventSet *set, long timeout,
-				 WaitEvent *occurred_events, int nevents)
+				 WaitEvent *occurred_events, int nevents,
+				 uint8 classId, uint16 eventId)
 {
 	int			returned_events = 0;
 	instr_time	start_time;
@@ -872,6 +920,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 
 	Assert(nevents > 0);
 
+	pgstat_report_wait_start(classId, eventId);
+
 	/*
 	 * Initialize timeout if requested.  We must record the current time so
 	 * that we can determine the remaining timeout if interrupted.
@@ -960,6 +1010,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 	waiting = false;
 #endif
 
+	pgstat_report_wait_end();
+
 	return returned_events;
 }
 
@@ -1491,6 +1543,22 @@ WaitEventSetWaitBlock(WaitEventSet *set, int cur_timeout,
 }
 #endif
 
+
+/*
+ * Return an identifier for a WaitEventSet depending on an event for
+ * statistics collector.
+ */
+const char *
+GetWaitEventIdentifier(uint16 eventId)
+{
+	StaticAssertStmt(lengthof(WaitEventNames) == WE_LAST_TYPE + 1,
+					 "WaitEventNames must match WaitEventIdentifiers");
+	if (eventId > WE_LAST_TYPE)
+		return "???";
+	return WaitEventNames[eventId];
+}
+
+
 /*
  * SetLatch uses SIGUSR1 to wake up the process waiting on the latch.
  *
diff --git a/src/backend/storage/ipc/shm_mq.c b/src/backend/storage/ipc/shm_mq.c
index 5b32782..8d8dc99 100644
--- a/src/backend/storage/ipc/shm_mq.c
+++ b/src/backend/storage/ipc/shm_mq.c
@@ -19,6 +19,7 @@
 #include "postgres.h"
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/bgworker.h"
 #include "storage/procsignal.h"
 #include "storage/shm_mq.h"
@@ -894,7 +895,7 @@ shm_mq_send_bytes(shm_mq_handle *mqh, Size nbytes, const void *data,
 			 * at top of loop, because setting an already-set latch is much
 			 * cheaper than setting one that has been reset.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_IPC, WE_MQ_SEND);
 
 			/* Reset the latch so we don't spin. */
 			ResetLatch(MyLatch);
@@ -991,7 +992,7 @@ shm_mq_receive_bytes(shm_mq *mq, Size bytes_needed, bool nowait,
 		 * loop, because setting an already-set latch is much cheaper than
 		 * setting one that has been reset.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_IPC, WE_MQ_RECEIVE);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
@@ -1090,7 +1091,7 @@ shm_mq_wait_internal(volatile shm_mq *mq, PGPROC *volatile * ptr,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_IPC, WE_MQ_INTERNAL);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 33e7023..ca29f14 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -39,6 +39,7 @@
 #include "access/twophase.h"
 #include "access/xact.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/autovacuum.h"
 #include "replication/slot.h"
 #include "replication/syncrep.h"
@@ -1212,7 +1213,7 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
 		}
 		else
 		{
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_IPC, WE_PROC_SLEEP);
 			ResetLatch(MyLatch);
 			/* check for deadlocks first, as that's probably log-worthy */
 			if (got_deadlock_timeout)
@@ -1724,7 +1725,7 @@ CheckDeadLockAlert(void)
 void
 ProcWaitForSignal(void)
 {
-	WaitLatch(MyLatch, WL_LATCH_SET, 0);
+	WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_IPC, WE_PROC_SIGNAL);
 	ResetLatch(MyLatch);
 	CHECK_FOR_INTERRUPTS();
 }
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 5e705e9..0e2ff93 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -30,6 +30,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "parser/scansup.h"
+#include "pgstat.h"
 #include "postmaster/syslogger.h"
 #include "rewrite/rewriteHandler.h"
 #include "storage/fd.h"
@@ -560,7 +561,9 @@ pg_sleep(PG_FUNCTION_ARGS)
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | WL_TIMEOUT,
-						 delay_ms);
+						 delay_ms,
+						 WAIT_TIMEOUT,
+						 WE_PG_SLEEP);
 		ResetLatch(MyLatch);
 	}
 
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0c98c59..b3f707e 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -721,8 +721,13 @@ typedef enum WaitClass
 	WAIT_LWLOCK_NAMED,
 	WAIT_LWLOCK_TRANCHE,
 	WAIT_LOCK,
-	WAIT_BUFFER_PIN
-}	WaitClass;
+	WAIT_BUFFER_PIN,
+	WAIT_ACTIVITY,
+	WAIT_CLIENT,
+	WAIT_EXTENSION,
+	WAIT_IPC,
+	WAIT_TIMEOUT
+} WaitClass;
 
 
 /* ----------
diff --git a/src/include/storage/latch.h b/src/include/storage/latch.h
index 5179ecc..8261830 100644
--- a/src/include/storage/latch.h
+++ b/src/include/storage/latch.h
@@ -135,6 +135,66 @@ typedef struct WaitEvent
 	void	   *user_data;		/* pointer provided in AddWaitEventToSet */
 } WaitEvent;
 
+/*
+ * List of WaitEventSet identifiers used when reporting activity to
+ * statistics collector. Up to 256 different WaitEventIdentifier can be
+ * handled. Those are classified by category first, and then by
+ * alphabetical order. Events are classified into sub-categories following
+ * some basic hierarchy rules:
+ * - "Activity" for main loops of processes waiting for an event.
+ * - "Client" for a socket awaited when a user is connected.
+ * - "IPC", similarly to "Client", for a socket awaited from another
+ *   server process.
+ * - "Timeout", for a timeout waiting to expire.
+ * - "Extension", to let extension modules a way to define a custom wait
+ *   point.
+ */
+typedef enum WaitEventIdentifier
+{
+	/* Activity */
+	WE_ARCHIVER_MAIN,
+	WE_AUTOVACUUM_MAIN,
+	WE_BGWRITER_HIBERNATE,
+	WE_BGWRITER_MAIN,
+	WE_CHECKPOINTER_MAIN,
+	WE_PGSTAT_MAIN,
+	WE_RECOVERY_WAL_ALL,
+	WE_RECOVERY_WAL_STREAM,
+	WE_SYSLOGGER_MAIN,
+	WE_WAL_RECEIVER_MAIN,
+	WE_WAL_SENDER_MAIN,
+	WE_WAL_WRITER_MAIN,
+	/* Client */
+	WE_SECURE_READ,
+	WE_SECURE_WRITE,
+	WE_SSL_OPEN_SERVER,
+	WE_WAL_RECEIVER_WAIT_START,
+	WE_WAL_SENDER_WAIT_WAL,
+	WE_WAL_SENDER_WRITE_DATA,
+	/* Extension */
+	WE_EXTENSION,
+	/* IPC */
+	WE_BGWORKER_SHUTDOWN,
+	WE_BGWORKER_STARTUP,
+	WE_EXECUTE_GATHER,
+	WE_MQ_INTERNAL,
+	WE_MQ_PUT_MESSAGE,
+	WE_MQ_RECEIVE,
+	WE_MQ_SEND,
+	WE_PARALLEL_FINISH,
+	WE_PROC_SIGNAL,
+	WE_PROC_SLEEP,
+	WE_SYNC_REP,
+	/* Timeout */
+	WE_BASE_BACKUP_THROTTLE,
+	WE_PG_SLEEP,
+	WE_RECOVERY_APPLY_DELAY
+} WaitEventIdentifier;
+
+#define WE_LAST_TYPE WE_RECOVERY_APPLY_DELAY
+
+extern const char *const WaitEventName[];
+
 /* forward declaration to avoid exposing latch.c implementation details */
 typedef struct WaitEventSet WaitEventSet;
 
@@ -155,10 +215,15 @@ extern int AddWaitEventToSet(WaitEventSet *set, uint32 events, pgsocket fd,
 				  Latch *latch, void *user_data);
 extern void ModifyWaitEvent(WaitEventSet *set, int pos, uint32 events, Latch *latch);
 
-extern int	WaitEventSetWait(WaitEventSet *set, long timeout, WaitEvent *occurred_events, int nevents);
-extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout);
+extern int	WaitEventSetWait(WaitEventSet *set, long timeout,
+				  WaitEvent *occurred_events, int nevents,
+				  uint8 classId, uint16 eventId);
+extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+				  uint8 classId, uint16 eventId);
 extern int WaitLatchOrSocket(volatile Latch *latch, int wakeEvents,
-				  pgsocket sock, long timeout);
+				  pgsocket sock, long timeout, uint8 classId,
+				  uint16 eventId);
+extern const char *GetWaitEventIdentifier(uint16 eventId);
 
 /*
  * Unix implementation uses SIGUSR1 for inter-process signaling.
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 143df4e..e7f76cd 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -16,6 +16,7 @@
 #include "postgres.h"
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/bgworker.h"
 #include "storage/procsignal.h"
 #include "storage/shm_toc.h"
@@ -279,7 +280,7 @@ wait_for_workers_to_become_ready(worker_state *wstate,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_EXTENSION, WE_EXTENSION);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/test/modules/test_shm_mq/test.c b/src/test/modules/test_shm_mq/test.c
index dd34bc7..15d3874 100644
--- a/src/test/modules/test_shm_mq/test.c
+++ b/src/test/modules/test_shm_mq/test.c
@@ -15,6 +15,7 @@
 
 #include "fmgr.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 
 #include "test_shm_mq.h"
 
@@ -230,7 +231,7 @@ test_shm_mq_pipelined(PG_FUNCTION_ARGS)
 			 * have read or written data and therefore there may now be work
 			 * for us to do.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_EXTENSION, WE_EXTENSION);
 			ResetLatch(MyLatch);
 			CHECK_FOR_INTERRUPTS();
 		}
diff --git a/src/test/modules/worker_spi/worker_spi.c b/src/test/modules/worker_spi/worker_spi.c
index 314e371..697dc42 100644
--- a/src/test/modules/worker_spi/worker_spi.c
+++ b/src/test/modules/worker_spi/worker_spi.c
@@ -227,7 +227,9 @@ worker_spi_main(Datum main_arg)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   worker_spi_naptime * 1000L);
+					   worker_spi_naptime * 1000L,
+					   WAIT_EXTENSION,
+					   WE_EXTENSION);
 		ResetLatch(MyLatch);
 
 		/* emergency bailout if postmaster has died */

diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 8ca1c1c..9265e00 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -496,7 +496,8 @@ pgfdw_get_result(PGconn *conn, const char *query)
 			wc = WaitLatchOrSocket(MyLatch,
 								   WL_LATCH_SET | WL_SOCKET_READABLE,
 								   PQsocket(conn),
-								   -1L);
+								   -1L,
+								   WE_EXTENSION);
 			ResetLatch(MyLatch);
 
 			CHECK_FOR_INTERRUPTS();
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index f400785..bb975c1 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -679,6 +679,42 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
           buffer in question.
          </para>
         </listitem>
+        <listitem>
+         <para>
+          <literal>Activity</>: The server process is idle.  This is used by
+          system processes waiting for activity in their main processing loop.
+          <literal>wait_event</> will identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Extension</>: The server process is waiting for activity
+          in an extension module.  This category is useful for modules to
+          track custom waiting points.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Client</>: The server process is waiting for some activity
+          on a socket from user applications, and that the server expects
+          something to happen that is independent from its internal processes.
+          <literal>wait_event</> will identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>IPC</>: The server process is waiting for some activity
+          from another process in the server.  <literal>wait_event</> will
+          identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Timeout</>: The server process is waiting for a timeout
+          to expire.  <literal>wait_event</> will identify the specific wait
+          point.
+         </para>
+        </listitem>
        </itemizedlist>
       </entry>
      </row>
@@ -1085,6 +1121,143 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
          <entry><literal>BufferPin</></entry>
          <entry>Waiting to acquire a pin on a buffer.</entry>
         </row>
+        <row>
+         <entry morerows="11"><literal>Activity</></entry>
+         <entry><literal>ArchiverMain</></entry>
+         <entry>Waiting in main loop of the archiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>AutoVacuumMain</></entry>
+         <entry>Waiting in main loop of autovacuum launcher process.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterHibernate</></entry>
+         <entry>Waiting in background writer process, hibernating.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterMain</></entry>
+         <entry>Waiting in main loop of background writer process background worker.</entry>
+        </row>
+        <row>
+         <entry><literal>CheckpointerMain</></entry>
+         <entry>Waiting in main loop of checkpointer process.</entry>
+        </row>
+        <row>
+         <entry><literal>PgStatMain</></entry>
+         <entry>Waiting in main loop of the statistics collector process.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalAll</></entry>
+         <entry>Waiting for WAL from any kind of source (local, archive or stream) at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalStream</></entry>
+         <entry>Waiting for WAL from a stream at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>SysLoggerMain</></entry>
+         <entry>Waiting in main loop of syslogger process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverMain</></entry>
+         <entry>Waiting in main loop of WAL receiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderMain</></entry>
+         <entry>Waiting in main loop of WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalWriterMain</></entry>
+         <entry>Waiting in main loop of WAL writer process.</entry>
+        </row>
+        <row>
+         <entry morerows="5"><literal>Client</></entry>
+         <entry><literal>SecureRead</></entry>
+         <entry>Waiting to read data from a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SecureWrite</></entry>
+         <entry>Waiting to write data to a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SSLOpenServer</></entry>
+         <entry>Waiting for SSL while attempting connection.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverWaitStart</></entry>
+         <entry>Waiting for startup process to send initial data for streaming replication.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWaitForWAL</></entry>
+         <entry>Waiting for WAL to be flushed in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWriteData</></entry>
+         <entry>Waiting for any activity when processing replies from WAL receiver in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>Extension</></entry>
+         <entry><literal>Extension</></entry>
+         <entry>Waiting in the code path of an extension, should be used by custom plugins and modules</entry>
+        </row>
+        <row>
+         <entry morerows="10"><literal>IPC</></entry>
+         <entry><literal>BgWorkerShutdown</></entry>
+         <entry>Waiting for background worker to shut down.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWorkerStartup</></entry>
+         <entry>Waiting for background worker to start up.</entry>
+        </row>
+        <row>
+         <entry><literal>ExecuteGather</></entry>
+         <entry>Waiting for activity from child process when executing <literal>Gather</> node.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueInternal</></entry>
+         <entry>Waiting for other process to be attached in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueuePutMessage</></entry>
+         <entry>Waiting to put new message in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueReceive</></entry>
+         <entry>Waiting to receive bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueSend</></entry>
+         <entry>Waiting to send bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>ParallelFinish</></entry>
+         <entry>Waiting for parallel workers to finish computing.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSignal</></entry>
+         <entry>Waiting for signal from another backend.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSleep</></entry>
+         <entry>Waiting for a specific lock.</entry>
+        </row>
+        <row>
+         <entry><literal>SyncRep</></entry>
+         <entry>Waiting for WAL commit during synchronous replication.</entry>
+        </row>
+        <row>
+         <entry morerows="2"><literal>Timeout</></entry>
+         <entry><literal>BaseBackupThrottle</></entry>
+         <entry>Waiting during base backup when throttling activity.</entry>
+        </row>
+        <row>
+         <entry><literal>PgSleep</></entry>
+         <entry>Waiting in process that called <function>pg_sleep</>.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryApplyDelay</></entry>
+         <entry>Waiting to apply WAL at recovery because it is delayed.</entry>
+        </row>
       </tbody>
      </tgroup>
     </table>
diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c
index cde0ed3..60d5c9c 100644
--- a/src/backend/access/transam/parallel.c
+++ b/src/backend/access/transam/parallel.c
@@ -540,7 +540,8 @@ WaitForParallelWorkersToFinish(ParallelContext *pcxt)
 		if (!anyone_alive)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1,
+				  WE_PARALLEL_FINISH);
 		ResetLatch(&MyProc->procLatch);
 	}
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index c1b9a97..65fe014 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5827,7 +5827,8 @@ recoveryApplyDelay(XLogReaderState *record)
 
 		WaitLatch(&XLogCtl->recoveryWakeupLatch,
 				  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-				  secs * 1000L + microsecs / 1000);
+				  secs * 1000L + microsecs / 1000,
+				  WE_RECOVERY_APPLY_DELAY);
 	}
 	return true;
 }
@@ -11387,7 +11388,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 
 						WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								  wait_time);
+							 wait_time, WE_RECOVERY_WAL_STREAM);
 						ResetLatch(&XLogCtl->recoveryWakeupLatch);
 						now = GetCurrentTimestamp();
 					}
@@ -11550,7 +11551,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					 */
 					WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							  5000L);
+							  5000L, WE_RECOVERY_WAL_ALL);
 					ResetLatch(&XLogCtl->recoveryWakeupLatch);
 					break;
 				}
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 438d1b2..b832d91 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -387,7 +387,7 @@ gather_readnext(GatherState *gatherstate)
 				return NULL;
 
 			/* Nothing to do except wait for developments. */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_EXECUTE_GATHER);
 			ResetLatch(MyLatch);
 			nvisited = 0;
 		}
diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
index fedb02c..571d4d6 100644
--- a/src/backend/libpq/be-secure-openssl.c
+++ b/src/backend/libpq/be-secure-openssl.c
@@ -419,7 +419,8 @@ aloop:
 				else
 					waitfor = WL_SOCKET_WRITEABLE;
 
-				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0);
+				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0,
+								  WE_SSL_OPEN_SERVER);
 				goto aloop;
 			case SSL_ERROR_SYSCALL:
 				if (r < 0)
diff --git a/src/backend/libpq/be-secure.c b/src/backend/libpq/be-secure.c
index cdd07d5..4e16073 100644
--- a/src/backend/libpq/be-secure.c
+++ b/src/backend/libpq/be-secure.c
@@ -146,7 +146,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 WE_SECURE_READ);
 
 		/*
 		 * If the postmaster has died, it's not safe to continue running,
@@ -247,7 +248,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 WE_SECURE_WRITE);
 
 		/* See comments in secure_read. */
 		if (event.events & WL_POSTMASTER_DEATH)
diff --git a/src/backend/libpq/pqmq.c b/src/backend/libpq/pqmq.c
index bfe66c6..280ea80 100644
--- a/src/backend/libpq/pqmq.c
+++ b/src/backend/libpq/pqmq.c
@@ -171,7 +171,8 @@ mq_putmessage(char msgtype, const char *s, size_t len)
 		if (result != SHM_MQ_WOULD_BLOCK)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0,
+				  WE_MQ_PUT_MESSAGE);
 		ResetLatch(&MyProc->procLatch);
 		CHECK_FOR_INTERRUPTS();
 	}
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 1a92ca1..019075e 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -598,7 +598,8 @@ AutoVacLauncherMain(int argc, char *argv[])
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L));
+					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L),
+					   WE_AUTOVACUUM_MAIN);
 
 		ResetLatch(MyLatch);
 
diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c
index 699c934..7da01df 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -969,7 +969,8 @@ WaitForBackgroundWorkerStartup(BackgroundWorkerHandle *handle, pid_t *pidp)
 			break;
 
 		rc = WaitLatch(MyLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   WE_BGWORKER_STARTUP);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
@@ -1008,7 +1009,8 @@ WaitForBackgroundWorkerShutdown(BackgroundWorkerHandle *handle)
 			break;
 
 		rc = WaitLatch(&MyProc->procLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   WE_BGWORKER_SHUTDOWN);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index 1002034..a89d39d 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -345,7 +345,8 @@ BackgroundWriterMain(void)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   BgWriterDelay /* ms */ );
+					   BgWriterDelay /* ms */,
+					   WE_BGWRITER_MAIN);
 
 		/*
 		 * If no latch event and BgBufferSync says nothing's happening, extend
@@ -372,7 +373,8 @@ BackgroundWriterMain(void)
 			/* Sleep ... */
 			rc = WaitLatch(MyLatch,
 						   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-						   BgWriterDelay * HIBERNATE_FACTOR);
+						   BgWriterDelay * HIBERNATE_FACTOR,
+						   WE_BGWRITER_HIBERNATE);
 			/* Reset the notification request in case we timed out */
 			StrategyNotifyBgWriter(-1);
 		}
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index d702a48..e18ef9f 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -556,7 +556,8 @@ CheckpointerMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout * 1000L /* convert to ms */ );
+					   cur_timeout * 1000L /* convert to ms */,
+					   WE_CHECKPOINTER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 1aa6466..018878c 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -390,7 +390,7 @@ pgarch_MainLoop(void)
 
 				rc = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							   timeout * 1000L);
+							 timeout * 1000L, WE_ARCHIVER_MAIN);
 				if (rc & WL_TIMEOUT)
 					wakened = true;
 			}
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 96578dc..9679b91 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -3155,6 +3155,18 @@ pgstat_get_wait_event_type(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_type = "BufferPin";
 			break;
+		case WAIT_ACTIVITY:
+			event_type = "Activity";
+			break;
+		case WAIT_CLIENT:
+			event_type = "Client";
+			break;
+		case WAIT_IPC:
+			event_type = "IPC";
+			break;
+		case WAIT_TIMEOUT:
+			event_type = "Timeout";
+			break;
 		default:
 			event_type = "???";
 			break;
@@ -3196,6 +3208,13 @@ pgstat_get_wait_event(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_name = "BufferPin";
 			break;
+		case WAIT_ACTIVITY:
+		case WAIT_CLIENT:
+		case WAIT_EXTENSION:
+		case WAIT_IPC:
+		case WAIT_TIMEOUT:
+			event_name = GetWaitEventIdentifier(eventId);
+			break;
 		default:
 			event_name = "unknown wait event";
 			break;
@@ -3684,8 +3703,7 @@ PgstatCollectorMain(int argc, char *argv[])
 #ifndef WIN32
 		wr = WaitLatchOrSocket(MyLatch,
 					 WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE,
-							   pgStatSock,
-							   -1L);
+					 pgStatSock, -1L, WE_PGSTAT_MAIN);
 #else
 
 		/*
@@ -3701,7 +3719,8 @@ PgstatCollectorMain(int argc, char *argv[])
 		wr = WaitLatchOrSocket(MyLatch,
 		WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE | WL_TIMEOUT,
 							   pgStatSock,
-							   2 * 1000L /* msec */ );
+							   2 * 1000L /* msec */,
+							   WE_PGSTAT_MAIN);
 #endif
 
 		/*
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index e7e488a..c081224 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -424,7 +424,8 @@ SysLoggerMain(int argc, char *argv[])
 		rc = WaitLatchOrSocket(MyLatch,
 							   WL_LATCH_SET | WL_SOCKET_READABLE | cur_flags,
 							   syslogPipe[0],
-							   cur_timeout);
+							   cur_timeout,
+							   WE_SYSLOGGER_MAIN);
 
 		if (rc & WL_SOCKET_READABLE)
 		{
@@ -475,7 +476,8 @@ SysLoggerMain(int argc, char *argv[])
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | cur_flags,
-						 cur_timeout);
+						 cur_timeout,
+						 WE_SYSLOGGER_MAIN);
 
 		EnterCriticalSection(&sysloggerSection);
 #endif   /* WIN32 */
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index 11ec56a..5b6fa15 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -290,7 +290,8 @@ WalWriterMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout);
+					   cur_timeout,
+					   WE_WAL_WRITER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index da9b7a6..82e8d03 100644
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -1286,7 +1286,8 @@ throttle(size_t increment)
 		 */
 		wait_result = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								(long) (sleep / 1000));
+								(long) (sleep / 1000),
+								WE_BASE_BACKUP_THROTTLE);
 
 		if (wait_result & WL_LATCH_SET)
 			CHECK_FOR_INTERRUPTS();
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index b442d06..f1acb4a 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -258,7 +258,8 @@ SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
 		 * Wait on latch.  Any condition that should wake us up will set the
 		 * latch, so no need for timeout.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1);
+		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1,
+				  WE_SYNC_REP);
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 413ee3a..046a760 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -486,7 +486,8 @@ WalReceiverMain(void)
 								   WL_POSTMASTER_DEATH | WL_SOCKET_READABLE |
 									   WL_TIMEOUT | WL_LATCH_SET,
 									   wait_fd,
-									   NAPTIME_PER_CYCLE);
+									   NAPTIME_PER_CYCLE,
+									   WE_WAL_RECEIVER_MAIN);
 				if (rc & WL_LATCH_SET)
 				{
 					ResetLatch(&walrcv->latch);
@@ -685,7 +686,8 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 		}
 		SpinLockRelease(&walrcv->mutex);
 
-		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+				  WE_WAL_RECEIVER_WAIT_START);
 	}
 
 	if (update_process_title)
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index c7743da..3cac83b 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -1146,7 +1146,8 @@ WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid,
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  WE_WAL_SENDER_WRITE_DATA);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1272,7 +1273,8 @@ WalSndWaitForWal(XLogRecPtr loc)
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  WE_WAL_SENDER_WAIT_WAL);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1924,7 +1926,8 @@ WalSndLoop(WalSndSendDataCallback send_data)
 
 			/* Sleep until something happens or we time out */
 			WaitLatchOrSocket(MyLatch, wakeEvents,
-							  MyProcPort->sock, sleeptime);
+							  MyProcPort->sock, sleeptime,
+							  WE_WAL_SENDER_MAIN);
 		}
 	}
 	return;
diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c
index 9def8a1..a0be2a7 100644
--- a/src/backend/storage/ipc/latch.c
+++ b/src/backend/storage/ipc/latch.c
@@ -55,6 +55,7 @@
 #endif
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "portability/instr_time.h"
 #include "postmaster/postmaster.h"
 #include "storage/barrier.h"
@@ -122,6 +123,50 @@ struct WaitEventSet
 #endif
 };
 
+/*
+ * This must match enum WaitEventIdentifier!
+ */
+const struct wait_event_entry WaitEventEntries[] = {
+	/* Activity */
+	{WAIT_ACTIVITY, "ArchiverMain"},
+	{WAIT_ACTIVITY, "AutoVacuumMain"},
+	{WAIT_ACTIVITY, "BgWriterHibernate"},
+	{WAIT_ACTIVITY, "BgWriterMain"},
+	{WAIT_ACTIVITY, "CheckpointerMain"},
+	{WAIT_ACTIVITY, "PgStatMain"},
+	{WAIT_ACTIVITY, "RecoveryWalAll"},
+	{WAIT_ACTIVITY, "RecoveryWalStream"},
+	{WAIT_ACTIVITY, "SysLoggerMain"},
+	{WAIT_ACTIVITY, "WalReceiverMain"},
+	{WAIT_ACTIVITY, "WalSenderMain"},
+	{WAIT_ACTIVITY, "WalWriterMain"},
+	/* Client */
+	{WAIT_CLIENT, "SecureRead"},
+	{WAIT_CLIENT, "SecureWrite"},
+	{WAIT_CLIENT, "SSLOpenServer"},
+	{WAIT_CLIENT, "WalReceiverWaitStart"},
+	{WAIT_CLIENT, "WalSenderWaitForWAL"},
+	{WAIT_CLIENT, "WalSenderWriteData"},
+	/* Extension */
+	{WAIT_EXTENSION, "Extension"},
+	/* IPC */
+	{WAIT_IPC, "BgWorkerShutdown"},
+	{WAIT_IPC, "BgWorkerStartup"},
+	{WAIT_IPC, "ExecuteGather"},
+	{WAIT_IPC, "MessageQueueInternal"},
+	{WAIT_IPC, "MessageQueuePutMessage"},
+	{WAIT_IPC, "MessageQueueReceive"},
+	{WAIT_IPC, "MessageQueueSend"},
+	{WAIT_IPC, "ParallelFinish"},
+	{WAIT_IPC, "ProcSignal"},
+	{WAIT_IPC, "ProcSleep"},
+	{WAIT_IPC, "SyncRep"},
+	/* Timeout */
+	{WAIT_TIMEOUT, "BaseBackupThrottle"},
+	{WAIT_TIMEOUT, "PgSleep"},
+	{WAIT_TIMEOUT, "RecoveryApplyDelay"},
+};
+
 #ifndef WIN32
 /* Are we currently in WaitLatch? The signal handler would like to know. */
 static volatile sig_atomic_t waiting = false;
@@ -297,9 +342,11 @@ DisownLatch(volatile Latch *latch)
  * we return all of them in one call, but we will return at least one.
  */
 int
-WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
+WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+		  uint16 eventId)
 {
-	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout);
+	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout,
+							 eventId);
 }
 
 /*
@@ -316,7 +363,7 @@ WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
  */
 int
 WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
-				  long timeout)
+				  long timeout, uint16 eventId)
 {
 	int			ret = 0;
 	int			rc;
@@ -344,7 +391,7 @@ WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
 		AddWaitEventToSet(set, ev, sock, NULL, NULL);
 	}
 
-	rc = WaitEventSetWait(set, timeout, &event, 1);
+	rc = WaitEventSetWait(set, timeout, &event, 1, eventId);
 
 	if (rc == 0)
 		ret |= WL_TIMEOUT;
@@ -863,7 +910,8 @@ WaitEventAdjustWin32(WaitEventSet *set, WaitEvent *event)
  */
 int
 WaitEventSetWait(WaitEventSet *set, long timeout,
-				 WaitEvent *occurred_events, int nevents)
+				 WaitEvent *occurred_events, int nevents,
+				 uint16 eventId)
 {
 	int			returned_events = 0;
 	instr_time	start_time;
@@ -872,6 +920,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 
 	Assert(nevents > 0);
 
+	pgstat_report_wait_start(GetWaitEventClass(eventId), eventId);
+
 	/*
 	 * Initialize timeout if requested.  We must record the current time so
 	 * that we can determine the remaining timeout if interrupted.
@@ -960,6 +1010,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 	waiting = false;
 #endif
 
+	pgstat_report_wait_end();
+
 	return returned_events;
 }
 
@@ -1491,6 +1543,37 @@ WaitEventSetWaitBlock(WaitEventSet *set, int cur_timeout,
 }
 #endif
 
+
+/*
+ * Return an event name for a WaitEventSet event depending on the ID
+ * provided by caller, ID used for the statistics collector.
+ */
+const char *
+GetWaitEventIdentifier(uint16 eventId)
+{
+	StaticAssertStmt(lengthof(WaitEventEntries) == WE_LAST_TYPE + 1,
+					 "WaitEventEntries must match WaitEventIdentifiers");
+	if (eventId > WE_LAST_TYPE)
+		return "???";
+	return WaitEventEntries[eventId].name;
+}
+
+
+/*
+ * Determine the class ID of a WaitEventSet event depending on the ID
+ * provided by caller, ID used for the statistics collector.
+ */
+uint8
+GetWaitEventClass(uint16 eventId)
+{
+	StaticAssertStmt(lengthof(WaitEventEntries) == WE_LAST_TYPE + 1,
+					 "WaitEventEntries must match WaitEventIdentifiers");
+	if (eventId > WE_LAST_TYPE)
+		return WAIT_UNDEFINED;
+	return WaitEventEntries[eventId].classId;
+}
+
+
 /*
  * SetLatch uses SIGUSR1 to wake up the process waiting on the latch.
  *
diff --git a/src/backend/storage/ipc/shm_mq.c b/src/backend/storage/ipc/shm_mq.c
index 5b32782..c47cf2b 100644
--- a/src/backend/storage/ipc/shm_mq.c
+++ b/src/backend/storage/ipc/shm_mq.c
@@ -894,7 +894,7 @@ shm_mq_send_bytes(shm_mq_handle *mqh, Size nbytes, const void *data,
 			 * at top of loop, because setting an already-set latch is much
 			 * cheaper than setting one that has been reset.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_MQ_SEND);
 
 			/* Reset the latch so we don't spin. */
 			ResetLatch(MyLatch);
@@ -991,7 +991,7 @@ shm_mq_receive_bytes(shm_mq *mq, Size bytes_needed, bool nowait,
 		 * loop, because setting an already-set latch is much cheaper than
 		 * setting one that has been reset.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_MQ_RECEIVE);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
@@ -1090,7 +1090,7 @@ shm_mq_wait_internal(volatile shm_mq *mq, PGPROC *volatile * ptr,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_MQ_INTERNAL);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 33e7023..23deeb6 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -1212,7 +1212,7 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
 		}
 		else
 		{
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_PROC_SLEEP);
 			ResetLatch(MyLatch);
 			/* check for deadlocks first, as that's probably log-worthy */
 			if (got_deadlock_timeout)
@@ -1724,7 +1724,7 @@ CheckDeadLockAlert(void)
 void
 ProcWaitForSignal(void)
 {
-	WaitLatch(MyLatch, WL_LATCH_SET, 0);
+	WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_PROC_SIGNAL);
 	ResetLatch(MyLatch);
 	CHECK_FOR_INTERRUPTS();
 }
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 5e705e9..642f619 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -560,7 +560,8 @@ pg_sleep(PG_FUNCTION_ARGS)
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | WL_TIMEOUT,
-						 delay_ms);
+						 delay_ms,
+						 WE_PG_SLEEP);
 		ResetLatch(MyLatch);
 	}
 
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0c98c59..b3f707e 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -721,8 +721,13 @@ typedef enum WaitClass
 	WAIT_LWLOCK_NAMED,
 	WAIT_LWLOCK_TRANCHE,
 	WAIT_LOCK,
-	WAIT_BUFFER_PIN
-}	WaitClass;
+	WAIT_BUFFER_PIN,
+	WAIT_ACTIVITY,
+	WAIT_CLIENT,
+	WAIT_EXTENSION,
+	WAIT_IPC,
+	WAIT_TIMEOUT
+} WaitClass;
 
 
 /* ----------
diff --git a/src/include/storage/latch.h b/src/include/storage/latch.h
index 5179ecc..c4ad1cb 100644
--- a/src/include/storage/latch.h
+++ b/src/include/storage/latch.h
@@ -135,6 +135,75 @@ typedef struct WaitEvent
 	void	   *user_data;		/* pointer provided in AddWaitEventToSet */
 } WaitEvent;
 
+/*
+ * List of WaitEventSet identifiers used when reporting activity to
+ * statistics collector. Up to 256 different WaitEventIdentifier can be
+ * handled. Those are classified by category first, and then by
+ * alphabetical order. Events are classified into sub-categories following
+ * some basic hierarchy rules:
+ * - "Activity" for main loops of processes waiting for an event.
+ * - "Client" for a socket awaited when a user is connected.
+ * - "IPC", similarly to "Client", for a socket awaited from another
+ *   server process.
+ * - "Timeout", for a timeout waiting to expire.
+ * - "Extension", to let extension modules a way to define a custom wait
+ *   point.
+ */
+typedef enum WaitEventIdentifier
+{
+	/* Activity */
+	WE_ARCHIVER_MAIN,
+	WE_AUTOVACUUM_MAIN,
+	WE_BGWRITER_HIBERNATE,
+	WE_BGWRITER_MAIN,
+	WE_CHECKPOINTER_MAIN,
+	WE_PGSTAT_MAIN,
+	WE_RECOVERY_WAL_ALL,
+	WE_RECOVERY_WAL_STREAM,
+	WE_SYSLOGGER_MAIN,
+	WE_WAL_RECEIVER_MAIN,
+	WE_WAL_SENDER_MAIN,
+	WE_WAL_WRITER_MAIN,
+	/* Client */
+	WE_SECURE_READ,
+	WE_SECURE_WRITE,
+	WE_SSL_OPEN_SERVER,
+	WE_WAL_RECEIVER_WAIT_START,
+	WE_WAL_SENDER_WAIT_WAL,
+	WE_WAL_SENDER_WRITE_DATA,
+	/* Extension */
+	WE_EXTENSION,
+	/* IPC */
+	WE_BGWORKER_SHUTDOWN,
+	WE_BGWORKER_STARTUP,
+	WE_EXECUTE_GATHER,
+	WE_MQ_INTERNAL,
+	WE_MQ_PUT_MESSAGE,
+	WE_MQ_RECEIVE,
+	WE_MQ_SEND,
+	WE_PARALLEL_FINISH,
+	WE_PROC_SIGNAL,
+	WE_PROC_SLEEP,
+	WE_SYNC_REP,
+	/* Timeout */
+	WE_BASE_BACKUP_THROTTLE,
+	WE_PG_SLEEP,
+	WE_RECOVERY_APPLY_DELAY
+} WaitEventIdentifier;
+
+#define WE_LAST_TYPE WE_RECOVERY_APPLY_DELAY
+
+/*
+ * The information details about each WaitEventIdentifier listed above
+ * are specified by an array of name-pair values.
+ */
+struct wait_event_entry
+{
+	uint8       classId;
+	const char *name;
+};
+extern const struct wait_event_entry WaitEventEntries[];
+
 /* forward declaration to avoid exposing latch.c implementation details */
 typedef struct WaitEventSet WaitEventSet;
 
@@ -155,10 +224,15 @@ extern int AddWaitEventToSet(WaitEventSet *set, uint32 events, pgsocket fd,
 				  Latch *latch, void *user_data);
 extern void ModifyWaitEvent(WaitEventSet *set, int pos, uint32 events, Latch *latch);
 
-extern int	WaitEventSetWait(WaitEventSet *set, long timeout, WaitEvent *occurred_events, int nevents);
-extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout);
+extern int	WaitEventSetWait(WaitEventSet *set, long timeout,
+				  WaitEvent *occurred_events, int nevents,
+				  uint16 eventId);
+extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+				  uint16 eventId);
 extern int WaitLatchOrSocket(volatile Latch *latch, int wakeEvents,
-				  pgsocket sock, long timeout);
+				  pgsocket sock, long timeout, uint16 eventId);
+extern uint8 GetWaitEventClass(uint16 eventId);
+extern const char *GetWaitEventIdentifier(uint16 eventId);
 
 /*
  * Unix implementation uses SIGUSR1 for inter-process signaling.
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 143df4e..adebfc8 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -279,7 +279,7 @@ wait_for_workers_to_become_ready(worker_state *wstate,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_EXTENSION);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/test/modules/test_shm_mq/test.c b/src/test/modules/test_shm_mq/test.c
index dd34bc7..22145db 100644
--- a/src/test/modules/test_shm_mq/test.c
+++ b/src/test/modules/test_shm_mq/test.c
@@ -230,7 +230,7 @@ test_shm_mq_pipelined(PG_FUNCTION_ARGS)
 			 * have read or written data and therefore there may now be work
 			 * for us to do.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WE_EXTENSION);
 			ResetLatch(MyLatch);
 			CHECK_FOR_INTERRUPTS();
 		}
diff --git a/src/test/modules/worker_spi/worker_spi.c b/src/test/modules/worker_spi/worker_spi.c
index 7c9a3eb..9673b20 100644
--- a/src/test/modules/worker_spi/worker_spi.c
+++ b/src/test/modules/worker_spi/worker_spi.c
@@ -227,7 +227,8 @@ worker_spi_main(Datum main_arg)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   worker_spi_naptime * 1000L);
+					   worker_spi_naptime * 1000L,
+					   WE_EXTENSION);
 		ResetLatch(MyLatch);
 
 		/* emergency bailout if postmaster has died */

diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 8ca1c1c..0841fd7 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -17,6 +17,7 @@
 #include "access/xact.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "storage/latch.h"
 #include "utils/hsearch.h"
 #include "utils/memutils.h"
@@ -491,12 +492,18 @@ pgfdw_get_result(PGconn *conn, const char *query)
 		while (PQisBusy(conn))
 		{
 			int			wc;
+			uint32		wait_event;
+
+			/* Define event to wait for */
+			wait_event = pgstat_make_wait_event(WAIT_EXTENSION,
+												WAIT_EVENT_EXTENSION);
 
 			/* Sleep until there's something to do */
 			wc = WaitLatchOrSocket(MyLatch,
 								   WL_LATCH_SET | WL_SOCKET_READABLE,
 								   PQsocket(conn),
-								   -1L);
+								   -1L,
+								   wait_event);
 			ResetLatch(MyLatch);
 
 			CHECK_FOR_INTERRUPTS();
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index f400785..bb975c1 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -679,6 +679,42 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
           buffer in question.
          </para>
         </listitem>
+        <listitem>
+         <para>
+          <literal>Activity</>: The server process is idle.  This is used by
+          system processes waiting for activity in their main processing loop.
+          <literal>wait_event</> will identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Extension</>: The server process is waiting for activity
+          in an extension module.  This category is useful for modules to
+          track custom waiting points.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Client</>: The server process is waiting for some activity
+          on a socket from user applications, and that the server expects
+          something to happen that is independent from its internal processes.
+          <literal>wait_event</> will identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>IPC</>: The server process is waiting for some activity
+          from another process in the server.  <literal>wait_event</> will
+          identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Timeout</>: The server process is waiting for a timeout
+          to expire.  <literal>wait_event</> will identify the specific wait
+          point.
+         </para>
+        </listitem>
        </itemizedlist>
       </entry>
      </row>
@@ -1085,6 +1121,143 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
          <entry><literal>BufferPin</></entry>
          <entry>Waiting to acquire a pin on a buffer.</entry>
         </row>
+        <row>
+         <entry morerows="11"><literal>Activity</></entry>
+         <entry><literal>ArchiverMain</></entry>
+         <entry>Waiting in main loop of the archiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>AutoVacuumMain</></entry>
+         <entry>Waiting in main loop of autovacuum launcher process.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterHibernate</></entry>
+         <entry>Waiting in background writer process, hibernating.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterMain</></entry>
+         <entry>Waiting in main loop of background writer process background worker.</entry>
+        </row>
+        <row>
+         <entry><literal>CheckpointerMain</></entry>
+         <entry>Waiting in main loop of checkpointer process.</entry>
+        </row>
+        <row>
+         <entry><literal>PgStatMain</></entry>
+         <entry>Waiting in main loop of the statistics collector process.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalAll</></entry>
+         <entry>Waiting for WAL from any kind of source (local, archive or stream) at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalStream</></entry>
+         <entry>Waiting for WAL from a stream at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>SysLoggerMain</></entry>
+         <entry>Waiting in main loop of syslogger process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverMain</></entry>
+         <entry>Waiting in main loop of WAL receiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderMain</></entry>
+         <entry>Waiting in main loop of WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalWriterMain</></entry>
+         <entry>Waiting in main loop of WAL writer process.</entry>
+        </row>
+        <row>
+         <entry morerows="5"><literal>Client</></entry>
+         <entry><literal>SecureRead</></entry>
+         <entry>Waiting to read data from a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SecureWrite</></entry>
+         <entry>Waiting to write data to a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SSLOpenServer</></entry>
+         <entry>Waiting for SSL while attempting connection.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverWaitStart</></entry>
+         <entry>Waiting for startup process to send initial data for streaming replication.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWaitForWAL</></entry>
+         <entry>Waiting for WAL to be flushed in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWriteData</></entry>
+         <entry>Waiting for any activity when processing replies from WAL receiver in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>Extension</></entry>
+         <entry><literal>Extension</></entry>
+         <entry>Waiting in the code path of an extension, should be used by custom plugins and modules</entry>
+        </row>
+        <row>
+         <entry morerows="10"><literal>IPC</></entry>
+         <entry><literal>BgWorkerShutdown</></entry>
+         <entry>Waiting for background worker to shut down.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWorkerStartup</></entry>
+         <entry>Waiting for background worker to start up.</entry>
+        </row>
+        <row>
+         <entry><literal>ExecuteGather</></entry>
+         <entry>Waiting for activity from child process when executing <literal>Gather</> node.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueInternal</></entry>
+         <entry>Waiting for other process to be attached in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueuePutMessage</></entry>
+         <entry>Waiting to put new message in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueReceive</></entry>
+         <entry>Waiting to receive bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueSend</></entry>
+         <entry>Waiting to send bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>ParallelFinish</></entry>
+         <entry>Waiting for parallel workers to finish computing.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSignal</></entry>
+         <entry>Waiting for signal from another backend.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSleep</></entry>
+         <entry>Waiting for a specific lock.</entry>
+        </row>
+        <row>
+         <entry><literal>SyncRep</></entry>
+         <entry>Waiting for WAL commit during synchronous replication.</entry>
+        </row>
+        <row>
+         <entry morerows="2"><literal>Timeout</></entry>
+         <entry><literal>BaseBackupThrottle</></entry>
+         <entry>Waiting during base backup when throttling activity.</entry>
+        </row>
+        <row>
+         <entry><literal>PgSleep</></entry>
+         <entry>Waiting in process that called <function>pg_sleep</>.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryApplyDelay</></entry>
+         <entry>Waiting to apply WAL at recovery because it is delayed.</entry>
+        </row>
       </tbody>
      </tgroup>
     </table>
diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c
index cde0ed3..58843ec 100644
--- a/src/backend/access/transam/parallel.c
+++ b/src/backend/access/transam/parallel.c
@@ -23,6 +23,7 @@
 #include "libpq/pqformat.h"
 #include "libpq/pqmq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "optimizer/planmain.h"
 #include "storage/ipc.h"
 #include "storage/sinval.h"
@@ -540,7 +541,9 @@ WaitForParallelWorkersToFinish(ParallelContext *pcxt)
 		if (!anyone_alive)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1,
+				  pgstat_make_wait_event(WAIT_IPC,
+										 WAIT_EVENT_PARALLEL_FINISH));
 		ResetLatch(&MyProc->procLatch);
 	}
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index c1b9a97..52362d6 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5827,7 +5827,9 @@ recoveryApplyDelay(XLogReaderState *record)
 
 		WaitLatch(&XLogCtl->recoveryWakeupLatch,
 				  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-				  secs * 1000L + microsecs / 1000);
+				  secs * 1000L + microsecs / 1000,
+				  pgstat_make_wait_event(WAIT_TIMEOUT,
+										 WAIT_EVENT_RECOVERY_APPLY_DELAY));
 	}
 	return true;
 }
@@ -11380,14 +11382,19 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 						long		secs,
 									wait_time;
 						int			usecs;
+						uint32		wait_event;
 
 						TimestampDifference(last_fail_time, now, &secs, &usecs);
 						wait_time = wal_retrieve_retry_interval -
 							(secs * 1000 + usecs / 1000);
+						wait_event = pgstat_make_wait_event(WAIT_ACTIVITY,
+											WAIT_EVENT_RECOVERY_APPLY_DELAY);
 
 						WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								  wait_time);
+							 wait_time,
+							 wait_event);
+
 						ResetLatch(&XLogCtl->recoveryWakeupLatch);
 						now = GetCurrentTimestamp();
 					}
@@ -11550,7 +11557,9 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					 */
 					WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							  5000L);
+							  5000L,
+							  pgstat_make_wait_event(WAIT_ACTIVITY,
+												WAIT_EVENT_RECOVERY_WAL_ALL));
 					ResetLatch(&XLogCtl->recoveryWakeupLatch);
 					break;
 				}
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 438d1b2..1a7b303 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -38,6 +38,7 @@
 #include "executor/nodeSubplan.h"
 #include "executor/tqueue.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "utils/memutils.h"
 #include "utils/rel.h"
 
@@ -387,7 +388,9 @@ gather_readnext(GatherState *gatherstate)
 				return NULL;
 
 			/* Nothing to do except wait for developments. */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0,
+					  pgstat_make_wait_event(WAIT_IPC,
+											 WAIT_EVENT_EXECUTE_GATHER));
 			ResetLatch(MyLatch);
 			nvisited = 0;
 		}
diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
index fedb02c..bc87a47 100644
--- a/src/backend/libpq/be-secure-openssl.c
+++ b/src/backend/libpq/be-secure-openssl.c
@@ -60,6 +60,7 @@
 
 #include "libpq/libpq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "storage/latch.h"
 #include "tcop/tcopprot.h"
 #include "utils/memutils.h"
@@ -419,7 +420,9 @@ aloop:
 				else
 					waitfor = WL_SOCKET_WRITEABLE;
 
-				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0);
+				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0,
+						  pgstat_make_wait_event(WAIT_CLIENT,
+												 WAIT_EVENT_SSL_OPEN_SERVER));
 				goto aloop;
 			case SSL_ERROR_SYSCALL:
 				if (r < 0)
diff --git a/src/backend/libpq/be-secure.c b/src/backend/libpq/be-secure.c
index cdd07d5..9f89491 100644
--- a/src/backend/libpq/be-secure.c
+++ b/src/backend/libpq/be-secure.c
@@ -33,6 +33,7 @@
 
 #include "libpq/libpq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "tcop/tcopprot.h"
 #include "utils/memutils.h"
 #include "storage/ipc.h"
@@ -146,7 +147,9 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 pgstat_make_wait_event(WAIT_CLIENT,
+												WAIT_EVENT_SECURE_READ));
 
 		/*
 		 * If the postmaster has died, it's not safe to continue running,
@@ -247,7 +250,9 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 pgstat_make_wait_event(WAIT_CLIENT,
+												WAIT_EVENT_SECURE_WRITE));
 
 		/* See comments in secure_read. */
 		if (event.events & WL_POSTMASTER_DEATH)
diff --git a/src/backend/libpq/pqmq.c b/src/backend/libpq/pqmq.c
index bfe66c6..5121335 100644
--- a/src/backend/libpq/pqmq.c
+++ b/src/backend/libpq/pqmq.c
@@ -17,6 +17,7 @@
 #include "libpq/pqformat.h"
 #include "libpq/pqmq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "tcop/tcopprot.h"
 #include "utils/builtins.h"
 
@@ -171,7 +172,9 @@ mq_putmessage(char msgtype, const char *s, size_t len)
 		if (result != SHM_MQ_WOULD_BLOCK)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0,
+				  pgstat_make_wait_event(WAIT_IPC,
+										 WAIT_EVENT_MQ_PUT_MESSAGE));
 		ResetLatch(&MyProc->procLatch);
 		CHECK_FOR_INTERRUPTS();
 	}
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 1a92ca1..93e4567 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -598,7 +598,9 @@ AutoVacLauncherMain(int argc, char *argv[])
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L));
+					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L),
+					   pgstat_make_wait_event(WAIT_ACTIVITY,
+											  WAIT_EVENT_AUTOVACUUM_MAIN));
 
 		ResetLatch(MyLatch);
 
diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c
index 699c934..62ce3c8 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -16,6 +16,7 @@
 
 #include "miscadmin.h"
 #include "libpq/pqsignal.h"
+#include "pgstat.h"
 #include "postmaster/bgworker_internals.h"
 #include "postmaster/postmaster.h"
 #include "storage/barrier.h"
@@ -969,7 +970,9 @@ WaitForBackgroundWorkerStartup(BackgroundWorkerHandle *handle, pid_t *pidp)
 			break;
 
 		rc = WaitLatch(MyLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   pgstat_make_wait_event(WAIT_IPC,
+											  WAIT_EVENT_BGWORKER_STARTUP));
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
@@ -1008,7 +1011,9 @@ WaitForBackgroundWorkerShutdown(BackgroundWorkerHandle *handle)
 			break;
 
 		rc = WaitLatch(&MyProc->procLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   pgstat_make_wait_event(WAIT_IPC,
+											  WAIT_EVENT_BGWORKER_SHUTDOWN));
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index 1002034..8683323 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -345,7 +345,9 @@ BackgroundWriterMain(void)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   BgWriterDelay /* ms */ );
+					   BgWriterDelay /* ms */,
+					   pgstat_make_wait_event(WAIT_ACTIVITY,
+											  WAIT_EVENT_BGWRITER_MAIN));
 
 		/*
 		 * If no latch event and BgBufferSync says nothing's happening, extend
@@ -371,8 +373,10 @@ BackgroundWriterMain(void)
 			StrategyNotifyBgWriter(MyProc->pgprocno);
 			/* Sleep ... */
 			rc = WaitLatch(MyLatch,
-						   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-						   BgWriterDelay * HIBERNATE_FACTOR);
+				   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
+				   BgWriterDelay * HIBERNATE_FACTOR,
+				   pgstat_make_wait_event(WAIT_ACTIVITY,
+										  WAIT_EVENT_BGWRITER_HIBERNATE));
 			/* Reset the notification request in case we timed out */
 			StrategyNotifyBgWriter(-1);
 		}
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index d702a48..512ce20 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -556,7 +556,9 @@ CheckpointerMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout * 1000L /* convert to ms */ );
+					   cur_timeout * 1000L /* convert to ms */,
+					   pgstat_make_wait_event(WAIT_ACTIVITY,
+											  WAIT_EVENT_CHECKPOINTER_MAIN));
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 1aa6466..249674f 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -390,7 +390,9 @@ pgarch_MainLoop(void)
 
 				rc = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							   timeout * 1000L);
+							 timeout * 1000L,
+							 pgstat_make_wait_event(WAIT_ACTIVITY,
+													WAIT_EVENT_ARCHIVER_MAIN));
 				if (rc & WL_TIMEOUT)
 					wakened = true;
 			}
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 96578dc..97fd4ea 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -3155,6 +3155,18 @@ pgstat_get_wait_event_type(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_type = "BufferPin";
 			break;
+		case WAIT_ACTIVITY:
+			event_type = "Activity";
+			break;
+		case WAIT_CLIENT:
+			event_type = "Client";
+			break;
+		case WAIT_IPC:
+			event_type = "IPC";
+			break;
+		case WAIT_TIMEOUT:
+			event_type = "Timeout";
+			break;
 		default:
 			event_type = "???";
 			break;
@@ -3196,6 +3208,13 @@ pgstat_get_wait_event(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_name = "BufferPin";
 			break;
+		case WAIT_ACTIVITY:
+		case WAIT_CLIENT:
+		case WAIT_EXTENSION:
+		case WAIT_IPC:
+		case WAIT_TIMEOUT:
+			event_name = GetWaitEventIdentifier(eventId);
+			break;
 		default:
 			event_name = "unknown wait event";
 			break;
@@ -3684,8 +3703,9 @@ PgstatCollectorMain(int argc, char *argv[])
 #ifndef WIN32
 		wr = WaitLatchOrSocket(MyLatch,
 					 WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE,
-							   pgStatSock,
-							   -1L);
+					 pgStatSock, -1L,
+					 pgstat_make_wait_event(WAIT_ACTIVITY,
+											WAIT_EVENT_PGSTAT_MAIN));
 #else
 
 		/*
@@ -3700,8 +3720,10 @@ PgstatCollectorMain(int argc, char *argv[])
 		 */
 		wr = WaitLatchOrSocket(MyLatch,
 		WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE | WL_TIMEOUT,
-							   pgStatSock,
-							   2 * 1000L /* msec */ );
+					 pgStatSock,
+					 2 * 1000L /* msec */,
+					 pgstat_make_wait_event(WAIT_ACTIVITY,
+											WAIT_EVENT_PGSTAT_MAIN));
 #endif
 
 		/*
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index e7e488a..5658454 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -34,6 +34,7 @@
 #include "lib/stringinfo.h"
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "nodes/pg_list.h"
 #include "pgtime.h"
 #include "postmaster/fork_process.h"
@@ -424,7 +425,9 @@ SysLoggerMain(int argc, char *argv[])
 		rc = WaitLatchOrSocket(MyLatch,
 							   WL_LATCH_SET | WL_SOCKET_READABLE | cur_flags,
 							   syslogPipe[0],
-							   cur_timeout);
+							   cur_timeout,
+					   pgstat_make_wait_event(WAIT_ACTIVITY,
+											  WAIT_EVENT_SYSLOGGER_MAIN));
 
 		if (rc & WL_SOCKET_READABLE)
 		{
@@ -475,7 +478,9 @@ SysLoggerMain(int argc, char *argv[])
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | cur_flags,
-						 cur_timeout);
+						 cur_timeout,
+						 pgstat_make_wait_event(WAIT_ACTIVITY,
+												WAIT_EVENT_SYSLOGGER_MAIN));
 
 		EnterCriticalSection(&sysloggerSection);
 #endif   /* WIN32 */
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index 11ec56a..1b31582 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -290,7 +290,9 @@ WalWriterMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout);
+					   cur_timeout,
+					   pgstat_make_wait_event(WAIT_ACTIVITY,
+											  WAIT_EVENT_WAL_WRITER_MAIN));
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index 1eabaef..76571e5 100644
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -1363,8 +1363,10 @@ throttle(size_t increment)
 		 * the maximum time to sleep. Thus the cast to long is safe.
 		 */
 		wait_result = WaitLatch(MyLatch,
-							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								(long) (sleep / 1000));
+					WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
+					(long) (sleep / 1000),
+					pgstat_make_wait_event(WAIT_TIMEOUT,
+										   WAIT_EVENT_BASE_BACKUP_THROTTLE));
 
 		if (wait_result & WL_LATCH_SET)
 			CHECK_FOR_INTERRUPTS();
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index b442d06..47e33b1 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -61,6 +61,7 @@
 
 #include "access/xact.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "replication/syncrep.h"
 #include "replication/walsender.h"
 #include "replication/walsender_private.h"
@@ -258,7 +259,9 @@ SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
 		 * Wait on latch.  Any condition that should wake us up will set the
 		 * latch, so no need for timeout.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1);
+		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1,
+				  pgstat_make_wait_event(WAIT_IPC,
+										 WAIT_EVENT_SYNC_REP));
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 413ee3a..f7839c9 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -55,6 +55,7 @@
 #include "libpq/pqformat.h"
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "replication/walreceiver.h"
 #include "replication/walsender.h"
 #include "storage/ipc.h"
@@ -401,6 +402,7 @@ WalReceiverMain(void)
 				bool		endofwal = false;
 				pgsocket	wait_fd = PGINVALID_SOCKET;
 				int			rc;
+				uint32		wait_event;
 
 				/*
 				 * Exit walreceiver if we're not in recovery. This should not
@@ -482,11 +484,15 @@ WalReceiverMain(void)
 				 * avoiding some system calls.
 				 */
 				Assert(wait_fd != PGINVALID_SOCKET);
+				wait_event = pgstat_make_wait_event(WAIT_ACTIVITY,
+										  WAIT_EVENT_WAL_RECEIVER_MAIN);
 				rc = WaitLatchOrSocket(&walrcv->latch,
 								   WL_POSTMASTER_DEATH | WL_SOCKET_READABLE |
 									   WL_TIMEOUT | WL_LATCH_SET,
 									   wait_fd,
-									   NAPTIME_PER_CYCLE);
+									   NAPTIME_PER_CYCLE,
+									   wait_event);
+
 				if (rc & WL_LATCH_SET)
 				{
 					ResetLatch(&walrcv->latch);
@@ -685,7 +691,9 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 		}
 		SpinLockRelease(&walrcv->mutex);
 
-		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+				  pgstat_make_wait_event(WAIT_CLIENT,
+										 WAIT_EVENT_WAL_RECEIVER_WAIT_START));
 	}
 
 	if (update_process_title)
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index c7743da..715785c 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -1146,7 +1146,9 @@ WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid,
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  pgstat_make_wait_event(WAIT_CLIENT,
+										 WAIT_EVENT_WAL_SENDER_WRITE_DATA));
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1272,7 +1274,9 @@ WalSndWaitForWal(XLogRecPtr loc)
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  pgstat_make_wait_event(WAIT_CLIENT,
+										 WAIT_EVENT_WAL_SENDER_WAIT_WAL));
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1924,7 +1928,9 @@ WalSndLoop(WalSndSendDataCallback send_data)
 
 			/* Sleep until something happens or we time out */
 			WaitLatchOrSocket(MyLatch, wakeEvents,
-							  MyProcPort->sock, sleeptime);
+							  MyProcPort->sock, sleeptime,
+							  pgstat_make_wait_event(WAIT_ACTIVITY,
+										 WAIT_EVENT_WAL_SENDER_MAIN));
 		}
 	}
 	return;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 90804a3..84715ae 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -3610,6 +3610,7 @@ LockBufferForCleanup(Buffer buffer)
 	for (;;)
 	{
 		uint32		buf_state;
+		uint32		wait_event;
 
 		/* Try to acquire lock */
 		LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
@@ -3635,8 +3636,8 @@ LockBufferForCleanup(Buffer buffer)
 		UnlockBufHdr(bufHdr, buf_state);
 		LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
 
-		/* Report the wait */
-		pgstat_report_wait_start(WAIT_BUFFER_PIN, 0);
+		/* Define the event to wait for */
+		wait_event = pgstat_make_wait_event(WAIT_BUFFER_PIN, 0);
 
 		/* Wait to be signaled by UnpinBuffer() */
 		if (InHotStandby)
@@ -3644,14 +3645,12 @@ LockBufferForCleanup(Buffer buffer)
 			/* Publish the bufid that Startup process waits on */
 			SetStartupBufferPinWaitBufId(buffer - 1);
 			/* Set alarm and then wait to be signaled by UnpinBuffer() */
-			ResolveRecoveryConflictWithBufferPin();
+			ResolveRecoveryConflictWithBufferPin(wait_event);
 			/* Reset the published bufid */
 			SetStartupBufferPinWaitBufId(-1);
 		}
 		else
-			ProcWaitForSignal();
-
-		pgstat_report_wait_end();
+			ProcWaitForSignal(wait_event);
 
 		/*
 		 * Remove flag marking us as waiter. Normally this will not be set
diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c
index 9def8a1..b91568b 100644
--- a/src/backend/storage/ipc/latch.c
+++ b/src/backend/storage/ipc/latch.c
@@ -55,6 +55,7 @@
 #endif
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "portability/instr_time.h"
 #include "postmaster/postmaster.h"
 #include "storage/barrier.h"
@@ -122,6 +123,50 @@ struct WaitEventSet
 #endif
 };
 
+/*
+ * This must match enum WaitEventIdentifier!
+ */
+const char *const WaitEventNames[] = {
+	/* Activity */
+	"ArchiverMain",
+	"AutoVacuumMain",
+	"BgWriterHibernate",
+	"BgWriterMain",
+	"CheckpointerMain",
+	"PgStatMain",
+	"RecoveryWalAll",
+	"RecoveryWalStream",
+	"SysLoggerMain",
+	"WalReceiverMain",
+	"WalSenderMain",
+	"WalWriterMain",
+	/* Client */
+	"SecureRead",
+	"SecureWrite",
+	"SSLOpenServer",
+	"WalReceiverWaitStart",
+	"WalSenderWaitForWAL",
+	"WalSenderWriteData",
+	/* Extension */
+	"Extension",
+	/* IPC */
+	"BgWorkerShutdown",
+	"BgWorkerStartup",
+	"ExecuteGather",
+	"MessageQueueInternal",
+	"MessageQueuePutMessage",
+	"MessageQueueReceive",
+	"MessageQueueSend",
+	"ParallelFinish",
+	"ProcSignal",
+	"ProcSleep",
+	"SyncRep",
+	/* Timeout */
+	"BaseBackupThrottle",
+	"PgSleep",
+	"RecoveryApplyDelay"
+};
+
 #ifndef WIN32
 /* Are we currently in WaitLatch? The signal handler would like to know. */
 static volatile sig_atomic_t waiting = false;
@@ -297,9 +342,11 @@ DisownLatch(volatile Latch *latch)
  * we return all of them in one call, but we will return at least one.
  */
 int
-WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
+WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+		  uint32 wait_event)
 {
-	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout);
+	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout,
+							 wait_event);
 }
 
 /*
@@ -316,7 +363,7 @@ WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
  */
 int
 WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
-				  long timeout)
+				  long timeout, uint32 wait_event)
 {
 	int			ret = 0;
 	int			rc;
@@ -344,7 +391,7 @@ WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
 		AddWaitEventToSet(set, ev, sock, NULL, NULL);
 	}
 
-	rc = WaitEventSetWait(set, timeout, &event, 1);
+	rc = WaitEventSetWait(set, timeout, &event, 1, wait_event);
 
 	if (rc == 0)
 		ret |= WL_TIMEOUT;
@@ -863,7 +910,8 @@ WaitEventAdjustWin32(WaitEventSet *set, WaitEvent *event)
  */
 int
 WaitEventSetWait(WaitEventSet *set, long timeout,
-				 WaitEvent *occurred_events, int nevents)
+				 WaitEvent *occurred_events, int nevents,
+				 uint32 wait_event)
 {
 	int			returned_events = 0;
 	instr_time	start_time;
@@ -872,6 +920,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 
 	Assert(nevents > 0);
 
+	pgstat_report_wait_start(wait_event);
+
 	/*
 	 * Initialize timeout if requested.  We must record the current time so
 	 * that we can determine the remaining timeout if interrupted.
@@ -960,6 +1010,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 	waiting = false;
 #endif
 
+	pgstat_report_wait_end();
+
 	return returned_events;
 }
 
@@ -1491,6 +1543,22 @@ WaitEventSetWaitBlock(WaitEventSet *set, int cur_timeout,
 }
 #endif
 
+
+/*
+ * Return an event name for a WaitEventSet event depending on the ID
+ * provided by caller, ID used for the statistics collector.
+ */
+const char *
+GetWaitEventIdentifier(uint16 eventId)
+{
+	StaticAssertStmt(lengthof(WaitEventNames) == WAIT_EVENT_LAST_TYPE + 1,
+					 "WaitEventEntries must match WaitEventIdentifiers");
+	if (eventId > WAIT_EVENT_LAST_TYPE)
+		return "???";
+	return WaitEventNames[eventId];
+}
+
+
 /*
  * SetLatch uses SIGUSR1 to wake up the process waiting on the latch.
  *
diff --git a/src/backend/storage/ipc/shm_mq.c b/src/backend/storage/ipc/shm_mq.c
index 5b32782..4eea77d 100644
--- a/src/backend/storage/ipc/shm_mq.c
+++ b/src/backend/storage/ipc/shm_mq.c
@@ -19,6 +19,7 @@
 #include "postgres.h"
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/bgworker.h"
 #include "storage/procsignal.h"
 #include "storage/shm_mq.h"
@@ -894,7 +895,8 @@ shm_mq_send_bytes(shm_mq_handle *mqh, Size nbytes, const void *data,
 			 * at top of loop, because setting an already-set latch is much
 			 * cheaper than setting one that has been reset.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0,
+					  pgstat_make_wait_event(WAIT_IPC, WAIT_EVENT_MQ_SEND));
 
 			/* Reset the latch so we don't spin. */
 			ResetLatch(MyLatch);
@@ -991,7 +993,8 @@ shm_mq_receive_bytes(shm_mq *mq, Size bytes_needed, bool nowait,
 		 * loop, because setting an already-set latch is much cheaper than
 		 * setting one that has been reset.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0,
+				  pgstat_make_wait_event(WAIT_IPC, WAIT_EVENT_MQ_RECEIVE));
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
@@ -1090,7 +1093,8 @@ shm_mq_wait_internal(volatile shm_mq *mq, PGPROC *volatile * ptr,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0,
+				  pgstat_make_wait_event(WAIT_IPC, WAIT_EVENT_MQ_INTERNAL));
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/backend/storage/ipc/standby.c b/src/backend/storage/ipc/standby.c
index 547f1a8..bf0efef 100644
--- a/src/backend/storage/ipc/standby.c
+++ b/src/backend/storage/ipc/standby.c
@@ -356,7 +356,7 @@ ResolveRecoveryConflictWithDatabase(Oid dbid)
  * will be detected by the deadlock detector within the ordinary backend.
  */
 void
-ResolveRecoveryConflictWithLock(LOCKTAG locktag)
+ResolveRecoveryConflictWithLock(LOCKTAG locktag, uint32 wait_event)
 {
 	TimestampTz ltime;
 
@@ -389,7 +389,7 @@ ResolveRecoveryConflictWithLock(LOCKTAG locktag)
 	}
 
 	/* Wait to be signaled by the release of the Relation Lock */
-	ProcWaitForSignal();
+	ProcWaitForSignal(wait_event);
 
 	/*
 	 * Clear any timeout requests established above.  We assume here that the
@@ -428,7 +428,7 @@ ResolveRecoveryConflictWithLock(LOCKTAG locktag)
  * at least deadlock_timeout.
  */
 void
-ResolveRecoveryConflictWithBufferPin(void)
+ResolveRecoveryConflictWithBufferPin(uint32 wait_event)
 {
 	TimestampTz ltime;
 
@@ -469,7 +469,7 @@ ResolveRecoveryConflictWithBufferPin(void)
 	}
 
 	/* Wait to be signaled by UnpinBuffer() */
-	ProcWaitForSignal();
+	ProcWaitForSignal(wait_event);
 
 	/*
 	 * Clear any timeout requests established above.  We assume here that the
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index dba3809..8fa0b1f 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -1659,6 +1659,7 @@ WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
 	LOCKMETHODID lockmethodid = LOCALLOCK_LOCKMETHOD(*locallock);
 	LockMethod	lockMethodTable = LockMethods[lockmethodid];
 	char	   *volatile new_status = NULL;
+	uint32		wait_event;
 
 	LOCK_PRINT("WaitOnLock: sleeping on lock",
 			   locallock->lock, locallock->tag.mode);
@@ -1676,7 +1677,9 @@ WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
 		set_ps_display(new_status, false);
 		new_status[len] = '\0'; /* truncate off " waiting" */
 	}
-	pgstat_report_wait_start(WAIT_LOCK, locallock->tag.lock.locktag_type);
+
+	wait_event = pgstat_make_wait_event(WAIT_LOCK,
+										locallock->tag.lock.locktag_type);
 
 	awaitedLock = locallock;
 	awaitedOwner = owner;
@@ -1700,7 +1703,7 @@ WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
 	 */
 	PG_TRY();
 	{
-		if (ProcSleep(locallock, lockMethodTable) != STATUS_OK)
+		if (ProcSleep(locallock, lockMethodTable, wait_event) != STATUS_OK)
 		{
 			/*
 			 * We failed as a result of a deadlock, see CheckDeadLock(). Quit
@@ -1724,7 +1727,6 @@ WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
 		/* In this path, awaitedLock remains set until LockErrorCleanup */
 
 		/* Report change to non-waiting status */
-		pgstat_report_wait_end();
 		if (update_process_title)
 		{
 			set_ps_display(new_status, false);
@@ -1739,7 +1741,6 @@ WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
 	awaitedLock = NULL;
 
 	/* Report change to non-waiting status */
-	pgstat_report_wait_end();
 	if (update_process_title)
 	{
 		set_ps_display(new_status, false);
diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c
index 9d08de7..cc7bef9 100644
--- a/src/backend/storage/lmgr/lwlock.c
+++ b/src/backend/storage/lmgr/lwlock.c
@@ -730,11 +730,16 @@ static inline void
 LWLockReportWaitStart(LWLock *lock)
 {
 	int			lockId = T_ID(lock);
+	uint32		wait_event;
 
 	if (lock->tranche == 0)
-		pgstat_report_wait_start(WAIT_LWLOCK_NAMED, (uint16) lockId);
+		wait_event = pgstat_make_wait_event(WAIT_LWLOCK_NAMED,
+											(uint16) lockId);
 	else
-		pgstat_report_wait_start(WAIT_LWLOCK_TRANCHE, lock->tranche);
+		wait_event = pgstat_make_wait_event(WAIT_LWLOCK_TRANCHE,
+											lock->tranche);
+
+	pgstat_report_wait_start(wait_event);
 }
 
 /*
diff --git a/src/backend/storage/lmgr/predicate.c b/src/backend/storage/lmgr/predicate.c
index 4064b20..f292834 100644
--- a/src/backend/storage/lmgr/predicate.c
+++ b/src/backend/storage/lmgr/predicate.c
@@ -1518,7 +1518,7 @@ GetSafeSnapshot(Snapshot origSnapshot)
 				 SxactIsROUnsafe(MySerializableXact)))
 		{
 			LWLockRelease(SerializableXactHashLock);
-			ProcWaitForSignal();
+			ProcWaitForSignal(0);
 			LWLockAcquire(SerializableXactHashLock, LW_EXCLUSIVE);
 		}
 		MySerializableXact->flags &= ~SXACT_FLAG_DEFERRABLE_WAITING;
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 33e7023..7353094 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -39,6 +39,7 @@
 #include "access/twophase.h"
 #include "access/xact.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/autovacuum.h"
 #include "replication/slot.h"
 #include "replication/syncrep.h"
@@ -977,6 +978,9 @@ ProcQueueInit(PROC_QUEUE *queue)
  * The lock table's partition lock must be held at entry, and will be held
  * at exit.
  *
+ * wait_event tracks what is the wait event caller is expecting to wait for.
+ * If set to 0 the default wait event for ProcSleep() is used.
+ *
  * Result: STATUS_OK if we acquired the lock, STATUS_ERROR if not (deadlock).
  *
  * ASSUME: that no one will fiddle with the queue until after
@@ -985,7 +989,8 @@ ProcQueueInit(PROC_QUEUE *queue)
  * NOTES: The process queue is now a priority queue for locking.
  */
 int
-ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
+ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable,
+		  uint32 wait_event)
 {
 	LOCKMODE	lockmode = locallock->tag.mode;
 	LOCK	   *lock = locallock->lock;
@@ -1023,6 +1028,14 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
 	}
 
 	/*
+	 * If caller did not provide the wait event it is expected to look for,
+	 * set up a default one.
+	 */
+	if (wait_event == 0)
+		wait_event = pgstat_make_wait_event(WAIT_ACTIVITY,
+											WAIT_EVENT_PROC_SLEEP);
+
+	/*
 	 * Determine where to add myself in the wait queue.
 	 *
 	 * Normally I should go at the end of the queue.  However, if I already
@@ -1208,11 +1221,11 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
 		if (InHotStandby)
 		{
 			/* Set a timer and wait for that or for the Lock to be granted */
-			ResolveRecoveryConflictWithLock(locallock->tag.lock);
+			ResolveRecoveryConflictWithLock(locallock->tag.lock, wait_event);
 		}
 		else
 		{
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, wait_event);
 			ResetLatch(MyLatch);
 			/* check for deadlocks first, as that's probably log-worthy */
 			if (got_deadlock_timeout)
@@ -1717,14 +1730,24 @@ CheckDeadLockAlert(void)
 /*
  * ProcWaitForSignal - wait for a signal from another backend.
  *
+ * wait_event tracks what is the wait event caller is expecting to wait for.
+ * If set to 0 the default wait event for ProcWaitForSignal() is used.
+ *
  * As this uses the generic process latch the caller has to be robust against
  * unrelated wakeups: Always check that the desired state has occurred, and
  * wait again if not.
  */
 void
-ProcWaitForSignal(void)
+ProcWaitForSignal(uint32 wait_event)
 {
-	WaitLatch(MyLatch, WL_LATCH_SET, 0);
+	/*
+	 * If caller did not provide the wait event it is expected to look for,
+	 * set up a default one.
+	 */
+	if (wait_event == 0)
+		pgstat_make_wait_event(WAIT_IPC, WAIT_EVENT_PROC_SIGNAL);
+
+	WaitLatch(MyLatch, WL_LATCH_SET, 0, wait_event);
 	ResetLatch(MyLatch);
 	CHECK_FOR_INTERRUPTS();
 }
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 5e705e9..880e72c 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -30,6 +30,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "parser/scansup.h"
+#include "pgstat.h"
 #include "postmaster/syslogger.h"
 #include "rewrite/rewriteHandler.h"
 #include "storage/fd.h"
@@ -560,7 +561,9 @@ pg_sleep(PG_FUNCTION_ARGS)
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | WL_TIMEOUT,
-						 delay_ms);
+						 delay_ms,
+						 pgstat_make_wait_event(WAIT_TIMEOUT,
+												WAIT_EVENT_PG_SLEEP));
 		ResetLatch(MyLatch);
 	}
 
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0c98c59..bc8081b 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -721,8 +721,13 @@ typedef enum WaitClass
 	WAIT_LWLOCK_NAMED,
 	WAIT_LWLOCK_TRANCHE,
 	WAIT_LOCK,
-	WAIT_BUFFER_PIN
-}	WaitClass;
+	WAIT_BUFFER_PIN,
+	WAIT_ACTIVITY,
+	WAIT_CLIENT,
+	WAIT_EXTENSION,
+	WAIT_IPC,
+	WAIT_TIMEOUT
+} WaitClass;
 
 
 /* ----------
@@ -1018,23 +1023,18 @@ extern void pgstat_initstats(Relation rel);
  * ----------
  */
 static inline void
-pgstat_report_wait_start(uint8 classId, uint16 eventId)
+pgstat_report_wait_start(uint32 wait_event)
 {
 	volatile PGPROC *proc = MyProc;
-	uint32		wait_event_val;
 
 	if (!pgstat_track_activities || !proc)
 		return;
 
-	wait_event_val = classId;
-	wait_event_val <<= 24;
-	wait_event_val |= eventId;
-
 	/*
 	 * Since this is a four-byte field which is always read and written as
 	 * four-bytes, updates are atomic.
 	 */
-	proc->wait_event_info = wait_event_val;
+	proc->wait_event_info = wait_event;
 }
 
 /* ----------
@@ -1061,6 +1061,16 @@ pgstat_report_wait_end(void)
 	proc->wait_event_info = 0;
 }
 
+/* ----------
+ * pgstat_make_wait_event()
+ *
+ *	Build a value to be used for report in pgstat_report_wait_start().
+ *	This respects the format per the description above.
+ * ----------
+ */
+#define pgstat_make_wait_event(classId, eventId)					\
+	((classId << 24) | eventId)
+
 /* nontransactional event counts are simple enough to inline */
 
 #define pgstat_count_heap_scan(rel)									\
diff --git a/src/include/storage/latch.h b/src/include/storage/latch.h
index 5179ecc..293ea99 100644
--- a/src/include/storage/latch.h
+++ b/src/include/storage/latch.h
@@ -135,6 +135,70 @@ typedef struct WaitEvent
 	void	   *user_data;		/* pointer provided in AddWaitEventToSet */
 } WaitEvent;
 
+/*
+ * List of WaitEventSet identifiers used when reporting activity to
+ * statistics collector. Up to 256 different WaitEventIdentifier can be
+ * handled. Those are classified by category first, and then by
+ * alphabetical order. Events are classified into sub-categories following
+ * some basic hierarchy rules:
+ * - "Activity" for main loops of processes waiting for an event.
+ * - "Client" for a socket awaited when a user is connected.
+ * - "IPC", similarly to "Client", for a socket awaited from another
+ *   server process.
+ * - "Timeout", for a timeout waiting to expire.
+ * - "Extension", to let extension modules a way to define a custom wait
+ *   point.
+ */
+typedef enum WaitEventIdentifier
+{
+	/* Activity */
+	WAIT_EVENT_ARCHIVER_MAIN,
+	WAIT_EVENT_AUTOVACUUM_MAIN,
+	WAIT_EVENT_BGWRITER_HIBERNATE,
+	WAIT_EVENT_BGWRITER_MAIN,
+	WAIT_EVENT_CHECKPOINTER_MAIN,
+	WAIT_EVENT_PGSTAT_MAIN,
+	WAIT_EVENT_RECOVERY_WAL_ALL,
+	WAIT_EVENT_RECOVERY_WAL_STREAM,
+	WAIT_EVENT_SYSLOGGER_MAIN,
+	WAIT_EVENT_WAL_RECEIVER_MAIN,
+	WAIT_EVENT_WAL_SENDER_MAIN,
+	WAIT_EVENT_WAL_WRITER_MAIN,
+	/* Client */
+	WAIT_EVENT_SECURE_READ,
+	WAIT_EVENT_SECURE_WRITE,
+	WAIT_EVENT_SSL_OPEN_SERVER,
+	WAIT_EVENT_WAL_RECEIVER_WAIT_START,
+	WAIT_EVENT_WAL_SENDER_WAIT_WAL,
+	WAIT_EVENT_WAL_SENDER_WRITE_DATA,
+	/* Extension */
+	WAIT_EVENT_EXTENSION,
+	/* IPC */
+	WAIT_EVENT_BGWORKER_SHUTDOWN,
+	WAIT_EVENT_BGWORKER_STARTUP,
+	WAIT_EVENT_EXECUTE_GATHER,
+	WAIT_EVENT_MQ_INTERNAL,
+	WAIT_EVENT_MQ_PUT_MESSAGE,
+	WAIT_EVENT_MQ_RECEIVE,
+	WAIT_EVENT_MQ_SEND,
+	WAIT_EVENT_PARALLEL_FINISH,
+	WAIT_EVENT_PROC_SIGNAL,
+	WAIT_EVENT_PROC_SLEEP,
+	WAIT_EVENT_SYNC_REP,
+	/* Timeout */
+	WAIT_EVENT_BASE_BACKUP_THROTTLE,
+	WAIT_EVENT_PG_SLEEP,
+	WAIT_EVENT_RECOVERY_APPLY_DELAY
+} WaitEventIdentifier;
+
+#define WAIT_EVENT_LAST_TYPE WAIT_EVENT_RECOVERY_APPLY_DELAY
+
+/*
+ * The information details about each WaitEventIdentifier listed above
+ * are specified by an array of name-pair values.
+ */
+extern const char *const WaitEventName[];
+
 /* forward declaration to avoid exposing latch.c implementation details */
 typedef struct WaitEventSet WaitEventSet;
 
@@ -155,10 +219,14 @@ extern int AddWaitEventToSet(WaitEventSet *set, uint32 events, pgsocket fd,
 				  Latch *latch, void *user_data);
 extern void ModifyWaitEvent(WaitEventSet *set, int pos, uint32 events, Latch *latch);
 
-extern int	WaitEventSetWait(WaitEventSet *set, long timeout, WaitEvent *occurred_events, int nevents);
-extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout);
+extern int	WaitEventSetWait(WaitEventSet *set, long timeout,
+				  WaitEvent *occurred_events, int nevents,
+				  uint32 wait_event);
+extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+				  uint32 wait_event);
 extern int WaitLatchOrSocket(volatile Latch *latch, int wakeEvents,
-				  pgsocket sock, long timeout);
+				  pgsocket sock, long timeout, uint32 wait_event);
+extern const char *GetWaitEventIdentifier(uint16 eventId);
 
 /*
  * Unix implementation uses SIGUSR1 for inter-process signaling.
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index f576f05..65212ac 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -284,14 +284,15 @@ extern bool HaveNFreeProcs(int n);
 extern void ProcReleaseLocks(bool isCommit);
 
 extern void ProcQueueInit(PROC_QUEUE *queue);
-extern int	ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable);
+extern int	ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable,
+					  uint32 wait_event);
 extern PGPROC *ProcWakeup(PGPROC *proc, int waitStatus);
 extern void ProcLockWakeup(LockMethod lockMethodTable, LOCK *lock);
 extern void CheckDeadLockAlert(void);
 extern bool IsWaitingForLock(void);
 extern void LockErrorCleanup(void);
 
-extern void ProcWaitForSignal(void);
+extern void ProcWaitForSignal(uint32 wait_event);
 extern void ProcSendSignal(int pid);
 
 extern void BecomeLockGroupLeader(void);
diff --git a/src/include/storage/standby.h b/src/include/storage/standby.h
index dcebf72..3c189c2 100644
--- a/src/include/storage/standby.h
+++ b/src/include/storage/standby.h
@@ -32,8 +32,9 @@ extern void ResolveRecoveryConflictWithSnapshot(TransactionId latestRemovedXid,
 extern void ResolveRecoveryConflictWithTablespace(Oid tsid);
 extern void ResolveRecoveryConflictWithDatabase(Oid dbid);
 
-extern void ResolveRecoveryConflictWithLock(LOCKTAG locktag);
-extern void ResolveRecoveryConflictWithBufferPin(void);
+extern void ResolveRecoveryConflictWithLock(LOCKTAG locktag,
+											uint32 wait_event);
+extern void ResolveRecoveryConflictWithBufferPin(uint32 wait_event);
 extern void CheckRecoveryConflictDeadlock(void);
 extern void StandbyDeadLockHandler(void);
 extern void StandbyTimeoutHandler(void);
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 143df4e..64f9b8b 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -16,6 +16,7 @@
 #include "postgres.h"
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/bgworker.h"
 #include "storage/procsignal.h"
 #include "storage/shm_toc.h"
@@ -279,7 +280,9 @@ wait_for_workers_to_become_ready(worker_state *wstate,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0,
+				  pgstat_make_wait_event(WAIT_EXTENSION,
+										 WAIT_EVENT_EXTENSION));
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/test/modules/test_shm_mq/test.c b/src/test/modules/test_shm_mq/test.c
index dd34bc7..9b3e80e 100644
--- a/src/test/modules/test_shm_mq/test.c
+++ b/src/test/modules/test_shm_mq/test.c
@@ -15,6 +15,7 @@
 
 #include "fmgr.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 
 #include "test_shm_mq.h"
 
@@ -230,7 +231,9 @@ test_shm_mq_pipelined(PG_FUNCTION_ARGS)
 			 * have read or written data and therefore there may now be work
 			 * for us to do.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0,
+					  pgstat_make_wait_event(WAIT_EXTENSION,
+											 WAIT_EVENT_EXTENSION));
 			ResetLatch(MyLatch);
 			CHECK_FOR_INTERRUPTS();
 		}
diff --git a/src/test/modules/worker_spi/worker_spi.c b/src/test/modules/worker_spi/worker_spi.c
index 7c9a3eb..d738f21 100644
--- a/src/test/modules/worker_spi/worker_spi.c
+++ b/src/test/modules/worker_spi/worker_spi.c
@@ -227,7 +227,9 @@ worker_spi_main(Datum main_arg)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   worker_spi_naptime * 1000L);
+					   worker_spi_naptime * 1000L,
+					   pgstat_make_wait_event(WAIT_EXTENSION,
+											  WAIT_EVENT_EXTENSION));
 		ResetLatch(MyLatch);
 
 		/* emergency bailout if postmaster has died */

diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 8ca1c1c..ffa72b8 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -17,6 +17,7 @@
 #include "access/xact.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "storage/latch.h"
 #include "utils/hsearch.h"
 #include "utils/memutils.h"
@@ -491,12 +492,18 @@ pgfdw_get_result(PGconn *conn, const char *query)
 		while (PQisBusy(conn))
 		{
 			int			wc;
+			uint32		pgstat_desc;
+
+			/* Define event to wait for */
+			pgstat_desc = pgstat_make_wait_desc(WAIT_EXTENSION,
+												WAIT_EVENT_EXTENSION);
 
 			/* Sleep until there's something to do */
 			wc = WaitLatchOrSocket(MyLatch,
 								   WL_LATCH_SET | WL_SOCKET_READABLE,
 								   PQsocket(conn),
-								   -1L);
+								   -1L,
+								   pgstat_desc);
 			ResetLatch(MyLatch);
 
 			CHECK_FOR_INTERRUPTS();
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index f400785..bb975c1 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -679,6 +679,42 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
           buffer in question.
          </para>
         </listitem>
+        <listitem>
+         <para>
+          <literal>Activity</>: The server process is idle.  This is used by
+          system processes waiting for activity in their main processing loop.
+          <literal>wait_event</> will identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Extension</>: The server process is waiting for activity
+          in an extension module.  This category is useful for modules to
+          track custom waiting points.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Client</>: The server process is waiting for some activity
+          on a socket from user applications, and that the server expects
+          something to happen that is independent from its internal processes.
+          <literal>wait_event</> will identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>IPC</>: The server process is waiting for some activity
+          from another process in the server.  <literal>wait_event</> will
+          identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Timeout</>: The server process is waiting for a timeout
+          to expire.  <literal>wait_event</> will identify the specific wait
+          point.
+         </para>
+        </listitem>
        </itemizedlist>
       </entry>
      </row>
@@ -1085,6 +1121,143 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
          <entry><literal>BufferPin</></entry>
          <entry>Waiting to acquire a pin on a buffer.</entry>
         </row>
+        <row>
+         <entry morerows="11"><literal>Activity</></entry>
+         <entry><literal>ArchiverMain</></entry>
+         <entry>Waiting in main loop of the archiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>AutoVacuumMain</></entry>
+         <entry>Waiting in main loop of autovacuum launcher process.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterHibernate</></entry>
+         <entry>Waiting in background writer process, hibernating.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterMain</></entry>
+         <entry>Waiting in main loop of background writer process background worker.</entry>
+        </row>
+        <row>
+         <entry><literal>CheckpointerMain</></entry>
+         <entry>Waiting in main loop of checkpointer process.</entry>
+        </row>
+        <row>
+         <entry><literal>PgStatMain</></entry>
+         <entry>Waiting in main loop of the statistics collector process.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalAll</></entry>
+         <entry>Waiting for WAL from any kind of source (local, archive or stream) at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalStream</></entry>
+         <entry>Waiting for WAL from a stream at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>SysLoggerMain</></entry>
+         <entry>Waiting in main loop of syslogger process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverMain</></entry>
+         <entry>Waiting in main loop of WAL receiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderMain</></entry>
+         <entry>Waiting in main loop of WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalWriterMain</></entry>
+         <entry>Waiting in main loop of WAL writer process.</entry>
+        </row>
+        <row>
+         <entry morerows="5"><literal>Client</></entry>
+         <entry><literal>SecureRead</></entry>
+         <entry>Waiting to read data from a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SecureWrite</></entry>
+         <entry>Waiting to write data to a secure connection.</entry>
+        </row>
+        <row>
+         <entry><literal>SSLOpenServer</></entry>
+         <entry>Waiting for SSL while attempting connection.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverWaitStart</></entry>
+         <entry>Waiting for startup process to send initial data for streaming replication.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWaitForWAL</></entry>
+         <entry>Waiting for WAL to be flushed in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWriteData</></entry>
+         <entry>Waiting for any activity when processing replies from WAL receiver in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>Extension</></entry>
+         <entry><literal>Extension</></entry>
+         <entry>Waiting in the code path of an extension, should be used by custom plugins and modules</entry>
+        </row>
+        <row>
+         <entry morerows="10"><literal>IPC</></entry>
+         <entry><literal>BgWorkerShutdown</></entry>
+         <entry>Waiting for background worker to shut down.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWorkerStartup</></entry>
+         <entry>Waiting for background worker to start up.</entry>
+        </row>
+        <row>
+         <entry><literal>ExecuteGather</></entry>
+         <entry>Waiting for activity from child process when executing <literal>Gather</> node.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueInternal</></entry>
+         <entry>Waiting for other process to be attached in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueuePutMessage</></entry>
+         <entry>Waiting to put new message in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueReceive</></entry>
+         <entry>Waiting to receive bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueSend</></entry>
+         <entry>Waiting to send bytes in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>ParallelFinish</></entry>
+         <entry>Waiting for parallel workers to finish computing.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSignal</></entry>
+         <entry>Waiting for signal from another backend.</entry>
+        </row>
+        <row>
+         <entry><literal>ProcSleep</></entry>
+         <entry>Waiting for a specific lock.</entry>
+        </row>
+        <row>
+         <entry><literal>SyncRep</></entry>
+         <entry>Waiting for WAL commit during synchronous replication.</entry>
+        </row>
+        <row>
+         <entry morerows="2"><literal>Timeout</></entry>
+         <entry><literal>BaseBackupThrottle</></entry>
+         <entry>Waiting during base backup when throttling activity.</entry>
+        </row>
+        <row>
+         <entry><literal>PgSleep</></entry>
+         <entry>Waiting in process that called <function>pg_sleep</>.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryApplyDelay</></entry>
+         <entry>Waiting to apply WAL at recovery because it is delayed.</entry>
+        </row>
       </tbody>
      </tgroup>
     </table>
diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c
index cde0ed3..dd0eb76 100644
--- a/src/backend/access/transam/parallel.c
+++ b/src/backend/access/transam/parallel.c
@@ -23,6 +23,7 @@
 #include "libpq/pqformat.h"
 #include "libpq/pqmq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "optimizer/planmain.h"
 #include "storage/ipc.h"
 #include "storage/sinval.h"
@@ -540,7 +541,9 @@ WaitForParallelWorkersToFinish(ParallelContext *pcxt)
 		if (!anyone_alive)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1,
+				  pgstat_make_wait_desc(WAIT_IPC,
+										WAIT_EVENT_PARALLEL_FINISH));
 		ResetLatch(&MyProc->procLatch);
 	}
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index c1b9a97..8e7626f 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5827,7 +5827,9 @@ recoveryApplyDelay(XLogReaderState *record)
 
 		WaitLatch(&XLogCtl->recoveryWakeupLatch,
 				  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-				  secs * 1000L + microsecs / 1000);
+				  secs * 1000L + microsecs / 1000,
+				  pgstat_make_wait_desc(WAIT_TIMEOUT,
+										WAIT_EVENT_RECOVERY_APPLY_DELAY));
 	}
 	return true;
 }
@@ -11380,14 +11382,19 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 						long		secs,
 									wait_time;
 						int			usecs;
+						uint32		pgstat_desc;
 
 						TimestampDifference(last_fail_time, now, &secs, &usecs);
 						wait_time = wal_retrieve_retry_interval -
 							(secs * 1000 + usecs / 1000);
+						pgstat_desc = pgstat_make_wait_desc(WAIT_ACTIVITY,
+											WAIT_EVENT_RECOVERY_APPLY_DELAY);
 
 						WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								  wait_time);
+							 wait_time,
+							 pgstat_desc);
+
 						ResetLatch(&XLogCtl->recoveryWakeupLatch);
 						now = GetCurrentTimestamp();
 					}
@@ -11550,7 +11557,9 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					 */
 					WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							  5000L);
+							  5000L,
+							  pgstat_make_wait_desc(WAIT_ACTIVITY,
+												WAIT_EVENT_RECOVERY_WAL_ALL));
 					ResetLatch(&XLogCtl->recoveryWakeupLatch);
 					break;
 				}
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 438d1b2..af2f0f1 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -38,6 +38,7 @@
 #include "executor/nodeSubplan.h"
 #include "executor/tqueue.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "utils/memutils.h"
 #include "utils/rel.h"
 
@@ -387,7 +388,9 @@ gather_readnext(GatherState *gatherstate)
 				return NULL;
 
 			/* Nothing to do except wait for developments. */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0,
+					  pgstat_make_wait_desc(WAIT_IPC,
+											WAIT_EVENT_EXECUTE_GATHER));
 			ResetLatch(MyLatch);
 			nvisited = 0;
 		}
diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
index fedb02c..4dfe969 100644
--- a/src/backend/libpq/be-secure-openssl.c
+++ b/src/backend/libpq/be-secure-openssl.c
@@ -60,6 +60,7 @@
 
 #include "libpq/libpq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "storage/latch.h"
 #include "tcop/tcopprot.h"
 #include "utils/memutils.h"
@@ -419,7 +420,9 @@ aloop:
 				else
 					waitfor = WL_SOCKET_WRITEABLE;
 
-				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0);
+				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0,
+						  pgstat_make_wait_desc(WAIT_CLIENT,
+												WAIT_EVENT_SSL_OPEN_SERVER));
 				goto aloop;
 			case SSL_ERROR_SYSCALL:
 				if (r < 0)
diff --git a/src/backend/libpq/be-secure.c b/src/backend/libpq/be-secure.c
index cdd07d5..323283e 100644
--- a/src/backend/libpq/be-secure.c
+++ b/src/backend/libpq/be-secure.c
@@ -33,6 +33,7 @@
 
 #include "libpq/libpq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "tcop/tcopprot.h"
 #include "utils/memutils.h"
 #include "storage/ipc.h"
@@ -146,7 +147,9 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 pgstat_make_wait_desc(WAIT_CLIENT,
+											   WAIT_EVENT_SECURE_READ));
 
 		/*
 		 * If the postmaster has died, it's not safe to continue running,
@@ -247,7 +250,9 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 pgstat_make_wait_desc(WAIT_CLIENT,
+											   WAIT_EVENT_SECURE_WRITE));
 
 		/* See comments in secure_read. */
 		if (event.events & WL_POSTMASTER_DEATH)
diff --git a/src/backend/libpq/pqmq.c b/src/backend/libpq/pqmq.c
index bfe66c6..3b697e6 100644
--- a/src/backend/libpq/pqmq.c
+++ b/src/backend/libpq/pqmq.c
@@ -17,6 +17,7 @@
 #include "libpq/pqformat.h"
 #include "libpq/pqmq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "tcop/tcopprot.h"
 #include "utils/builtins.h"
 
@@ -171,7 +172,9 @@ mq_putmessage(char msgtype, const char *s, size_t len)
 		if (result != SHM_MQ_WOULD_BLOCK)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0,
+				  pgstat_make_wait_desc(WAIT_IPC,
+										WAIT_EVENT_MQ_PUT_MESSAGE));
 		ResetLatch(&MyProc->procLatch);
 		CHECK_FOR_INTERRUPTS();
 	}
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 1a92ca1..7f0ad32 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -598,7 +598,9 @@ AutoVacLauncherMain(int argc, char *argv[])
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L));
+					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L),
+					   pgstat_make_wait_desc(WAIT_ACTIVITY,
+											 WAIT_EVENT_AUTOVACUUM_MAIN));
 
 		ResetLatch(MyLatch);
 
diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c
index 699c934..3f2457a 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -16,6 +16,7 @@
 
 #include "miscadmin.h"
 #include "libpq/pqsignal.h"
+#include "pgstat.h"
 #include "postmaster/bgworker_internals.h"
 #include "postmaster/postmaster.h"
 #include "storage/barrier.h"
@@ -969,7 +970,9 @@ WaitForBackgroundWorkerStartup(BackgroundWorkerHandle *handle, pid_t *pidp)
 			break;
 
 		rc = WaitLatch(MyLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   pgstat_make_wait_desc(WAIT_IPC,
+											 WAIT_EVENT_BGWORKER_STARTUP));
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
@@ -1008,7 +1011,9 @@ WaitForBackgroundWorkerShutdown(BackgroundWorkerHandle *handle)
 			break;
 
 		rc = WaitLatch(&MyProc->procLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   pgstat_make_wait_desc(WAIT_IPC,
+											 WAIT_EVENT_BGWORKER_SHUTDOWN));
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index 1002034..1326d17 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -345,7 +345,9 @@ BackgroundWriterMain(void)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   BgWriterDelay /* ms */ );
+					   BgWriterDelay /* ms */,
+					   pgstat_make_wait_desc(WAIT_ACTIVITY,
+											 WAIT_EVENT_BGWRITER_MAIN));
 
 		/*
 		 * If no latch event and BgBufferSync says nothing's happening, extend
@@ -371,8 +373,10 @@ BackgroundWriterMain(void)
 			StrategyNotifyBgWriter(MyProc->pgprocno);
 			/* Sleep ... */
 			rc = WaitLatch(MyLatch,
-						   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-						   BgWriterDelay * HIBERNATE_FACTOR);
+				   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
+				   BgWriterDelay * HIBERNATE_FACTOR,
+				   pgstat_make_wait_desc(WAIT_ACTIVITY,
+										 WAIT_EVENT_BGWRITER_HIBERNATE));
 			/* Reset the notification request in case we timed out */
 			StrategyNotifyBgWriter(-1);
 		}
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index d702a48..9d3121d 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -556,7 +556,9 @@ CheckpointerMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout * 1000L /* convert to ms */ );
+					   cur_timeout * 1000L /* convert to ms */,
+					   pgstat_make_wait_desc(WAIT_ACTIVITY,
+											 WAIT_EVENT_CHECKPOINTER_MAIN));
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 1aa6466..e54e30a 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -390,7 +390,9 @@ pgarch_MainLoop(void)
 
 				rc = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							   timeout * 1000L);
+							 timeout * 1000L,
+							 pgstat_make_wait_desc(WAIT_ACTIVITY,
+												   WAIT_EVENT_ARCHIVER_MAIN));
 				if (rc & WL_TIMEOUT)
 					wakened = true;
 			}
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 96578dc..fef1aab 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -3155,6 +3155,18 @@ pgstat_get_wait_event_type(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_type = "BufferPin";
 			break;
+		case WAIT_ACTIVITY:
+			event_type = "Activity";
+			break;
+		case WAIT_CLIENT:
+			event_type = "Client";
+			break;
+		case WAIT_IPC:
+			event_type = "IPC";
+			break;
+		case WAIT_TIMEOUT:
+			event_type = "Timeout";
+			break;
 		default:
 			event_type = "???";
 			break;
@@ -3196,6 +3208,13 @@ pgstat_get_wait_event(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_name = "BufferPin";
 			break;
+		case WAIT_ACTIVITY:
+		case WAIT_CLIENT:
+		case WAIT_EXTENSION:
+		case WAIT_IPC:
+		case WAIT_TIMEOUT:
+			event_name = GetWaitEventIdentifier(eventId);
+			break;
 		default:
 			event_name = "unknown wait event";
 			break;
@@ -3684,8 +3703,9 @@ PgstatCollectorMain(int argc, char *argv[])
 #ifndef WIN32
 		wr = WaitLatchOrSocket(MyLatch,
 					 WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE,
-							   pgStatSock,
-							   -1L);
+					 pgStatSock, -1L,
+					 pgstat_make_wait_desc(WAIT_ACTIVITY,
+										   WAIT_EVENT_PGSTAT_MAIN));
 #else
 
 		/*
@@ -3700,8 +3720,10 @@ PgstatCollectorMain(int argc, char *argv[])
 		 */
 		wr = WaitLatchOrSocket(MyLatch,
 		WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE | WL_TIMEOUT,
-							   pgStatSock,
-							   2 * 1000L /* msec */ );
+					 pgStatSock,
+					 2 * 1000L /* msec */,
+					 pgstat_make_wait_desc(WAIT_ACTIVITY,
+										   WAIT_EVENT_PGSTAT_MAIN));
 #endif
 
 		/*
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index e7e488a..358d3ad 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -34,6 +34,7 @@
 #include "lib/stringinfo.h"
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "nodes/pg_list.h"
 #include "pgtime.h"
 #include "postmaster/fork_process.h"
@@ -424,7 +425,9 @@ SysLoggerMain(int argc, char *argv[])
 		rc = WaitLatchOrSocket(MyLatch,
 							   WL_LATCH_SET | WL_SOCKET_READABLE | cur_flags,
 							   syslogPipe[0],
-							   cur_timeout);
+							   cur_timeout,
+					   pgstat_make_wait_desc(WAIT_ACTIVITY,
+											 WAIT_EVENT_SYSLOGGER_MAIN));
 
 		if (rc & WL_SOCKET_READABLE)
 		{
@@ -475,7 +478,9 @@ SysLoggerMain(int argc, char *argv[])
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | cur_flags,
-						 cur_timeout);
+						 cur_timeout,
+						 pgstat_make_wait_desc(WAIT_ACTIVITY,
+											   WAIT_EVENT_SYSLOGGER_MAIN));
 
 		EnterCriticalSection(&sysloggerSection);
 #endif   /* WIN32 */
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index 11ec56a..a96c4be 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -290,7 +290,9 @@ WalWriterMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout);
+					   cur_timeout,
+					   pgstat_make_wait_desc(WAIT_ACTIVITY,
+											 WAIT_EVENT_WAL_WRITER_MAIN));
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index 1eabaef..ea6286e 100644
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -1363,8 +1363,10 @@ throttle(size_t increment)
 		 * the maximum time to sleep. Thus the cast to long is safe.
 		 */
 		wait_result = WaitLatch(MyLatch,
-							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								(long) (sleep / 1000));
+					WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
+					(long) (sleep / 1000),
+					pgstat_make_wait_desc(WAIT_TIMEOUT,
+										  WAIT_EVENT_BASE_BACKUP_THROTTLE));
 
 		if (wait_result & WL_LATCH_SET)
 			CHECK_FOR_INTERRUPTS();
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index b442d06..d6b8d92 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -61,6 +61,7 @@
 
 #include "access/xact.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "replication/syncrep.h"
 #include "replication/walsender.h"
 #include "replication/walsender_private.h"
@@ -258,7 +259,9 @@ SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
 		 * Wait on latch.  Any condition that should wake us up will set the
 		 * latch, so no need for timeout.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1);
+		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1,
+				  pgstat_make_wait_desc(WAIT_IPC,
+										WAIT_EVENT_SYNC_REP));
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 413ee3a..8715332 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -55,6 +55,7 @@
 #include "libpq/pqformat.h"
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "replication/walreceiver.h"
 #include "replication/walsender.h"
 #include "storage/ipc.h"
@@ -401,6 +402,7 @@ WalReceiverMain(void)
 				bool		endofwal = false;
 				pgsocket	wait_fd = PGINVALID_SOCKET;
 				int			rc;
+				uint32		pgstat_desc;
 
 				/*
 				 * Exit walreceiver if we're not in recovery. This should not
@@ -482,11 +484,15 @@ WalReceiverMain(void)
 				 * avoiding some system calls.
 				 */
 				Assert(wait_fd != PGINVALID_SOCKET);
+				pgstat_desc = pgstat_make_wait_desc(WAIT_ACTIVITY,
+										  WAIT_EVENT_WAL_RECEIVER_MAIN);
 				rc = WaitLatchOrSocket(&walrcv->latch,
 								   WL_POSTMASTER_DEATH | WL_SOCKET_READABLE |
 									   WL_TIMEOUT | WL_LATCH_SET,
 									   wait_fd,
-									   NAPTIME_PER_CYCLE);
+									   NAPTIME_PER_CYCLE,
+									   pgstat_desc);
+
 				if (rc & WL_LATCH_SET)
 				{
 					ResetLatch(&walrcv->latch);
@@ -685,7 +691,9 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 		}
 		SpinLockRelease(&walrcv->mutex);
 
-		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+				  pgstat_make_wait_desc(WAIT_CLIENT,
+										WAIT_EVENT_WAL_RECEIVER_WAIT_START));
 	}
 
 	if (update_process_title)
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index c7743da..573107f 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -1146,7 +1146,9 @@ WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid,
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  pgstat_make_wait_desc(WAIT_CLIENT,
+										 WAIT_EVENT_WAL_SENDER_WRITE_DATA));
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1272,7 +1274,9 @@ WalSndWaitForWal(XLogRecPtr loc)
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  pgstat_make_wait_desc(WAIT_CLIENT,
+										 WAIT_EVENT_WAL_SENDER_WAIT_WAL));
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1924,7 +1928,9 @@ WalSndLoop(WalSndSendDataCallback send_data)
 
 			/* Sleep until something happens or we time out */
 			WaitLatchOrSocket(MyLatch, wakeEvents,
-							  MyProcPort->sock, sleeptime);
+							  MyProcPort->sock, sleeptime,
+							  pgstat_make_wait_desc(WAIT_ACTIVITY,
+										 WAIT_EVENT_WAL_SENDER_MAIN));
 		}
 	}
 	return;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 90804a3..aaeb75c 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -3610,6 +3610,7 @@ LockBufferForCleanup(Buffer buffer)
 	for (;;)
 	{
 		uint32		buf_state;
+		uint32		pgstat_desc;
 
 		/* Try to acquire lock */
 		LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
@@ -3635,8 +3636,8 @@ LockBufferForCleanup(Buffer buffer)
 		UnlockBufHdr(bufHdr, buf_state);
 		LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
 
-		/* Report the wait */
-		pgstat_report_wait_start(WAIT_BUFFER_PIN, 0);
+		/* Define the event to wait for */
+		pgstat_desc = pgstat_make_wait_desc(WAIT_BUFFER_PIN, 0);
 
 		/* Wait to be signaled by UnpinBuffer() */
 		if (InHotStandby)
@@ -3644,14 +3645,12 @@ LockBufferForCleanup(Buffer buffer)
 			/* Publish the bufid that Startup process waits on */
 			SetStartupBufferPinWaitBufId(buffer - 1);
 			/* Set alarm and then wait to be signaled by UnpinBuffer() */
-			ResolveRecoveryConflictWithBufferPin();
+			ResolveRecoveryConflictWithBufferPin(pgstat_desc);
 			/* Reset the published bufid */
 			SetStartupBufferPinWaitBufId(-1);
 		}
 		else
-			ProcWaitForSignal();
-
-		pgstat_report_wait_end();
+			ProcWaitForSignal(pgstat_desc);
 
 		/*
 		 * Remove flag marking us as waiter. Normally this will not be set
diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c
index 9def8a1..c29cab2 100644
--- a/src/backend/storage/ipc/latch.c
+++ b/src/backend/storage/ipc/latch.c
@@ -55,6 +55,7 @@
 #endif
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "portability/instr_time.h"
 #include "postmaster/postmaster.h"
 #include "storage/barrier.h"
@@ -122,6 +123,50 @@ struct WaitEventSet
 #endif
 };
 
+/*
+ * This must match enum WaitEventIdentifier!
+ */
+const char *const WaitEventNames[] = {
+	/* Activity */
+	"ArchiverMain",
+	"AutoVacuumMain",
+	"BgWriterHibernate",
+	"BgWriterMain",
+	"CheckpointerMain",
+	"PgStatMain",
+	"RecoveryWalAll",
+	"RecoveryWalStream",
+	"SysLoggerMain",
+	"WalReceiverMain",
+	"WalSenderMain",
+	"WalWriterMain",
+	/* Client */
+	"SecureRead",
+	"SecureWrite",
+	"SSLOpenServer",
+	"WalReceiverWaitStart",
+	"WalSenderWaitForWAL",
+	"WalSenderWriteData",
+	/* Extension */
+	"Extension",
+	/* IPC */
+	"BgWorkerShutdown",
+	"BgWorkerStartup",
+	"ExecuteGather",
+	"MessageQueueInternal",
+	"MessageQueuePutMessage",
+	"MessageQueueReceive",
+	"MessageQueueSend",
+	"ParallelFinish",
+	"ProcSignal",
+	"ProcSleep",
+	"SyncRep",
+	/* Timeout */
+	"BaseBackupThrottle",
+	"PgSleep",
+	"RecoveryApplyDelay"
+};
+
 #ifndef WIN32
 /* Are we currently in WaitLatch? The signal handler would like to know. */
 static volatile sig_atomic_t waiting = false;
@@ -292,14 +337,19 @@ DisownLatch(volatile Latch *latch)
  * backend-local latch initialized with InitLatch, or a shared latch
  * associated with the current process by calling OwnLatch.
  *
+ * pgstat_desc can be used to define what the wait event is when waiting for
+ * this latch when activity is reported to pgstat.
+ *
  * Returns bit mask indicating which condition(s) caused the wake-up. Note
  * that if multiple wake-up conditions are true, there is no guarantee that
  * we return all of them in one call, but we will return at least one.
  */
 int
-WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
+WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+		  uint32 pgstat_desc)
 {
-	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout);
+	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout,
+							 pgstat_desc);
 }
 
 /*
@@ -310,13 +360,16 @@ WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
  * returning the socket as readable/writable or both, depending on
  * WL_SOCKET_READABLE/WL_SOCKET_WRITEABLE being specified.
  *
+ * pgstat_desc can be used to define what the wait event is when waiting for
+ * this latch or socket when activity is reported to pgstat.
+ *
  * NB: These days this is just a wrapper around the WaitEventSet API. When
  * using a latch very frequently, consider creating a longer living
  * WaitEventSet instead; that's more efficient.
  */
 int
 WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
-				  long timeout)
+				  long timeout, uint32 pgstat_desc)
 {
 	int			ret = 0;
 	int			rc;
@@ -344,7 +397,7 @@ WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
 		AddWaitEventToSet(set, ev, sock, NULL, NULL);
 	}
 
-	rc = WaitEventSetWait(set, timeout, &event, 1);
+	rc = WaitEventSetWait(set, timeout, &event, 1, pgstat_desc);
 
 	if (rc == 0)
 		ret |= WL_TIMEOUT;
@@ -856,6 +909,9 @@ WaitEventAdjustWin32(WaitEventSet *set, WaitEvent *event)
  * If timeout = -1, block until an event occurs; if 0, check sockets for
  * readiness, but don't block; if > 0, block for at most timeout miliseconds.
  *
+ * pgstat_desc can be used to define what the wait event is when waiting for
+ * events to happen when activity is reported to pgstat.
+ *
  * Returns the number of events occurred, or 0 if the timeout was reached.
  *
  * Returned events will have the fd, pos, user_data fields set to the
@@ -863,7 +919,8 @@ WaitEventAdjustWin32(WaitEventSet *set, WaitEvent *event)
  */
 int
 WaitEventSetWait(WaitEventSet *set, long timeout,
-				 WaitEvent *occurred_events, int nevents)
+				 WaitEvent *occurred_events, int nevents,
+				 uint32 pgstat_desc)
 {
 	int			returned_events = 0;
 	instr_time	start_time;
@@ -872,6 +929,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 
 	Assert(nevents > 0);
 
+	pgstat_report_wait_start(pgstat_desc);
+
 	/*
 	 * Initialize timeout if requested.  We must record the current time so
 	 * that we can determine the remaining timeout if interrupted.
@@ -960,6 +1019,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 	waiting = false;
 #endif
 
+	pgstat_report_wait_end();
+
 	return returned_events;
 }
 
@@ -1491,6 +1552,22 @@ WaitEventSetWaitBlock(WaitEventSet *set, int cur_timeout,
 }
 #endif
 
+
+/*
+ * Return an event name for a WaitEventSet event depending on the ID
+ * provided by caller, ID used for the statistics collector.
+ */
+const char *
+GetWaitEventIdentifier(uint16 eventId)
+{
+	StaticAssertStmt(lengthof(WaitEventNames) == WAIT_EVENT_LAST_TYPE + 1,
+					 "WaitEventEntries must match WaitEventIdentifiers");
+	if (eventId > WAIT_EVENT_LAST_TYPE)
+		return "???";
+	return WaitEventNames[eventId];
+}
+
+
 /*
  * SetLatch uses SIGUSR1 to wake up the process waiting on the latch.
  *
diff --git a/src/backend/storage/ipc/shm_mq.c b/src/backend/storage/ipc/shm_mq.c
index 5b32782..9019f6f 100644
--- a/src/backend/storage/ipc/shm_mq.c
+++ b/src/backend/storage/ipc/shm_mq.c
@@ -19,6 +19,7 @@
 #include "postgres.h"
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/bgworker.h"
 #include "storage/procsignal.h"
 #include "storage/shm_mq.h"
@@ -894,7 +895,8 @@ shm_mq_send_bytes(shm_mq_handle *mqh, Size nbytes, const void *data,
 			 * at top of loop, because setting an already-set latch is much
 			 * cheaper than setting one that has been reset.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0,
+					  pgstat_make_wait_desc(WAIT_IPC, WAIT_EVENT_MQ_SEND));
 
 			/* Reset the latch so we don't spin. */
 			ResetLatch(MyLatch);
@@ -991,7 +993,8 @@ shm_mq_receive_bytes(shm_mq *mq, Size bytes_needed, bool nowait,
 		 * loop, because setting an already-set latch is much cheaper than
 		 * setting one that has been reset.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0,
+				  pgstat_make_wait_desc(WAIT_IPC, WAIT_EVENT_MQ_RECEIVE));
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
@@ -1090,7 +1093,8 @@ shm_mq_wait_internal(volatile shm_mq *mq, PGPROC *volatile * ptr,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0,
+				  pgstat_make_wait_desc(WAIT_IPC, WAIT_EVENT_MQ_INTERNAL));
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/backend/storage/ipc/standby.c b/src/backend/storage/ipc/standby.c
index 547f1a8..2d824be 100644
--- a/src/backend/storage/ipc/standby.c
+++ b/src/backend/storage/ipc/standby.c
@@ -354,9 +354,12 @@ ResolveRecoveryConflictWithDatabase(Oid dbid)
  *
  * Deadlocks involving the Startup process and an ordinary backend process
  * will be detected by the deadlock detector within the ordinary backend.
+ *
+ * pgstat_desc can be used to define the wait event this conflict resolution
+ * should wait for pgstat tracking.
  */
 void
-ResolveRecoveryConflictWithLock(LOCKTAG locktag)
+ResolveRecoveryConflictWithLock(LOCKTAG locktag, uint32 pgstat_desc)
 {
 	TimestampTz ltime;
 
@@ -389,7 +392,7 @@ ResolveRecoveryConflictWithLock(LOCKTAG locktag)
 	}
 
 	/* Wait to be signaled by the release of the Relation Lock */
-	ProcWaitForSignal();
+	ProcWaitForSignal(pgstat_desc);
 
 	/*
 	 * Clear any timeout requests established above.  We assume here that the
@@ -426,9 +429,12 @@ ResolveRecoveryConflictWithLock(LOCKTAG locktag)
  * Deadlocks are extremely rare, and relatively expensive to check for,
  * so we don't do a deadlock check right away ... only if we have had to wait
  * at least deadlock_timeout.
+ *
+ * pgstat_desc can be used to override the wait event this recovery conflict
+ * is waiting for when reporting to pgstat.
  */
 void
-ResolveRecoveryConflictWithBufferPin(void)
+ResolveRecoveryConflictWithBufferPin(uint32 pgstat_desc)
 {
 	TimestampTz ltime;
 
@@ -469,7 +475,7 @@ ResolveRecoveryConflictWithBufferPin(void)
 	}
 
 	/* Wait to be signaled by UnpinBuffer() */
-	ProcWaitForSignal();
+	ProcWaitForSignal(pgstat_desc);
 
 	/*
 	 * Clear any timeout requests established above.  We assume here that the
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index dba3809..d2e2331 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -1659,6 +1659,7 @@ WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
 	LOCKMETHODID lockmethodid = LOCALLOCK_LOCKMETHOD(*locallock);
 	LockMethod	lockMethodTable = LockMethods[lockmethodid];
 	char	   *volatile new_status = NULL;
+	uint32		pgstat_desc;
 
 	LOCK_PRINT("WaitOnLock: sleeping on lock",
 			   locallock->lock, locallock->tag.mode);
@@ -1676,7 +1677,9 @@ WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
 		set_ps_display(new_status, false);
 		new_status[len] = '\0'; /* truncate off " waiting" */
 	}
-	pgstat_report_wait_start(WAIT_LOCK, locallock->tag.lock.locktag_type);
+
+	pgstat_desc = pgstat_make_wait_desc(WAIT_LOCK,
+										locallock->tag.lock.locktag_type);
 
 	awaitedLock = locallock;
 	awaitedOwner = owner;
@@ -1700,7 +1703,7 @@ WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
 	 */
 	PG_TRY();
 	{
-		if (ProcSleep(locallock, lockMethodTable) != STATUS_OK)
+		if (ProcSleep(locallock, lockMethodTable, pgstat_desc) != STATUS_OK)
 		{
 			/*
 			 * We failed as a result of a deadlock, see CheckDeadLock(). Quit
@@ -1724,7 +1727,6 @@ WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
 		/* In this path, awaitedLock remains set until LockErrorCleanup */
 
 		/* Report change to non-waiting status */
-		pgstat_report_wait_end();
 		if (update_process_title)
 		{
 			set_ps_display(new_status, false);
@@ -1739,7 +1741,6 @@ WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
 	awaitedLock = NULL;
 
 	/* Report change to non-waiting status */
-	pgstat_report_wait_end();
 	if (update_process_title)
 	{
 		set_ps_display(new_status, false);
diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c
index 9d08de7..caf018b 100644
--- a/src/backend/storage/lmgr/lwlock.c
+++ b/src/backend/storage/lmgr/lwlock.c
@@ -730,11 +730,16 @@ static inline void
 LWLockReportWaitStart(LWLock *lock)
 {
 	int			lockId = T_ID(lock);
+	uint32		pgstat_desc;
 
 	if (lock->tranche == 0)
-		pgstat_report_wait_start(WAIT_LWLOCK_NAMED, (uint16) lockId);
+		pgstat_desc = pgstat_make_wait_desc(WAIT_LWLOCK_NAMED,
+											(uint16) lockId);
 	else
-		pgstat_report_wait_start(WAIT_LWLOCK_TRANCHE, lock->tranche);
+		pgstat_desc = pgstat_make_wait_desc(WAIT_LWLOCK_TRANCHE,
+											lock->tranche);
+
+	pgstat_report_wait_start(pgstat_desc);
 }
 
 /*
diff --git a/src/backend/storage/lmgr/predicate.c b/src/backend/storage/lmgr/predicate.c
index 4064b20..f292834 100644
--- a/src/backend/storage/lmgr/predicate.c
+++ b/src/backend/storage/lmgr/predicate.c
@@ -1518,7 +1518,7 @@ GetSafeSnapshot(Snapshot origSnapshot)
 				 SxactIsROUnsafe(MySerializableXact)))
 		{
 			LWLockRelease(SerializableXactHashLock);
-			ProcWaitForSignal();
+			ProcWaitForSignal(0);
 			LWLockAcquire(SerializableXactHashLock, LW_EXCLUSIVE);
 		}
 		MySerializableXact->flags &= ~SXACT_FLAG_DEFERRABLE_WAITING;
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 33e7023..6ef0d94 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -39,6 +39,7 @@
 #include "access/twophase.h"
 #include "access/xact.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/autovacuum.h"
 #include "replication/slot.h"
 #include "replication/syncrep.h"
@@ -977,6 +978,9 @@ ProcQueueInit(PROC_QUEUE *queue)
  * The lock table's partition lock must be held at entry, and will be held
  * at exit.
  *
+ * pgstat_desc tracks what is the wait event caller is expecting to wait for.
+ * If set to 0 the default wait event for ProcSleep() is used.
+ *
  * Result: STATUS_OK if we acquired the lock, STATUS_ERROR if not (deadlock).
  *
  * ASSUME: that no one will fiddle with the queue until after
@@ -985,7 +989,8 @@ ProcQueueInit(PROC_QUEUE *queue)
  * NOTES: The process queue is now a priority queue for locking.
  */
 int
-ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
+ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable,
+		  uint32 pgstat_desc)
 {
 	LOCKMODE	lockmode = locallock->tag.mode;
 	LOCK	   *lock = locallock->lock;
@@ -1023,6 +1028,14 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
 	}
 
 	/*
+	 * If caller did not provide the wait event it is expected to look for,
+	 * set up a default one.
+	 */
+	if (pgstat_desc == 0)
+		pgstat_desc = pgstat_make_wait_desc(WAIT_ACTIVITY,
+											WAIT_EVENT_PROC_SLEEP);
+
+	/*
 	 * Determine where to add myself in the wait queue.
 	 *
 	 * Normally I should go at the end of the queue.  However, if I already
@@ -1208,11 +1221,11 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
 		if (InHotStandby)
 		{
 			/* Set a timer and wait for that or for the Lock to be granted */
-			ResolveRecoveryConflictWithLock(locallock->tag.lock);
+			ResolveRecoveryConflictWithLock(locallock->tag.lock, pgstat_desc);
 		}
 		else
 		{
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, pgstat_desc);
 			ResetLatch(MyLatch);
 			/* check for deadlocks first, as that's probably log-worthy */
 			if (got_deadlock_timeout)
@@ -1717,14 +1730,24 @@ CheckDeadLockAlert(void)
 /*
  * ProcWaitForSignal - wait for a signal from another backend.
  *
+ * pgstat_desc tracks what is the wait event caller is expecting to wait for.
+ * If set to 0 the default wait event for ProcWaitForSignal() is used.
+ *
  * As this uses the generic process latch the caller has to be robust against
  * unrelated wakeups: Always check that the desired state has occurred, and
  * wait again if not.
  */
 void
-ProcWaitForSignal(void)
+ProcWaitForSignal(uint32 pgstat_desc)
 {
-	WaitLatch(MyLatch, WL_LATCH_SET, 0);
+	/*
+	 * If caller did not provide the wait event it is expected to look for,
+	 * set up a default one.
+	 */
+	if (pgstat_desc == 0)
+		pgstat_make_wait_desc(WAIT_IPC, WAIT_EVENT_PROC_SIGNAL);
+
+	WaitLatch(MyLatch, WL_LATCH_SET, 0, pgstat_desc);
 	ResetLatch(MyLatch);
 	CHECK_FOR_INTERRUPTS();
 }
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 5e705e9..02cabcd 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -30,6 +30,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "parser/scansup.h"
+#include "pgstat.h"
 #include "postmaster/syslogger.h"
 #include "rewrite/rewriteHandler.h"
 #include "storage/fd.h"
@@ -560,7 +561,9 @@ pg_sleep(PG_FUNCTION_ARGS)
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | WL_TIMEOUT,
-						 delay_ms);
+						 delay_ms,
+						 pgstat_make_wait_desc(WAIT_TIMEOUT,
+											   WAIT_EVENT_PG_SLEEP));
 		ResetLatch(MyLatch);
 	}
 
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0c98c59..e1557da 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -721,8 +721,13 @@ typedef enum WaitClass
 	WAIT_LWLOCK_NAMED,
 	WAIT_LWLOCK_TRANCHE,
 	WAIT_LOCK,
-	WAIT_BUFFER_PIN
-}	WaitClass;
+	WAIT_BUFFER_PIN,
+	WAIT_ACTIVITY,
+	WAIT_CLIENT,
+	WAIT_EXTENSION,
+	WAIT_IPC,
+	WAIT_TIMEOUT
+} WaitClass;
 
 
 /* ----------
@@ -1018,23 +1023,18 @@ extern void pgstat_initstats(Relation rel);
  * ----------
  */
 static inline void
-pgstat_report_wait_start(uint8 classId, uint16 eventId)
+pgstat_report_wait_start(uint32 wait_event_info)
 {
 	volatile PGPROC *proc = MyProc;
-	uint32		wait_event_val;
 
 	if (!pgstat_track_activities || !proc)
 		return;
 
-	wait_event_val = classId;
-	wait_event_val <<= 24;
-	wait_event_val |= eventId;
-
 	/*
 	 * Since this is a four-byte field which is always read and written as
 	 * four-bytes, updates are atomic.
 	 */
-	proc->wait_event_info = wait_event_val;
+	proc->wait_event_info = wait_event_info;
 }
 
 /* ----------
@@ -1061,6 +1061,16 @@ pgstat_report_wait_end(void)
 	proc->wait_event_info = 0;
 }
 
+/* ----------
+ * pgstat_make_wait_desc()
+ *
+ *	Build a value to be used for report in pgstat_report_wait_start().
+ *	This respects the format per the description above.
+ * ----------
+ */
+#define pgstat_make_wait_desc(classId, eventId)					\
+	((classId << 24) | eventId)
+
 /* nontransactional event counts are simple enough to inline */
 
 #define pgstat_count_heap_scan(rel)									\
diff --git a/src/include/storage/latch.h b/src/include/storage/latch.h
index 5179ecc..baaa6b2 100644
--- a/src/include/storage/latch.h
+++ b/src/include/storage/latch.h
@@ -135,6 +135,70 @@ typedef struct WaitEvent
 	void	   *user_data;		/* pointer provided in AddWaitEventToSet */
 } WaitEvent;
 
+/*
+ * List of WaitEventSet identifiers used when reporting activity to
+ * statistics collector. Up to 256 different WaitEventIdentifier can be
+ * handled. Those are classified by category first, and then by
+ * alphabetical order. Events are classified into sub-categories following
+ * some basic hierarchy rules:
+ * - "Activity" for main loops of processes waiting for an event.
+ * - "Client" for a socket awaited when a user is connected.
+ * - "IPC", similarly to "Client", for a socket awaited from another
+ *   server process.
+ * - "Timeout", for a timeout waiting to expire.
+ * - "Extension", to let extension modules a way to define a custom wait
+ *   point.
+ */
+typedef enum WaitEventIdentifier
+{
+	/* Activity */
+	WAIT_EVENT_ARCHIVER_MAIN,
+	WAIT_EVENT_AUTOVACUUM_MAIN,
+	WAIT_EVENT_BGWRITER_HIBERNATE,
+	WAIT_EVENT_BGWRITER_MAIN,
+	WAIT_EVENT_CHECKPOINTER_MAIN,
+	WAIT_EVENT_PGSTAT_MAIN,
+	WAIT_EVENT_RECOVERY_WAL_ALL,
+	WAIT_EVENT_RECOVERY_WAL_STREAM,
+	WAIT_EVENT_SYSLOGGER_MAIN,
+	WAIT_EVENT_WAL_RECEIVER_MAIN,
+	WAIT_EVENT_WAL_SENDER_MAIN,
+	WAIT_EVENT_WAL_WRITER_MAIN,
+	/* Client */
+	WAIT_EVENT_SECURE_READ,
+	WAIT_EVENT_SECURE_WRITE,
+	WAIT_EVENT_SSL_OPEN_SERVER,
+	WAIT_EVENT_WAL_RECEIVER_WAIT_START,
+	WAIT_EVENT_WAL_SENDER_WAIT_WAL,
+	WAIT_EVENT_WAL_SENDER_WRITE_DATA,
+	/* Extension */
+	WAIT_EVENT_EXTENSION,
+	/* IPC */
+	WAIT_EVENT_BGWORKER_SHUTDOWN,
+	WAIT_EVENT_BGWORKER_STARTUP,
+	WAIT_EVENT_EXECUTE_GATHER,
+	WAIT_EVENT_MQ_INTERNAL,
+	WAIT_EVENT_MQ_PUT_MESSAGE,
+	WAIT_EVENT_MQ_RECEIVE,
+	WAIT_EVENT_MQ_SEND,
+	WAIT_EVENT_PARALLEL_FINISH,
+	WAIT_EVENT_PROC_SIGNAL,
+	WAIT_EVENT_PROC_SLEEP,
+	WAIT_EVENT_SYNC_REP,
+	/* Timeout */
+	WAIT_EVENT_BASE_BACKUP_THROTTLE,
+	WAIT_EVENT_PG_SLEEP,
+	WAIT_EVENT_RECOVERY_APPLY_DELAY
+} WaitEventIdentifier;
+
+#define WAIT_EVENT_LAST_TYPE WAIT_EVENT_RECOVERY_APPLY_DELAY
+
+/*
+ * The information details about each WaitEventIdentifier listed above
+ * are specified by an array of name-pair values.
+ */
+extern const char *const WaitEventName[];
+
 /* forward declaration to avoid exposing latch.c implementation details */
 typedef struct WaitEventSet WaitEventSet;
 
@@ -155,10 +219,14 @@ extern int AddWaitEventToSet(WaitEventSet *set, uint32 events, pgsocket fd,
 				  Latch *latch, void *user_data);
 extern void ModifyWaitEvent(WaitEventSet *set, int pos, uint32 events, Latch *latch);
 
-extern int	WaitEventSetWait(WaitEventSet *set, long timeout, WaitEvent *occurred_events, int nevents);
-extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout);
+extern int	WaitEventSetWait(WaitEventSet *set, long timeout,
+				  WaitEvent *occurred_events, int nevents,
+				  uint32 pgstat_desc);
+extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+				  uint32 pgstat_desc);
 extern int WaitLatchOrSocket(volatile Latch *latch, int wakeEvents,
-				  pgsocket sock, long timeout);
+				  pgsocket sock, long timeout, uint32 pgstat_desc);
+extern const char *GetWaitEventIdentifier(uint16 eventId);
 
 /*
  * Unix implementation uses SIGUSR1 for inter-process signaling.
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index f576f05..158cb26 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -284,14 +284,15 @@ extern bool HaveNFreeProcs(int n);
 extern void ProcReleaseLocks(bool isCommit);
 
 extern void ProcQueueInit(PROC_QUEUE *queue);
-extern int	ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable);
+extern int	ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable,
+					  uint32 pgstat_desc);
 extern PGPROC *ProcWakeup(PGPROC *proc, int waitStatus);
 extern void ProcLockWakeup(LockMethod lockMethodTable, LOCK *lock);
 extern void CheckDeadLockAlert(void);
 extern bool IsWaitingForLock(void);
 extern void LockErrorCleanup(void);
 
-extern void ProcWaitForSignal(void);
+extern void ProcWaitForSignal(uint32 pgstat_desc);
 extern void ProcSendSignal(int pid);
 
 extern void BecomeLockGroupLeader(void);
diff --git a/src/include/storage/standby.h b/src/include/storage/standby.h
index dcebf72..9e54a3b 100644
--- a/src/include/storage/standby.h
+++ b/src/include/storage/standby.h
@@ -32,8 +32,9 @@ extern void ResolveRecoveryConflictWithSnapshot(TransactionId latestRemovedXid,
 extern void ResolveRecoveryConflictWithTablespace(Oid tsid);
 extern void ResolveRecoveryConflictWithDatabase(Oid dbid);
 
-extern void ResolveRecoveryConflictWithLock(LOCKTAG locktag);
-extern void ResolveRecoveryConflictWithBufferPin(void);
+extern void ResolveRecoveryConflictWithLock(LOCKTAG locktag,
+											uint32 pgstat_desc);
+extern void ResolveRecoveryConflictWithBufferPin(uint32 pgstat_desc);
 extern void CheckRecoveryConflictDeadlock(void);
 extern void StandbyDeadLockHandler(void);
 extern void StandbyTimeoutHandler(void);
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 143df4e..0cfb447 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -16,6 +16,7 @@
 #include "postgres.h"
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/bgworker.h"
 #include "storage/procsignal.h"
 #include "storage/shm_toc.h"
@@ -279,7 +280,9 @@ wait_for_workers_to_become_ready(worker_state *wstate,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0,
+				  pgstat_make_wait_desc(WAIT_EXTENSION,
+										WAIT_EVENT_EXTENSION));
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/test/modules/test_shm_mq/test.c b/src/test/modules/test_shm_mq/test.c
index dd34bc7..2953062 100644
--- a/src/test/modules/test_shm_mq/test.c
+++ b/src/test/modules/test_shm_mq/test.c
@@ -15,6 +15,7 @@
 
 #include "fmgr.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 
 #include "test_shm_mq.h"
 
@@ -230,7 +231,9 @@ test_shm_mq_pipelined(PG_FUNCTION_ARGS)
 			 * have read or written data and therefore there may now be work
 			 * for us to do.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0,
+					  pgstat_make_wait_desc(WAIT_EXTENSION,
+											WAIT_EVENT_EXTENSION));
 			ResetLatch(MyLatch);
 			CHECK_FOR_INTERRUPTS();
 		}
diff --git a/src/test/modules/worker_spi/worker_spi.c b/src/test/modules/worker_spi/worker_spi.c
index 7c9a3eb..531eb22 100644
--- a/src/test/modules/worker_spi/worker_spi.c
+++ b/src/test/modules/worker_spi/worker_spi.c
@@ -227,7 +227,9 @@ worker_spi_main(Datum main_arg)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   worker_spi_naptime * 1000L);
+					   worker_spi_naptime * 1000L,
+					   pgstat_make_wait_desc(WAIT_EXTENSION,
+											 WAIT_EVENT_EXTENSION));
 		ResetLatch(MyLatch);
 
 		/* emergency bailout if postmaster has died */

diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 8ca1c1c..9badfe6 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -17,6 +17,7 @@
 #include "access/xact.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "storage/latch.h"
 #include "utils/hsearch.h"
 #include "utils/memutils.h"
@@ -496,7 +497,7 @@ pgfdw_get_result(PGconn *conn, const char *query)
 			wc = WaitLatchOrSocket(MyLatch,
 								   WL_LATCH_SET | WL_SOCKET_READABLE,
 								   PQsocket(conn),
-								   -1L);
+								   -1L, WAIT_EXTENSION);
 			ResetLatch(MyLatch);
 
 			CHECK_FOR_INTERRUPTS();
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index f400785..c5d7728 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -679,6 +679,42 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
           buffer in question.
          </para>
         </listitem>
+        <listitem>
+         <para>
+          <literal>Activity</>: The server process is idle.  This is used by
+          system processes waiting for activity in their main processing loop.
+          <literal>wait_event</> will identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Extension</>: The server process is waiting for activity
+          in an extension module.  This category is useful for modules to
+          track custom waiting points.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Client</>: The server process is waiting for some activity
+          on a socket from user applications, and that the server expects
+          something to happen that is independent from its internal processes.
+          <literal>wait_event</> will identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>IPC</>: The server process is waiting for some activity
+          from another process in the server.  <literal>wait_event</> will
+          identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Timeout</>: The server process is waiting for a timeout
+          to expire.  <literal>wait_event</> will identify the specific wait
+          point.
+         </para>
+        </listitem>
        </itemizedlist>
       </entry>
      </row>
@@ -1085,6 +1121,139 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
          <entry><literal>BufferPin</></entry>
          <entry>Waiting to acquire a pin on a buffer.</entry>
         </row>
+        <row>
+         <entry morerows="11"><literal>Activity</></entry>
+         <entry><literal>ArchiverMain</></entry>
+         <entry>Waiting in main loop of the archiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>AutoVacuumMain</></entry>
+         <entry>Waiting in main loop of autovacuum launcher process.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterHibernate</></entry>
+         <entry>Waiting in background writer process, hibernating.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterMain</></entry>
+         <entry>Waiting in main loop of background writer process background worker.</entry>
+        </row>
+        <row>
+         <entry><literal>CheckpointerMain</></entry>
+         <entry>Waiting in main loop of checkpointer process.</entry>
+        </row>
+        <row>
+         <entry><literal>PgStatMain</></entry>
+         <entry>Waiting in main loop of the statistics collector process.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalAll</></entry>
+         <entry>Waiting for WAL from any kind of source (local, archive or stream) at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalStream</></entry>
+         <entry>Waiting for WAL from a stream at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>SysLoggerMain</></entry>
+         <entry>Waiting in main loop of syslogger process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverMain</></entry>
+         <entry>Waiting in main loop of WAL receiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderMain</></entry>
+         <entry>Waiting in main loop of WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalWriterMain</></entry>
+         <entry>Waiting in main loop of WAL writer process.</entry>
+        </row>
+        <row>
+         <entry morerows="5"><literal>Client</></entry>
+         <entry><literal>ClientRead</></entry>
+         <entry>Waiting to read data from the client.</entry>
+        </row>
+        <row>
+         <entry><literal>ClientWrite</></entry>
+         <entry>Waiting to write data from the client.</entry>
+        </row>
+        <row>
+         <entry><literal>SSLOpenServer</></entry>
+         <entry>Waiting for SSL while attempting connection.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverWaitStart</></entry>
+         <entry>Waiting for startup process to send initial data for streaming replication.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWaitForWAL</></entry>
+         <entry>Waiting for WAL to be flushed in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWriteData</></entry>
+         <entry>Waiting for any activity when processing replies from WAL receiver in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>Extension</></entry>
+         <entry><literal>Extension</></entry>
+         <entry>Waiting in an extension.</entry>
+        </row>
+        <row>
+         <entry morerows="10"><literal>IPC</></entry>
+         <entry><literal>BgWorkerShutdown</></entry>
+         <entry>Waiting for background worker to shut down.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWorkerStartup</></entry>
+         <entry>Waiting for background worker to start up.</entry>
+        </row>
+        <row>
+         <entry><literal>ExecuteGather</></entry>
+         <entry>Waiting for activity from child process when executing <literal>Gather</> node.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueInternal</></entry>
+         <entry>Waiting for other process to be attached in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueuePutMessage</></entry>
+         <entry>Waiting to write a protoocol message to a shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueReceive</></entry>
+         <entry>Waiting to receive bytes from a shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueSend</></entry>
+         <entry>Waiting to send bytes to a shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>ParallelFinish</></entry>
+         <entry>Waiting for parallel workers to finish computing.</entry>
+        </row>
+        <row>
+         <entry><literal>SafeSnapshot</></entry>
+         <entry>Waiting for a snapshot for a <literal>READ ONLY DEFERRABLE</> transaction.</entry>
+        </row>
+        <row>
+         <entry><literal>SyncRep</></entry>
+         <entry>Waiting for confirmation from remote server during synchronous replication.</entry>
+        </row>
+        <row>
+         <entry morerows="2"><literal>Timeout</></entry>
+         <entry><literal>BaseBackupThrottle</></entry>
+         <entry>Waiting during base backup when throttling activity.</entry>
+        </row>
+        <row>
+         <entry><literal>PgSleep</></entry>
+         <entry>Waiting in process that called <function>pg_sleep</>.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryApplyDelay</></entry>
+         <entry>Waiting to apply WAL at recovery because it is delayed.</entry>
+        </row>
       </tbody>
      </tgroup>
     </table>
diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c
index cde0ed3..59dc394 100644
--- a/src/backend/access/transam/parallel.c
+++ b/src/backend/access/transam/parallel.c
@@ -24,6 +24,7 @@
 #include "libpq/pqmq.h"
 #include "miscadmin.h"
 #include "optimizer/planmain.h"
+#include "pgstat.h"
 #include "storage/ipc.h"
 #include "storage/sinval.h"
 #include "storage/spin.h"
@@ -540,7 +541,8 @@ WaitForParallelWorkersToFinish(ParallelContext *pcxt)
 		if (!anyone_alive)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1,
+				  WAIT_EVENT_PARALLEL_FINISH);
 		ResetLatch(&MyProc->procLatch);
 	}
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index c1b9a97..08c87f9 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5827,7 +5827,8 @@ recoveryApplyDelay(XLogReaderState *record)
 
 		WaitLatch(&XLogCtl->recoveryWakeupLatch,
 				  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-				  secs * 1000L + microsecs / 1000);
+				  secs * 1000L + microsecs / 1000,
+				  WAIT_EVENT_RECOVERY_APPLY_DELAY);
 	}
 	return true;
 }
@@ -11387,7 +11388,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 
 						WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								  wait_time);
+								  wait_time, WAIT_EVENT_RECOVERY_WAL_STREAM);
 						ResetLatch(&XLogCtl->recoveryWakeupLatch);
 						now = GetCurrentTimestamp();
 					}
@@ -11550,7 +11551,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					 */
 					WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							  5000L);
+							  5000L, WAIT_EVENT_RECOVERY_WAL_ALL);
 					ResetLatch(&XLogCtl->recoveryWakeupLatch);
 					break;
 				}
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 438d1b2..880ca62 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -38,6 +38,7 @@
 #include "executor/nodeSubplan.h"
 #include "executor/tqueue.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "utils/memutils.h"
 #include "utils/rel.h"
 
@@ -387,7 +388,7 @@ gather_readnext(GatherState *gatherstate)
 				return NULL;
 
 			/* Nothing to do except wait for developments. */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_EVENT_EXECUTE_GATHER);
 			ResetLatch(MyLatch);
 			nvisited = 0;
 		}
diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
index fedb02c..668f217 100644
--- a/src/backend/libpq/be-secure-openssl.c
+++ b/src/backend/libpq/be-secure-openssl.c
@@ -60,6 +60,7 @@
 
 #include "libpq/libpq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "storage/latch.h"
 #include "tcop/tcopprot.h"
 #include "utils/memutils.h"
@@ -419,7 +420,8 @@ aloop:
 				else
 					waitfor = WL_SOCKET_WRITEABLE;
 
-				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0);
+				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0,
+								  WAIT_EVENT_SSL_OPEN_SERVER);
 				goto aloop;
 			case SSL_ERROR_SYSCALL:
 				if (r < 0)
diff --git a/src/backend/libpq/be-secure.c b/src/backend/libpq/be-secure.c
index cdd07d5..b267507 100644
--- a/src/backend/libpq/be-secure.c
+++ b/src/backend/libpq/be-secure.c
@@ -33,6 +33,7 @@
 
 #include "libpq/libpq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "tcop/tcopprot.h"
 #include "utils/memutils.h"
 #include "storage/ipc.h"
@@ -146,7 +147,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 WAIT_EVENT_CLIENT_READ);
 
 		/*
 		 * If the postmaster has died, it's not safe to continue running,
@@ -247,7 +249,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 WAIT_EVENT_CLIENT_WRITE);
 
 		/* See comments in secure_read. */
 		if (event.events & WL_POSTMASTER_DEATH)
diff --git a/src/backend/libpq/pqmq.c b/src/backend/libpq/pqmq.c
index bfe66c6..f93ccae 100644
--- a/src/backend/libpq/pqmq.c
+++ b/src/backend/libpq/pqmq.c
@@ -17,6 +17,7 @@
 #include "libpq/pqformat.h"
 #include "libpq/pqmq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "tcop/tcopprot.h"
 #include "utils/builtins.h"
 
@@ -171,7 +172,8 @@ mq_putmessage(char msgtype, const char *s, size_t len)
 		if (result != SHM_MQ_WOULD_BLOCK)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0,
+				  WAIT_EVENT_MQ_PUT_MESSAGE);
 		ResetLatch(&MyProc->procLatch);
 		CHECK_FOR_INTERRUPTS();
 	}
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 1a92ca1..e3a6911 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -598,7 +598,8 @@ AutoVacLauncherMain(int argc, char *argv[])
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L));
+					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L),
+					   WAIT_EVENT_AUTOVACUUM_MAIN);
 
 		ResetLatch(MyLatch);
 
diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c
index 699c934..028a9ee 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -18,6 +18,7 @@
 #include "libpq/pqsignal.h"
 #include "postmaster/bgworker_internals.h"
 #include "postmaster/postmaster.h"
+#include "pgstat.h"
 #include "storage/barrier.h"
 #include "storage/dsm.h"
 #include "storage/ipc.h"
@@ -969,7 +970,8 @@ WaitForBackgroundWorkerStartup(BackgroundWorkerHandle *handle, pid_t *pidp)
 			break;
 
 		rc = WaitLatch(MyLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   WAIT_EVENT_BGWORKER_STARTUP);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
@@ -1008,7 +1010,8 @@ WaitForBackgroundWorkerShutdown(BackgroundWorkerHandle *handle)
 			break;
 
 		rc = WaitLatch(&MyProc->procLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   WAIT_EVENT_BGWORKER_SHUTDOWN);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index 1002034..c3f3356 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -345,7 +345,7 @@ BackgroundWriterMain(void)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   BgWriterDelay /* ms */ );
+					   BgWriterDelay /* ms */, WAIT_EVENT_BGWRITER_MAIN);
 
 		/*
 		 * If no latch event and BgBufferSync says nothing's happening, extend
@@ -372,7 +372,8 @@ BackgroundWriterMain(void)
 			/* Sleep ... */
 			rc = WaitLatch(MyLatch,
 						   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-						   BgWriterDelay * HIBERNATE_FACTOR);
+						   BgWriterDelay * HIBERNATE_FACTOR,
+						   WAIT_EVENT_BGWRITER_HIBERNATE);
 			/* Reset the notification request in case we timed out */
 			StrategyNotifyBgWriter(-1);
 		}
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index d702a48..397267c 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -556,7 +556,8 @@ CheckpointerMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout * 1000L /* convert to ms */ );
+					   cur_timeout * 1000L /* convert to ms */,
+					   WAIT_EVENT_CHECKPOINTER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 1aa6466..62783d9 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -390,7 +390,8 @@ pgarch_MainLoop(void)
 
 				rc = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							   timeout * 1000L);
+							   timeout * 1000L,
+							   WAIT_EVENT_ARCHIVER_MAIN);
 				if (rc & WL_TIMEOUT)
 					wakened = true;
 			}
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 96578dc..deadf65 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -276,6 +276,11 @@ static PgStat_TableStatus *get_tabstat_entry(Oid rel_id, bool isshared);
 
 static void pgstat_setup_memcxt(void);
 
+static const char *pgstat_get_wait_activity(WaitEventActivity w);
+static const char *pgstat_get_wait_client(WaitEventClient w);
+static const char *pgstat_get_wait_ipc(WaitEventIPC w);
+static const char *pgstat_get_wait_timeout(WaitEventTimeout w);
+
 static void pgstat_setheader(PgStat_MsgHdr *hdr, StatMsgType mtype);
 static void pgstat_send(void *msg, int len);
 
@@ -3131,15 +3136,14 @@ pgstat_read_current_status(void)
 const char *
 pgstat_get_wait_event_type(uint32 wait_event_info)
 {
-	uint8		classId;
+	uint32		classId;
 	const char *event_type;
 
 	/* report process as not waiting. */
 	if (wait_event_info == 0)
 		return NULL;
 
-	wait_event_info = wait_event_info >> 24;
-	classId = wait_event_info & 0XFF;
+	classId = wait_event_info & 0xFF000000;
 
 	switch (classId)
 	{
@@ -3155,6 +3159,18 @@ pgstat_get_wait_event_type(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_type = "BufferPin";
 			break;
+		case WAIT_ACTIVITY:
+			event_type = "Activity";
+			break;
+		case WAIT_CLIENT:
+			event_type = "Client";
+			break;
+		case WAIT_EXTENSION:
+			event_type = "Extension";
+			break;
+		case WAIT_TIMEOUT:
+			event_type = "Timeout";
+			break;
 		default:
 			event_type = "???";
 			break;
@@ -3172,7 +3188,7 @@ pgstat_get_wait_event_type(uint32 wait_event_info)
 const char *
 pgstat_get_wait_event(uint32 wait_event_info)
 {
-	uint8		classId;
+	uint32		classId;
 	uint16		eventId;
 	const char *event_name;
 
@@ -3180,9 +3196,8 @@ pgstat_get_wait_event(uint32 wait_event_info)
 	if (wait_event_info == 0)
 		return NULL;
 
-	eventId = wait_event_info & ((1 << 24) - 1);
-	wait_event_info = wait_event_info >> 24;
-	classId = wait_event_info & 0XFF;
+	classId = wait_event_info & 0xFF000000;
+	eventId = wait_event_info & 0x0000FFFF;
 
 	switch (classId)
 	{
@@ -3196,6 +3211,37 @@ pgstat_get_wait_event(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_name = "BufferPin";
 			break;
+		case WAIT_ACTIVITY:
+			{
+				WaitEventActivity	w = (WaitEventActivity) wait_event_info;
+
+				event_name = pgstat_get_wait_activity(w);
+				break;
+			}
+		case WAIT_CLIENT:
+			{
+				WaitEventClient	w = (WaitEventClient) wait_event_info;
+
+				event_name = pgstat_get_wait_client(w);
+				break;
+			}
+		case WAIT_EXTENSION:
+			event_name = "Extension";
+			break;
+		case WAIT_IPC:
+			{
+				WaitEventIPC	w = (WaitEventIPC) wait_event_info;
+
+				event_name = pgstat_get_wait_ipc(w);
+				break;
+			}
+		case WAIT_TIMEOUT:
+			{
+				WaitEventTimeout	w = (WaitEventTimeout) wait_event_info;
+
+				event_name = pgstat_get_wait_timeout(w);
+				break;
+			}
 		default:
 			event_name = "unknown wait event";
 			break;
@@ -3205,6 +3251,175 @@ pgstat_get_wait_event(uint32 wait_event_info)
 }
 
 /* ----------
+ * pgstat_get_wait_activity() -
+ *
+ * Convert WaitEventActivity to string.
+ * ----------
+ */
+static const char *
+pgstat_get_wait_activity(WaitEventActivity w)
+{
+	const char *event_name = "unknown wait event";
+
+	switch (w)
+	{
+		case WAIT_EVENT_ARCHIVER_MAIN:
+			event_name = "ArchiverMain";
+			break;
+		case WAIT_EVENT_AUTOVACUUM_MAIN:
+			event_name = "AutoVacuumMain";
+			break;
+		case WAIT_EVENT_BGWRITER_HIBERNATE:
+			event_name = "BgWriterHibernate";
+			break;
+		case WAIT_EVENT_BGWRITER_MAIN:
+			event_name = "BgWriterMain";
+			break;
+		case WAIT_EVENT_CHECKPOINTER_MAIN:
+			event_name = "CheckpointerMain";
+			break;
+		case WAIT_EVENT_PGSTAT_MAIN:
+			event_name = "PgStatMain";
+			break;
+		case WAIT_EVENT_RECOVERY_WAL_ALL:
+			event_name = "RecoveryWalAll";
+			break;
+		case WAIT_EVENT_RECOVERY_WAL_STREAM:
+			event_name = "RecoveryWalStream";
+			break;
+		case WAIT_EVENT_SYSLOGGER_MAIN:
+			event_name = "SysLoggerMain";
+			break;
+		case WAIT_EVENT_WAL_RECEIVER_MAIN:
+			event_name = "WalReceiverMain";
+			break;
+		case WAIT_EVENT_WAL_SENDER_MAIN:
+			event_name = "WalSenderMain";
+			break;
+		case WAIT_EVENT_WAL_WRITER_MAIN:
+			event_name = "WalWriterMain";
+			break;
+		/* no default case, so that compiler will warn */
+	}
+
+	return event_name;
+}
+
+/* ----------
+ * pgstat_get_wait_client() -
+ *
+ * Convert WaitEventClient to string.
+ * ----------
+ */
+static const char *
+pgstat_get_wait_client(WaitEventClient w)
+{
+	const char *event_name = "unknown wait event";
+
+	switch (w)
+	{
+		case WAIT_EVENT_CLIENT_READ:
+			event_name = "ClientRead";
+			break;
+		case WAIT_EVENT_CLIENT_WRITE:
+			event_name = "ClientWrite";
+			break;
+		case WAIT_EVENT_SSL_OPEN_SERVER:
+			event_name = "SSLOpenServer";
+			break;
+		case WAIT_EVENT_WAL_RECEIVER_WAIT_START:
+			event_name = "WalReceiverWaitStart";
+			break;
+		case WAIT_EVENT_WAL_SENDER_WAIT_WAL:
+			event_name = "WalSenderWaitForWAL";
+			break;
+		case WAIT_EVENT_WAL_SENDER_WRITE_DATA:
+			event_name = "WalSenderWriteData";
+			break;
+		/* no default case, so that compiler will warn */
+	}
+
+	return event_name;
+}
+
+/* ----------
+ * pgstat_get_wait_ipc() -
+ *
+ * Convert WaitEventIPC to string.
+ * ----------
+ */
+static const char *
+pgstat_get_wait_ipc(WaitEventIPC w)
+{
+	const char *event_name = "unknown wait event";
+
+	switch (w)
+	{
+		case WAIT_EVENT_BGWORKER_SHUTDOWN:
+			event_name = "BgWorkerShutdown";
+			break;
+		case WAIT_EVENT_BGWORKER_STARTUP:
+			event_name = "BgWorkerStartup";
+			break;
+		case WAIT_EVENT_EXECUTE_GATHER:
+			event_name = "ExecuteGather";
+			break;
+		case WAIT_EVENT_MQ_INTERNAL:
+			event_name = "MessageQueueInternal";
+			break;
+		case WAIT_EVENT_MQ_PUT_MESSAGE:
+			event_name = "MessageQueuePutMessage";
+			break;
+		case WAIT_EVENT_MQ_RECEIVE:
+			event_name = "MessageQueueReceive";
+			break;
+		case WAIT_EVENT_MQ_SEND:
+			event_name = "MessageQueueSend";
+			break;
+		case WAIT_EVENT_PARALLEL_FINISH:
+			event_name = "ParallelFinish";
+			break;
+		case WAIT_EVENT_SAFE_SNAPSHOT:
+			event_name = "SafeSnapshot";
+			break;
+		case WAIT_EVENT_SYNC_REP:
+			event_name = "SyncRep";
+			break;
+		/* no default case, so that compiler will warn */
+	}
+
+	return event_name;
+}
+
+/* ----------
+ * pgstat_get_wait_timeout() -
+ *
+ * Convert WaitEventTimeout to string.
+ * ----------
+ */
+static const char *
+pgstat_get_wait_timeout(WaitEventTimeout w)
+{
+	const char *event_name = "unknown wait event";
+
+	switch (w)
+	{
+		case WAIT_EVENT_BASE_BACKUP_THROTTLE:
+			event_name = "BaseBackupThrottle";
+			break;
+		case WAIT_EVENT_PG_SLEEP:
+			event_name = "PgSleep";
+			break;
+		case WAIT_EVENT_RECOVERY_APPLY_DELAY:
+			event_name = "RecoveryApplyDelay";
+			break;
+		/* no default case, so that compiler will warn */
+	}
+
+	return event_name;
+}
+
+/* ----------
  * pgstat_get_backend_current_activity() -
  *
  *	Return a string representing the current activity of the backend with
@@ -3684,8 +3899,8 @@ PgstatCollectorMain(int argc, char *argv[])
 #ifndef WIN32
 		wr = WaitLatchOrSocket(MyLatch,
 					 WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE,
-							   pgStatSock,
-							   -1L);
+							   pgStatSock, -1L,
+							   WAIT_EVENT_PGSTAT_MAIN);
 #else
 
 		/*
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index e7e488a..af71367 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -35,6 +35,7 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "nodes/pg_list.h"
+#include "pgstat.h"
 #include "pgtime.h"
 #include "postmaster/fork_process.h"
 #include "postmaster/postmaster.h"
@@ -424,7 +425,8 @@ SysLoggerMain(int argc, char *argv[])
 		rc = WaitLatchOrSocket(MyLatch,
 							   WL_LATCH_SET | WL_SOCKET_READABLE | cur_flags,
 							   syslogPipe[0],
-							   cur_timeout);
+							   cur_timeout,
+							   WAIT_EVENT_SYSLOGGER_MAIN);
 
 		if (rc & WL_SOCKET_READABLE)
 		{
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index 11ec56a..67dcff6 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -290,7 +290,8 @@ WalWriterMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout);
+					   cur_timeout,
+					   WAIT_EVENT_WAL_WRITER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index 1eabaef..fa75930 100644
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -1364,7 +1364,8 @@ throttle(size_t increment)
 		 */
 		wait_result = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								(long) (sleep / 1000));
+								(long) (sleep / 1000),
+								WAIT_EVENT_BASE_BACKUP_THROTTLE);
 
 		if (wait_result & WL_LATCH_SET)
 			CHECK_FOR_INTERRUPTS();
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index b442d06..ac29f56 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -61,6 +61,7 @@
 
 #include "access/xact.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "replication/syncrep.h"
 #include "replication/walsender.h"
 #include "replication/walsender_private.h"
@@ -258,7 +259,8 @@ SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
 		 * Wait on latch.  Any condition that should wake us up will set the
 		 * latch, so no need for timeout.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1);
+		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1,
+				  WAIT_EVENT_SYNC_REP);
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 413ee3a..eed6eff 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -55,6 +55,7 @@
 #include "libpq/pqformat.h"
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "replication/walreceiver.h"
 #include "replication/walsender.h"
 #include "storage/ipc.h"
@@ -486,7 +487,8 @@ WalReceiverMain(void)
 								   WL_POSTMASTER_DEATH | WL_SOCKET_READABLE |
 									   WL_TIMEOUT | WL_LATCH_SET,
 									   wait_fd,
-									   NAPTIME_PER_CYCLE);
+									   NAPTIME_PER_CYCLE,
+									   WAIT_EVENT_WAL_RECEIVER_MAIN);
 				if (rc & WL_LATCH_SET)
 				{
 					ResetLatch(&walrcv->latch);
@@ -685,7 +687,8 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 		}
 		SpinLockRelease(&walrcv->mutex);
 
-		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+				  WAIT_EVENT_WAL_RECEIVER_WAIT_START);
 	}
 
 	if (update_process_title)
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index c7743da..0f3ced2 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -1146,7 +1146,8 @@ WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid,
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  WAIT_EVENT_WAL_SENDER_WRITE_DATA);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1272,7 +1273,8 @@ WalSndWaitForWal(XLogRecPtr loc)
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  WAIT_EVENT_WAL_SENDER_WAIT_WAL);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1924,7 +1926,8 @@ WalSndLoop(WalSndSendDataCallback send_data)
 
 			/* Sleep until something happens or we time out */
 			WaitLatchOrSocket(MyLatch, wakeEvents,
-							  MyProcPort->sock, sleeptime);
+							  MyProcPort->sock, sleeptime,
+							  WAIT_EVENT_WAL_SENDER_MAIN);
 		}
 	}
 	return;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 90804a3..91dc24c 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -3635,9 +3635,6 @@ LockBufferForCleanup(Buffer buffer)
 		UnlockBufHdr(bufHdr, buf_state);
 		LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
 
-		/* Report the wait */
-		pgstat_report_wait_start(WAIT_BUFFER_PIN, 0);
-
 		/* Wait to be signaled by UnpinBuffer() */
 		if (InHotStandby)
 		{
@@ -3649,9 +3646,7 @@ LockBufferForCleanup(Buffer buffer)
 			SetStartupBufferPinWaitBufId(-1);
 		}
 		else
-			ProcWaitForSignal();
-
-		pgstat_report_wait_end();
+			ProcWaitForSignal(WAIT_BUFFER_PIN);
 
 		/*
 		 * Remove flag marking us as waiter. Normally this will not be set
diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c
index 9def8a1..8488f94 100644
--- a/src/backend/storage/ipc/latch.c
+++ b/src/backend/storage/ipc/latch.c
@@ -55,6 +55,7 @@
 #endif
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "portability/instr_time.h"
 #include "postmaster/postmaster.h"
 #include "storage/barrier.h"
@@ -297,9 +298,11 @@ DisownLatch(volatile Latch *latch)
  * we return all of them in one call, but we will return at least one.
  */
 int
-WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
+WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+		  uint32 wait_event_info)
 {
-	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout);
+	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout,
+							 wait_event_info);
 }
 
 /*
@@ -316,7 +319,7 @@ WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
  */
 int
 WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
-				  long timeout)
+				  long timeout, uint32 wait_event_info)
 {
 	int			ret = 0;
 	int			rc;
@@ -344,7 +347,7 @@ WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
 		AddWaitEventToSet(set, ev, sock, NULL, NULL);
 	}
 
-	rc = WaitEventSetWait(set, timeout, &event, 1);
+	rc = WaitEventSetWait(set, timeout, &event, 1, wait_event_info);
 
 	if (rc == 0)
 		ret |= WL_TIMEOUT;
@@ -863,7 +866,8 @@ WaitEventAdjustWin32(WaitEventSet *set, WaitEvent *event)
  */
 int
 WaitEventSetWait(WaitEventSet *set, long timeout,
-				 WaitEvent *occurred_events, int nevents)
+				 WaitEvent *occurred_events, int nevents,
+				 uint32 wait_event_info)
 {
 	int			returned_events = 0;
 	instr_time	start_time;
@@ -883,6 +887,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 		cur_timeout = timeout;
 	}
 
+	pgstat_report_wait_start(wait_event_info);
+
 #ifndef WIN32
 	waiting = true;
 #else
@@ -960,6 +966,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 	waiting = false;
 #endif
 
+	pgstat_report_wait_end();
+
 	return returned_events;
 }
 
diff --git a/src/backend/storage/ipc/shm_mq.c b/src/backend/storage/ipc/shm_mq.c
index 5b32782..bfb6703 100644
--- a/src/backend/storage/ipc/shm_mq.c
+++ b/src/backend/storage/ipc/shm_mq.c
@@ -19,6 +19,7 @@
 #include "postgres.h"
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/bgworker.h"
 #include "storage/procsignal.h"
 #include "storage/shm_mq.h"
@@ -894,7 +895,7 @@ shm_mq_send_bytes(shm_mq_handle *mqh, Size nbytes, const void *data,
 			 * at top of loop, because setting an already-set latch is much
 			 * cheaper than setting one that has been reset.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_EVENT_MQ_SEND);
 
 			/* Reset the latch so we don't spin. */
 			ResetLatch(MyLatch);
@@ -991,7 +992,7 @@ shm_mq_receive_bytes(shm_mq *mq, Size bytes_needed, bool nowait,
 		 * loop, because setting an already-set latch is much cheaper than
 		 * setting one that has been reset.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_EVENT_MQ_RECEIVE);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
@@ -1090,7 +1091,7 @@ shm_mq_wait_internal(volatile shm_mq *mq, PGPROC *volatile * ptr,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_EVENT_MQ_INTERNAL);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/backend/storage/ipc/standby.c b/src/backend/storage/ipc/standby.c
index 547f1a8..fb887b3 100644
--- a/src/backend/storage/ipc/standby.c
+++ b/src/backend/storage/ipc/standby.c
@@ -22,6 +22,7 @@
 #include "access/xlog.h"
 #include "access/xloginsert.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "storage/bufmgr.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
@@ -389,7 +390,7 @@ ResolveRecoveryConflictWithLock(LOCKTAG locktag)
 	}
 
 	/* Wait to be signaled by the release of the Relation Lock */
-	ProcWaitForSignal();
+	ProcWaitForSignal(WAIT_LOCK | locktag.locktag_type);
 
 	/*
 	 * Clear any timeout requests established above.  We assume here that the
@@ -469,7 +470,7 @@ ResolveRecoveryConflictWithBufferPin(void)
 	}
 
 	/* Wait to be signaled by UnpinBuffer() */
-	ProcWaitForSignal();
+	ProcWaitForSignal(WAIT_BUFFER_PIN);
 
 	/*
 	 * Clear any timeout requests established above.  We assume here that the
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index dba3809..71a4dd4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -1676,7 +1676,6 @@ WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
 		set_ps_display(new_status, false);
 		new_status[len] = '\0'; /* truncate off " waiting" */
 	}
-	pgstat_report_wait_start(WAIT_LOCK, locallock->tag.lock.locktag_type);
 
 	awaitedLock = locallock;
 	awaitedOwner = owner;
@@ -1724,7 +1723,6 @@ WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
 		/* In this path, awaitedLock remains set until LockErrorCleanup */
 
 		/* Report change to non-waiting status */
-		pgstat_report_wait_end();
 		if (update_process_title)
 		{
 			set_ps_display(new_status, false);
@@ -1739,7 +1737,6 @@ WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
 	awaitedLock = NULL;
 
 	/* Report change to non-waiting status */
-	pgstat_report_wait_end();
 	if (update_process_title)
 	{
 		set_ps_display(new_status, false);
diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c
index 9d08de7..a90b54a 100644
--- a/src/backend/storage/lmgr/lwlock.c
+++ b/src/backend/storage/lmgr/lwlock.c
@@ -732,9 +732,9 @@ LWLockReportWaitStart(LWLock *lock)
 	int			lockId = T_ID(lock);
 
 	if (lock->tranche == 0)
-		pgstat_report_wait_start(WAIT_LWLOCK_NAMED, (uint16) lockId);
+		pgstat_report_wait_start(WAIT_LWLOCK_NAMED | (uint16) lockId);
 	else
-		pgstat_report_wait_start(WAIT_LWLOCK_TRANCHE, lock->tranche);
+		pgstat_report_wait_start(WAIT_LWLOCK_TRANCHE | lock->tranche);
 }
 
 /*
@@ -750,7 +750,7 @@ LWLockReportWaitEnd(void)
  * Return an identifier for an LWLock based on the wait class and event.
  */
 const char *
-GetLWLockIdentifier(uint8 classId, uint16 eventId)
+GetLWLockIdentifier(uint32 classId, uint16 eventId)
 {
 	if (classId == WAIT_LWLOCK_NAMED)
 		return MainLWLockNames[eventId];
diff --git a/src/backend/storage/lmgr/predicate.c b/src/backend/storage/lmgr/predicate.c
index 4064b20..24ed21b 100644
--- a/src/backend/storage/lmgr/predicate.c
+++ b/src/backend/storage/lmgr/predicate.c
@@ -192,6 +192,7 @@
 #include "access/xact.h"
 #include "access/xlog.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "storage/bufmgr.h"
 #include "storage/predicate.h"
 #include "storage/predicate_internals.h"
@@ -1518,7 +1519,7 @@ GetSafeSnapshot(Snapshot origSnapshot)
 				 SxactIsROUnsafe(MySerializableXact)))
 		{
 			LWLockRelease(SerializableXactHashLock);
-			ProcWaitForSignal();
+			ProcWaitForSignal(WAIT_EVENT_SAFE_SNAPSHOT);
 			LWLockAcquire(SerializableXactHashLock, LW_EXCLUSIVE);
 		}
 		MySerializableXact->flags &= ~SXACT_FLAG_DEFERRABLE_WAITING;
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 33e7023..dd76094 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -39,6 +39,7 @@
 #include "access/twophase.h"
 #include "access/xact.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/autovacuum.h"
 #include "replication/slot.h"
 #include "replication/syncrep.h"
@@ -1212,7 +1213,8 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
 		}
 		else
 		{
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0,
+					  WAIT_LOCK | locallock->tag.lock.locktag_type);
 			ResetLatch(MyLatch);
 			/* check for deadlocks first, as that's probably log-worthy */
 			if (got_deadlock_timeout)
@@ -1722,9 +1724,9 @@ CheckDeadLockAlert(void)
  * wait again if not.
  */
 void
-ProcWaitForSignal(void)
+ProcWaitForSignal(uint32 wait_event_info)
 {
-	WaitLatch(MyLatch, WL_LATCH_SET, 0);
+	WaitLatch(MyLatch, WL_LATCH_SET, 0, wait_event_info);
 	ResetLatch(MyLatch);
 	CHECK_FOR_INTERRUPTS();
 }
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 5e705e9..0da051a 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -29,6 +29,7 @@
 #include "common/keywords.h"
 #include "funcapi.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "parser/scansup.h"
 #include "postmaster/syslogger.h"
 #include "rewrite/rewriteHandler.h"
@@ -560,7 +561,8 @@ pg_sleep(PG_FUNCTION_ARGS)
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | WL_TIMEOUT,
-						 delay_ms);
+						 delay_ms,
+						 WAIT_EVENT_PG_SLEEP);
 		ResetLatch(MyLatch);
 	}
 
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0c98c59..b530c01 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -715,15 +715,91 @@ typedef enum BackendState
  * Wait Classes
  * ----------
  */
-typedef enum WaitClass
+#define WAIT_LWLOCK_NAMED			0x01000000U
+#define WAIT_LWLOCK_TRANCHE			0x02000000U
+#define WAIT_LOCK					0x03000000U
+#define WAIT_BUFFER_PIN				0x04000000U
+#define WAIT_ACTIVITY				0x05000000U
+#define WAIT_CLIENT					0x06000000U
+#define WAIT_EXTENSION				0x07000000U
+#define WAIT_IPC					0x08000000U
+#define WAIT_TIMEOUT				0x09000000U
+
+/* ----------
+ * Wait Events - Activity
+ *
+ * Use this category when a process is waiting because it has no work to do,
+ * unless the "Client" or "Timeout" category describes the situation better.
+ * Typically, this should only be used for background processes.
+ * ----------
+ */
+typedef enum
 {
-	WAIT_UNDEFINED,
-	WAIT_LWLOCK_NAMED,
-	WAIT_LWLOCK_TRANCHE,
-	WAIT_LOCK,
-	WAIT_BUFFER_PIN
-}	WaitClass;
+	WAIT_EVENT_ARCHIVER_MAIN = WAIT_ACTIVITY,
+	WAIT_EVENT_AUTOVACUUM_MAIN,
+	WAIT_EVENT_BGWRITER_HIBERNATE,
+	WAIT_EVENT_BGWRITER_MAIN,
+	WAIT_EVENT_CHECKPOINTER_MAIN,
+	WAIT_EVENT_PGSTAT_MAIN,
+	WAIT_EVENT_RECOVERY_WAL_ALL,
+	WAIT_EVENT_RECOVERY_WAL_STREAM,
+	WAIT_EVENT_SYSLOGGER_MAIN,
+	WAIT_EVENT_WAL_RECEIVER_MAIN,
+	WAIT_EVENT_WAL_SENDER_MAIN,
+	WAIT_EVENT_WAL_WRITER_MAIN,
+} WaitEventActivity;
 
+/* ----------
+ * Wait Events - Client
+ *
+ * Use this category when a process is waiting to send data to or receive data
+ * from the frontend process to which it is connected.  This is never used for
+ * a background process, which has no client connection.
+ * ----------
+ */
+typedef enum
+{
+	WAIT_EVENT_CLIENT_READ = WAIT_CLIENT,
+	WAIT_EVENT_CLIENT_WRITE,
+	WAIT_EVENT_SSL_OPEN_SERVER,
+	WAIT_EVENT_WAL_RECEIVER_WAIT_START,
+	WAIT_EVENT_WAL_SENDER_WAIT_WAL,
+	WAIT_EVENT_WAL_SENDER_WRITE_DATA,
+} WaitEventClient;
+
+/* ----------
+ * Wait Events - IPC
+ *
+ * Use this category when a process cannot complete the work it is doing because
+ * it is waiting for a notification from another process.
+ * ----------
+ */
+typedef enum
+{
+	WAIT_EVENT_BGWORKER_SHUTDOWN = WAIT_IPC,
+	WAIT_EVENT_BGWORKER_STARTUP,
+	WAIT_EVENT_EXECUTE_GATHER,
+	WAIT_EVENT_MQ_INTERNAL,
+	WAIT_EVENT_MQ_PUT_MESSAGE,
+	WAIT_EVENT_MQ_RECEIVE,
+	WAIT_EVENT_MQ_SEND,
+	WAIT_EVENT_PARALLEL_FINISH,
+	WAIT_EVENT_SAFE_SNAPSHOT,
+	WAIT_EVENT_SYNC_REP
+} WaitEventIPC;
+
+/* ----------
+ * Wait Events - Timeout
+ *
+ * Use this category when a process is waiting for a timeout to expire.
+ * ----------
+ */
+typedef enum
+{
+	WAIT_EVENT_BASE_BACKUP_THROTTLE = WAIT_TIMEOUT,
+	WAIT_EVENT_PG_SLEEP,
+	WAIT_EVENT_RECOVERY_APPLY_DELAY
+} WaitEventTimeout;
 
 /* ----------
  * Command type for progress reporting purposes
@@ -1018,23 +1094,18 @@ extern void pgstat_initstats(Relation rel);
  * ----------
  */
 static inline void
-pgstat_report_wait_start(uint8 classId, uint16 eventId)
+pgstat_report_wait_start(uint32 wait_event_info)
 {
 	volatile PGPROC *proc = MyProc;
-	uint32		wait_event_val;
 
 	if (!pgstat_track_activities || !proc)
 		return;
 
-	wait_event_val = classId;
-	wait_event_val <<= 24;
-	wait_event_val |= eventId;
-
 	/*
 	 * Since this is a four-byte field which is always read and written as
 	 * four-bytes, updates are atomic.
 	 */
-	proc->wait_event_info = wait_event_val;
+	proc->wait_event_info = wait_event_info;
 }
 
 /* ----------
diff --git a/src/include/storage/latch.h b/src/include/storage/latch.h
index 5179ecc..e96e88f 100644
--- a/src/include/storage/latch.h
+++ b/src/include/storage/latch.h
@@ -155,10 +155,13 @@ extern int AddWaitEventToSet(WaitEventSet *set, uint32 events, pgsocket fd,
 				  Latch *latch, void *user_data);
 extern void ModifyWaitEvent(WaitEventSet *set, int pos, uint32 events, Latch *latch);
 
-extern int	WaitEventSetWait(WaitEventSet *set, long timeout, WaitEvent *occurred_events, int nevents);
-extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout);
+extern int WaitEventSetWait(WaitEventSet *set, long timeout,
+				 WaitEvent *occurred_events, int nevents,
+				 uint32 wait_event_info);
+extern int WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+		  uint32 wait_event_info);
 extern int WaitLatchOrSocket(volatile Latch *latch, int wakeEvents,
-				  pgsocket sock, long timeout);
+				  pgsocket sock, long timeout, uint32 wait_event_info);
 
 /*
  * Unix implementation uses SIGUSR1 for inter-process signaling.
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index 18931eb..9a2d869 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -184,7 +184,7 @@ extern Size LWLockShmemSize(void);
 extern void CreateLWLocks(void);
 extern void InitLWLockAccess(void);
 
-extern const char *GetLWLockIdentifier(uint8 classId, uint16 eventId);
+extern const char *GetLWLockIdentifier(uint32 classId, uint16 eventId);
 
 /*
  * Extensions (or core code) can obtain an LWLocks by calling
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index f576f05..7dc8dac 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -291,7 +291,7 @@ extern void CheckDeadLockAlert(void);
 extern bool IsWaitingForLock(void);
 extern void LockErrorCleanup(void);
 
-extern void ProcWaitForSignal(void);
+extern void ProcWaitForSignal(uint32 wait_event_info);
 extern void ProcSendSignal(int pid);
 
 extern void BecomeLockGroupLeader(void);

diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 8ca1c1c..9badfe6 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -17,6 +17,7 @@
 #include "access/xact.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "storage/latch.h"
 #include "utils/hsearch.h"
 #include "utils/memutils.h"
@@ -496,7 +497,7 @@ pgfdw_get_result(PGconn *conn, const char *query)
 			wc = WaitLatchOrSocket(MyLatch,
 								   WL_LATCH_SET | WL_SOCKET_READABLE,
 								   PQsocket(conn),
-								   -1L);
+								   -1L, WAIT_EXTENSION);
 			ResetLatch(MyLatch);
 
 			CHECK_FOR_INTERRUPTS();
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index f400785..3de489e 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -679,6 +679,42 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
           buffer in question.
          </para>
         </listitem>
+        <listitem>
+         <para>
+          <literal>Activity</>: The server process is idle.  This is used by
+          system processes waiting for activity in their main processing loop.
+          <literal>wait_event</> will identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Extension</>: The server process is waiting for activity
+          in an extension module.  This category is useful for modules to
+          track custom waiting points.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Client</>: The server process is waiting for some activity
+          on a socket from user applications, and that the server expects
+          something to happen that is independent from its internal processes.
+          <literal>wait_event</> will identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>IPC</>: The server process is waiting for some activity
+          from another process in the server.  <literal>wait_event</> will
+          identify the specific wait point.
+         </para>
+        </listitem>
+        <listitem>
+         <para>
+          <literal>Timeout</>: The server process is waiting for a timeout
+          to expire.  <literal>wait_event</> will identify the specific wait
+          point.
+         </para>
+        </listitem>
        </itemizedlist>
       </entry>
      </row>
@@ -1085,6 +1121,139 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
          <entry><literal>BufferPin</></entry>
          <entry>Waiting to acquire a pin on a buffer.</entry>
         </row>
+        <row>
+         <entry morerows="11"><literal>Activity</></entry>
+         <entry><literal>ArchiverMain</></entry>
+         <entry>Waiting in main loop of the archiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>AutoVacuumMain</></entry>
+         <entry>Waiting in main loop of autovacuum launcher process.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterHibernate</></entry>
+         <entry>Waiting in background writer process, hibernating.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWriterMain</></entry>
+         <entry>Waiting in main loop of background writer process background worker.</entry>
+        </row>
+        <row>
+         <entry><literal>CheckpointerMain</></entry>
+         <entry>Waiting in main loop of checkpointer process.</entry>
+        </row>
+        <row>
+         <entry><literal>PgStatMain</></entry>
+         <entry>Waiting in main loop of the statistics collector process.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalAll</></entry>
+         <entry>Waiting for WAL from any kind of source (local, archive or stream) at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryWalStream</></entry>
+         <entry>Waiting for WAL from a stream at recovery.</entry>
+        </row>
+        <row>
+         <entry><literal>SysLoggerMain</></entry>
+         <entry>Waiting in main loop of syslogger process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverMain</></entry>
+         <entry>Waiting in main loop of WAL receiver process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderMain</></entry>
+         <entry>Waiting in main loop of WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalWriterMain</></entry>
+         <entry>Waiting in main loop of WAL writer process.</entry>
+        </row>
+        <row>
+         <entry morerows="5"><literal>Client</></entry>
+         <entry><literal>ClientRead</></entry>
+         <entry>Waiting to read data from the client.</entry>
+        </row>
+        <row>
+         <entry><literal>ClientWrite</></entry>
+         <entry>Waiting to write data from the client.</entry>
+        </row>
+        <row>
+         <entry><literal>SSLOpenServer</></entry>
+         <entry>Waiting for SSL while attempting connection.</entry>
+        </row>
+        <row>
+         <entry><literal>WalReceiverWaitStart</></entry>
+         <entry>Waiting for startup process to send initial data for streaming replication.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWaitForWAL</></entry>
+         <entry>Waiting for WAL to be flushed in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>WalSenderWriteData</></entry>
+         <entry>Waiting for any activity when processing replies from WAL receiver in WAL sender process.</entry>
+        </row>
+        <row>
+         <entry><literal>Extension</></entry>
+         <entry><literal>Extension</></entry>
+         <entry>Waiting in an extension.</entry>
+        </row>
+        <row>
+         <entry morerows="9"><literal>IPC</></entry>
+         <entry><literal>BgWorkerShutdown</></entry>
+         <entry>Waiting for background worker to shut down.</entry>
+        </row>
+        <row>
+         <entry><literal>BgWorkerStartup</></entry>
+         <entry>Waiting for background worker to start up.</entry>
+        </row>
+        <row>
+         <entry><literal>ExecuteGather</></entry>
+         <entry>Waiting for activity from child process when executing <literal>Gather</> node.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueInternal</></entry>
+         <entry>Waiting for other process to be attached in shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueuePutMessage</></entry>
+         <entry>Waiting to write a protoocol message to a shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueReceive</></entry>
+         <entry>Waiting to receive bytes from a shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>MessageQueueSend</></entry>
+         <entry>Waiting to send bytes to a shared message queue.</entry>
+        </row>
+        <row>
+         <entry><literal>ParallelFinish</></entry>
+         <entry>Waiting for parallel workers to finish computing.</entry>
+        </row>
+        <row>
+         <entry><literal>SafeSnapshot</></entry>
+         <entry>Waiting for a snapshot for a <literal>READ ONLY DEFERRABLE</> transaction.</entry>
+        </row>
+        <row>
+         <entry><literal>SyncRep</></entry>
+         <entry>Waiting for confirmation from remote server during synchronous replication.</entry>
+        </row>
+        <row>
+         <entry morerows="2"><literal>Timeout</></entry>
+         <entry><literal>BaseBackupThrottle</></entry>
+         <entry>Waiting during base backup when throttling activity.</entry>
+        </row>
+        <row>
+         <entry><literal>PgSleep</></entry>
+         <entry>Waiting in process that called <function>pg_sleep</>.</entry>
+        </row>
+        <row>
+         <entry><literal>RecoveryApplyDelay</></entry>
+         <entry>Waiting to apply WAL at recovery because it is delayed.</entry>
+        </row>
       </tbody>
      </tgroup>
     </table>
diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c
index cde0ed3..59dc394 100644
--- a/src/backend/access/transam/parallel.c
+++ b/src/backend/access/transam/parallel.c
@@ -24,6 +24,7 @@
 #include "libpq/pqmq.h"
 #include "miscadmin.h"
 #include "optimizer/planmain.h"
+#include "pgstat.h"
 #include "storage/ipc.h"
 #include "storage/sinval.h"
 #include "storage/spin.h"
@@ -540,7 +541,8 @@ WaitForParallelWorkersToFinish(ParallelContext *pcxt)
 		if (!anyone_alive)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, -1,
+				  WAIT_EVENT_PARALLEL_FINISH);
 		ResetLatch(&MyProc->procLatch);
 	}
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index c1b9a97..08c87f9 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5827,7 +5827,8 @@ recoveryApplyDelay(XLogReaderState *record)
 
 		WaitLatch(&XLogCtl->recoveryWakeupLatch,
 				  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-				  secs * 1000L + microsecs / 1000);
+				  secs * 1000L + microsecs / 1000,
+				  WAIT_EVENT_RECOVERY_APPLY_DELAY);
 	}
 	return true;
 }
@@ -11387,7 +11388,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 
 						WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								  wait_time);
+								  wait_time, WAIT_EVENT_RECOVERY_WAL_STREAM);
 						ResetLatch(&XLogCtl->recoveryWakeupLatch);
 						now = GetCurrentTimestamp();
 					}
@@ -11550,7 +11551,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					 */
 					WaitLatch(&XLogCtl->recoveryWakeupLatch,
 							  WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							  5000L);
+							  5000L, WAIT_EVENT_RECOVERY_WAL_ALL);
 					ResetLatch(&XLogCtl->recoveryWakeupLatch);
 					break;
 				}
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 438d1b2..880ca62 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -38,6 +38,7 @@
 #include "executor/nodeSubplan.h"
 #include "executor/tqueue.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "utils/memutils.h"
 #include "utils/rel.h"
 
@@ -387,7 +388,7 @@ gather_readnext(GatherState *gatherstate)
 				return NULL;
 
 			/* Nothing to do except wait for developments. */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_EVENT_EXECUTE_GATHER);
 			ResetLatch(MyLatch);
 			nvisited = 0;
 		}
diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
index fedb02c..668f217 100644
--- a/src/backend/libpq/be-secure-openssl.c
+++ b/src/backend/libpq/be-secure-openssl.c
@@ -60,6 +60,7 @@
 
 #include "libpq/libpq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "storage/latch.h"
 #include "tcop/tcopprot.h"
 #include "utils/memutils.h"
@@ -419,7 +420,8 @@ aloop:
 				else
 					waitfor = WL_SOCKET_WRITEABLE;
 
-				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0);
+				WaitLatchOrSocket(MyLatch, waitfor, port->sock, 0,
+								  WAIT_EVENT_SSL_OPEN_SERVER);
 				goto aloop;
 			case SSL_ERROR_SYSCALL:
 				if (r < 0)
diff --git a/src/backend/libpq/be-secure.c b/src/backend/libpq/be-secure.c
index cdd07d5..b267507 100644
--- a/src/backend/libpq/be-secure.c
+++ b/src/backend/libpq/be-secure.c
@@ -33,6 +33,7 @@
 
 #include "libpq/libpq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "tcop/tcopprot.h"
 #include "utils/memutils.h"
 #include "storage/ipc.h"
@@ -146,7 +147,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 WAIT_EVENT_CLIENT_READ);
 
 		/*
 		 * If the postmaster has died, it's not safe to continue running,
@@ -247,7 +249,8 @@ retry:
 
 		ModifyWaitEvent(FeBeWaitSet, 0, waitfor, NULL);
 
-		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1);
+		WaitEventSetWait(FeBeWaitSet, -1 /* no timeout */ , &event, 1,
+						 WAIT_EVENT_CLIENT_WRITE);
 
 		/* See comments in secure_read. */
 		if (event.events & WL_POSTMASTER_DEATH)
diff --git a/src/backend/libpq/pqmq.c b/src/backend/libpq/pqmq.c
index bfe66c6..f93ccae 100644
--- a/src/backend/libpq/pqmq.c
+++ b/src/backend/libpq/pqmq.c
@@ -17,6 +17,7 @@
 #include "libpq/pqformat.h"
 #include "libpq/pqmq.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "tcop/tcopprot.h"
 #include "utils/builtins.h"
 
@@ -171,7 +172,8 @@ mq_putmessage(char msgtype, const char *s, size_t len)
 		if (result != SHM_MQ_WOULD_BLOCK)
 			break;
 
-		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0);
+		WaitLatch(&MyProc->procLatch, WL_LATCH_SET, 0,
+				  WAIT_EVENT_MQ_PUT_MESSAGE);
 		ResetLatch(&MyProc->procLatch);
 		CHECK_FOR_INTERRUPTS();
 	}
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 1a92ca1..e3a6911 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -598,7 +598,8 @@ AutoVacLauncherMain(int argc, char *argv[])
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L));
+					   (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L),
+					   WAIT_EVENT_AUTOVACUUM_MAIN);
 
 		ResetLatch(MyLatch);
 
diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c
index 699c934..028a9ee 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -18,6 +18,7 @@
 #include "libpq/pqsignal.h"
 #include "postmaster/bgworker_internals.h"
 #include "postmaster/postmaster.h"
+#include "pgstat.h"
 #include "storage/barrier.h"
 #include "storage/dsm.h"
 #include "storage/ipc.h"
@@ -969,7 +970,8 @@ WaitForBackgroundWorkerStartup(BackgroundWorkerHandle *handle, pid_t *pidp)
 			break;
 
 		rc = WaitLatch(MyLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   WAIT_EVENT_BGWORKER_STARTUP);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
@@ -1008,7 +1010,8 @@ WaitForBackgroundWorkerShutdown(BackgroundWorkerHandle *handle)
 			break;
 
 		rc = WaitLatch(&MyProc->procLatch,
-					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+					   WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+					   WAIT_EVENT_BGWORKER_SHUTDOWN);
 
 		if (rc & WL_POSTMASTER_DEATH)
 		{
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index 1002034..c3f3356 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -345,7 +345,7 @@ BackgroundWriterMain(void)
 		 */
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   BgWriterDelay /* ms */ );
+					   BgWriterDelay /* ms */, WAIT_EVENT_BGWRITER_MAIN);
 
 		/*
 		 * If no latch event and BgBufferSync says nothing's happening, extend
@@ -372,7 +372,8 @@ BackgroundWriterMain(void)
 			/* Sleep ... */
 			rc = WaitLatch(MyLatch,
 						   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-						   BgWriterDelay * HIBERNATE_FACTOR);
+						   BgWriterDelay * HIBERNATE_FACTOR,
+						   WAIT_EVENT_BGWRITER_HIBERNATE);
 			/* Reset the notification request in case we timed out */
 			StrategyNotifyBgWriter(-1);
 		}
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index d702a48..397267c 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -556,7 +556,8 @@ CheckpointerMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout * 1000L /* convert to ms */ );
+					   cur_timeout * 1000L /* convert to ms */,
+					   WAIT_EVENT_CHECKPOINTER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 1aa6466..62783d9 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -390,7 +390,8 @@ pgarch_MainLoop(void)
 
 				rc = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-							   timeout * 1000L);
+							   timeout * 1000L,
+							   WAIT_EVENT_ARCHIVER_MAIN);
 				if (rc & WL_TIMEOUT)
 					wakened = true;
 			}
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 96578dc..8c9d06f 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -276,6 +276,11 @@ static PgStat_TableStatus *get_tabstat_entry(Oid rel_id, bool isshared);
 
 static void pgstat_setup_memcxt(void);
 
+static const char *pgstat_get_wait_activity(WaitEventActivity w);
+static const char *pgstat_get_wait_client(WaitEventClient w);
+static const char *pgstat_get_wait_ipc(WaitEventIPC w);
+static const char *pgstat_get_wait_timeout(WaitEventTimeout w);
+
 static void pgstat_setheader(PgStat_MsgHdr *hdr, StatMsgType mtype);
 static void pgstat_send(void *msg, int len);
 
@@ -3131,15 +3136,14 @@ pgstat_read_current_status(void)
 const char *
 pgstat_get_wait_event_type(uint32 wait_event_info)
 {
-	uint8		classId;
+	uint32		classId;
 	const char *event_type;
 
 	/* report process as not waiting. */
 	if (wait_event_info == 0)
 		return NULL;
 
-	wait_event_info = wait_event_info >> 24;
-	classId = wait_event_info & 0XFF;
+	classId = wait_event_info & 0xFF000000;
 
 	switch (classId)
 	{
@@ -3155,6 +3159,21 @@ pgstat_get_wait_event_type(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_type = "BufferPin";
 			break;
+		case WAIT_ACTIVITY:
+			event_type = "Activity";
+			break;
+		case WAIT_CLIENT:
+			event_type = "Client";
+			break;
+		case WAIT_EXTENSION:
+			event_type = "Extension";
+			break;
+		case WAIT_IPC:
+			event_type = "IPC";
+			break;
+		case WAIT_TIMEOUT:
+			event_type = "Timeout";
+			break;
 		default:
 			event_type = "???";
 			break;
@@ -3172,7 +3191,7 @@ pgstat_get_wait_event_type(uint32 wait_event_info)
 const char *
 pgstat_get_wait_event(uint32 wait_event_info)
 {
-	uint8		classId;
+	uint32		classId;
 	uint16		eventId;
 	const char *event_name;
 
@@ -3180,9 +3199,8 @@ pgstat_get_wait_event(uint32 wait_event_info)
 	if (wait_event_info == 0)
 		return NULL;
 
-	eventId = wait_event_info & ((1 << 24) - 1);
-	wait_event_info = wait_event_info >> 24;
-	classId = wait_event_info & 0XFF;
+	classId = wait_event_info & 0xFF000000;
+	eventId = wait_event_info & 0x0000FFFF;
 
 	switch (classId)
 	{
@@ -3196,6 +3214,37 @@ pgstat_get_wait_event(uint32 wait_event_info)
 		case WAIT_BUFFER_PIN:
 			event_name = "BufferPin";
 			break;
+		case WAIT_ACTIVITY:
+			{
+				WaitEventActivity	w = (WaitEventActivity) wait_event_info;
+
+				event_name = pgstat_get_wait_activity(w);
+				break;
+			}
+		case WAIT_CLIENT:
+			{
+				WaitEventClient	w = (WaitEventClient) wait_event_info;
+
+				event_name = pgstat_get_wait_client(w);
+				break;
+			}
+		case WAIT_EXTENSION:
+			event_name = "Extension";
+			break;
+		case WAIT_IPC:
+			{
+				WaitEventIPC	w = (WaitEventIPC) wait_event_info;
+
+				event_name = pgstat_get_wait_ipc(w);
+				break;
+			}
+		case WAIT_TIMEOUT:
+			{
+				WaitEventTimeout	w = (WaitEventTimeout) wait_event_info;
+
+				event_name = pgstat_get_wait_timeout(w);
+				break;
+			}
 		default:
 			event_name = "unknown wait event";
 			break;
@@ -3205,6 +3254,175 @@ pgstat_get_wait_event(uint32 wait_event_info)
 }
 
 /* ----------
+ * pgstat_get_wait_activity() -
+ *
+ * Convert WaitEventActivity to string.
+ * ----------
+ */
+static const char *
+pgstat_get_wait_activity(WaitEventActivity w)
+{
+	const char *event_name = "unknown wait event";
+
+	switch (w)
+	{
+		case WAIT_EVENT_ARCHIVER_MAIN:
+			event_name = "ArchiverMain";
+			break;
+		case WAIT_EVENT_AUTOVACUUM_MAIN:
+			event_name = "AutoVacuumMain";
+			break;
+		case WAIT_EVENT_BGWRITER_HIBERNATE:
+			event_name = "BgWriterHibernate";
+			break;
+		case WAIT_EVENT_BGWRITER_MAIN:
+			event_name = "BgWriterMain";
+			break;
+		case WAIT_EVENT_CHECKPOINTER_MAIN:
+			event_name = "CheckpointerMain";
+			break;
+		case WAIT_EVENT_PGSTAT_MAIN:
+			event_name = "PgStatMain";
+			break;
+		case WAIT_EVENT_RECOVERY_WAL_ALL:
+			event_name = "RecoveryWalAll";
+			break;
+		case WAIT_EVENT_RECOVERY_WAL_STREAM:
+			event_name = "RecoveryWalStream";
+			break;
+		case WAIT_EVENT_SYSLOGGER_MAIN:
+			event_name = "SysLoggerMain";
+			break;
+		case WAIT_EVENT_WAL_RECEIVER_MAIN:
+			event_name = "WalReceiverMain";
+			break;
+		case WAIT_EVENT_WAL_SENDER_MAIN:
+			event_name = "WalSenderMain";
+			break;
+		case WAIT_EVENT_WAL_WRITER_MAIN:
+			event_name = "WalWriterMain";
+			break;
+		/* no default case, so that compiler will warn */
+	}
+
+	return event_name;
+}
+
+/* ----------
+ * pgstat_get_wait_client() -
+ *
+ * Convert WaitEventClient to string.
+ * ----------
+ */
+static const char *
+pgstat_get_wait_client(WaitEventClient w)
+{
+	const char *event_name = "unknown wait event";
+
+	switch (w)
+	{
+		case WAIT_EVENT_CLIENT_READ:
+			event_name = "ClientRead";
+			break;
+		case WAIT_EVENT_CLIENT_WRITE:
+			event_name = "ClientWrite";
+			break;
+		case WAIT_EVENT_SSL_OPEN_SERVER:
+			event_name = "SSLOpenServer";
+			break;
+		case WAIT_EVENT_WAL_RECEIVER_WAIT_START:
+			event_name = "WalReceiverWaitStart";
+			break;
+		case WAIT_EVENT_WAL_SENDER_WAIT_WAL:
+			event_name = "WalSenderWaitForWAL";
+			break;
+		case WAIT_EVENT_WAL_SENDER_WRITE_DATA:
+			event_name = "WalSenderWriteData";
+			break;
+		/* no default case, so that compiler will warn */
+	}
+
+	return event_name;
+}
+
+/* ----------
+ * pgstat_get_wait_ipc() -
+ *
+ * Convert WaitEventIPC to string.
+ * ----------
+ */
+static const char *
+pgstat_get_wait_ipc(WaitEventIPC w)
+{
+	const char *event_name = "unknown wait event";
+
+	switch (w)
+	{
+		case WAIT_EVENT_BGWORKER_SHUTDOWN:
+			event_name = "BgWorkerShutdown";
+			break;
+		case WAIT_EVENT_BGWORKER_STARTUP:
+			event_name = "BgWorkerStartup";
+			break;
+		case WAIT_EVENT_EXECUTE_GATHER:
+			event_name = "ExecuteGather";
+			break;
+		case WAIT_EVENT_MQ_INTERNAL:
+			event_name = "MessageQueueInternal";
+			break;
+		case WAIT_EVENT_MQ_PUT_MESSAGE:
+			event_name = "MessageQueuePutMessage";
+			break;
+		case WAIT_EVENT_MQ_RECEIVE:
+			event_name = "MessageQueueReceive";
+			break;
+		case WAIT_EVENT_MQ_SEND:
+			event_name = "MessageQueueSend";
+			break;
+		case WAIT_EVENT_PARALLEL_FINISH:
+			event_name = "ParallelFinish";
+			break;
+		case WAIT_EVENT_SAFE_SNAPSHOT:
+			event_name = "SafeSnapshot";
+			break;
+		case WAIT_EVENT_SYNC_REP:
+			event_name = "SyncRep";
+			break;
+		/* no default case, so that compiler will warn */
+	}
+
+	return event_name;
+}
+
+/* ----------
+ * pgstat_get_wait_timeout() -
+ *
+ * Convert WaitEventTimeout to string.
+ * ----------
+ */
+static const char *
+pgstat_get_wait_timeout(WaitEventTimeout w)
+{
+	const char *event_name = "unknown wait event";
+
+	switch (w)
+	{
+		case WAIT_EVENT_BASE_BACKUP_THROTTLE:
+			event_name = "BaseBackupThrottle";
+			break;
+		case WAIT_EVENT_PG_SLEEP:
+			event_name = "PgSleep";
+			break;
+		case WAIT_EVENT_RECOVERY_APPLY_DELAY:
+			event_name = "RecoveryApplyDelay";
+			break;
+		/* no default case, so that compiler will warn */
+	}
+
+	return event_name;
+}
+
+/* ----------
  * pgstat_get_backend_current_activity() -
  *
  *	Return a string representing the current activity of the backend with
@@ -3684,8 +3902,8 @@ PgstatCollectorMain(int argc, char *argv[])
 #ifndef WIN32
 		wr = WaitLatchOrSocket(MyLatch,
 					 WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE,
-							   pgStatSock,
-							   -1L);
+							   pgStatSock, -1L,
+							   WAIT_EVENT_PGSTAT_MAIN);
 #else
 
 		/*
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index e7e488a..af71367 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -35,6 +35,7 @@
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "nodes/pg_list.h"
+#include "pgstat.h"
 #include "pgtime.h"
 #include "postmaster/fork_process.h"
 #include "postmaster/postmaster.h"
@@ -424,7 +425,8 @@ SysLoggerMain(int argc, char *argv[])
 		rc = WaitLatchOrSocket(MyLatch,
 							   WL_LATCH_SET | WL_SOCKET_READABLE | cur_flags,
 							   syslogPipe[0],
-							   cur_timeout);
+							   cur_timeout,
+							   WAIT_EVENT_SYSLOGGER_MAIN);
 
 		if (rc & WL_SOCKET_READABLE)
 		{
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index 11ec56a..67dcff6 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -290,7 +290,8 @@ WalWriterMain(void)
 
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-					   cur_timeout);
+					   cur_timeout,
+					   WAIT_EVENT_WAL_WRITER_MAIN);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index 1eabaef..fa75930 100644
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -1364,7 +1364,8 @@ throttle(size_t increment)
 		 */
 		wait_result = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
-								(long) (sleep / 1000));
+								(long) (sleep / 1000),
+								WAIT_EVENT_BASE_BACKUP_THROTTLE);
 
 		if (wait_result & WL_LATCH_SET)
 			CHECK_FOR_INTERRUPTS();
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index b442d06..ac29f56 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -61,6 +61,7 @@
 
 #include "access/xact.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "replication/syncrep.h"
 #include "replication/walsender.h"
 #include "replication/walsender_private.h"
@@ -258,7 +259,8 @@ SyncRepWaitForLSN(XLogRecPtr lsn, bool commit)
 		 * Wait on latch.  Any condition that should wake us up will set the
 		 * latch, so no need for timeout.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1);
+		WaitLatch(MyLatch, WL_LATCH_SET | WL_POSTMASTER_DEATH, -1,
+				  WAIT_EVENT_SYNC_REP);
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 413ee3a..eed6eff 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -55,6 +55,7 @@
 #include "libpq/pqformat.h"
 #include "libpq/pqsignal.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "replication/walreceiver.h"
 #include "replication/walsender.h"
 #include "storage/ipc.h"
@@ -486,7 +487,8 @@ WalReceiverMain(void)
 								   WL_POSTMASTER_DEATH | WL_SOCKET_READABLE |
 									   WL_TIMEOUT | WL_LATCH_SET,
 									   wait_fd,
-									   NAPTIME_PER_CYCLE);
+									   NAPTIME_PER_CYCLE,
+									   WAIT_EVENT_WAL_RECEIVER_MAIN);
 				if (rc & WL_LATCH_SET)
 				{
 					ResetLatch(&walrcv->latch);
@@ -685,7 +687,8 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 		}
 		SpinLockRelease(&walrcv->mutex);
 
-		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0);
+		WaitLatch(&walrcv->latch, WL_LATCH_SET | WL_POSTMASTER_DEATH, 0,
+				  WAIT_EVENT_WAL_RECEIVER_WAIT_START);
 	}
 
 	if (update_process_title)
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index c7743da..0f3ced2 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -1146,7 +1146,8 @@ WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid,
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  WAIT_EVENT_WAL_SENDER_WRITE_DATA);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1272,7 +1273,8 @@ WalSndWaitForWal(XLogRecPtr loc)
 
 		/* Sleep until something happens or we time out */
 		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime);
+						  MyProcPort->sock, sleeptime,
+						  WAIT_EVENT_WAL_SENDER_WAIT_WAL);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */
@@ -1924,7 +1926,8 @@ WalSndLoop(WalSndSendDataCallback send_data)
 
 			/* Sleep until something happens or we time out */
 			WaitLatchOrSocket(MyLatch, wakeEvents,
-							  MyProcPort->sock, sleeptime);
+							  MyProcPort->sock, sleeptime,
+							  WAIT_EVENT_WAL_SENDER_MAIN);
 		}
 	}
 	return;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 90804a3..91dc24c 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -3635,9 +3635,6 @@ LockBufferForCleanup(Buffer buffer)
 		UnlockBufHdr(bufHdr, buf_state);
 		LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
 
-		/* Report the wait */
-		pgstat_report_wait_start(WAIT_BUFFER_PIN, 0);
-
 		/* Wait to be signaled by UnpinBuffer() */
 		if (InHotStandby)
 		{
@@ -3649,9 +3646,7 @@ LockBufferForCleanup(Buffer buffer)
 			SetStartupBufferPinWaitBufId(-1);
 		}
 		else
-			ProcWaitForSignal();
-
-		pgstat_report_wait_end();
+			ProcWaitForSignal(WAIT_BUFFER_PIN);
 
 		/*
 		 * Remove flag marking us as waiter. Normally this will not be set
diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c
index 9def8a1..8488f94 100644
--- a/src/backend/storage/ipc/latch.c
+++ b/src/backend/storage/ipc/latch.c
@@ -55,6 +55,7 @@
 #endif
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "portability/instr_time.h"
 #include "postmaster/postmaster.h"
 #include "storage/barrier.h"
@@ -297,9 +298,11 @@ DisownLatch(volatile Latch *latch)
  * we return all of them in one call, but we will return at least one.
  */
 int
-WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
+WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+		  uint32 wait_event_info)
 {
-	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout);
+	return WaitLatchOrSocket(latch, wakeEvents, PGINVALID_SOCKET, timeout,
+							 wait_event_info);
 }
 
 /*
@@ -316,7 +319,7 @@ WaitLatch(volatile Latch *latch, int wakeEvents, long timeout)
  */
 int
 WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
-				  long timeout)
+				  long timeout, uint32 wait_event_info)
 {
 	int			ret = 0;
 	int			rc;
@@ -344,7 +347,7 @@ WaitLatchOrSocket(volatile Latch *latch, int wakeEvents, pgsocket sock,
 		AddWaitEventToSet(set, ev, sock, NULL, NULL);
 	}
 
-	rc = WaitEventSetWait(set, timeout, &event, 1);
+	rc = WaitEventSetWait(set, timeout, &event, 1, wait_event_info);
 
 	if (rc == 0)
 		ret |= WL_TIMEOUT;
@@ -863,7 +866,8 @@ WaitEventAdjustWin32(WaitEventSet *set, WaitEvent *event)
  */
 int
 WaitEventSetWait(WaitEventSet *set, long timeout,
-				 WaitEvent *occurred_events, int nevents)
+				 WaitEvent *occurred_events, int nevents,
+				 uint32 wait_event_info)
 {
 	int			returned_events = 0;
 	instr_time	start_time;
@@ -883,6 +887,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 		cur_timeout = timeout;
 	}
 
+	pgstat_report_wait_start(wait_event_info);
+
 #ifndef WIN32
 	waiting = true;
 #else
@@ -960,6 +966,8 @@ WaitEventSetWait(WaitEventSet *set, long timeout,
 	waiting = false;
 #endif
 
+	pgstat_report_wait_end();
+
 	return returned_events;
 }
 
diff --git a/src/backend/storage/ipc/shm_mq.c b/src/backend/storage/ipc/shm_mq.c
index 5b32782..bfb6703 100644
--- a/src/backend/storage/ipc/shm_mq.c
+++ b/src/backend/storage/ipc/shm_mq.c
@@ -19,6 +19,7 @@
 #include "postgres.h"
 
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/bgworker.h"
 #include "storage/procsignal.h"
 #include "storage/shm_mq.h"
@@ -894,7 +895,7 @@ shm_mq_send_bytes(shm_mq_handle *mqh, Size nbytes, const void *data,
 			 * at top of loop, because setting an already-set latch is much
 			 * cheaper than setting one that has been reset.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_EVENT_MQ_SEND);
 
 			/* Reset the latch so we don't spin. */
 			ResetLatch(MyLatch);
@@ -991,7 +992,7 @@ shm_mq_receive_bytes(shm_mq *mq, Size bytes_needed, bool nowait,
 		 * loop, because setting an already-set latch is much cheaper than
 		 * setting one that has been reset.
 		 */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_EVENT_MQ_RECEIVE);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
@@ -1090,7 +1091,7 @@ shm_mq_wait_internal(volatile shm_mq *mq, PGPROC *volatile * ptr,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_EVENT_MQ_INTERNAL);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/backend/storage/ipc/standby.c b/src/backend/storage/ipc/standby.c
index 547f1a8..fb887b3 100644
--- a/src/backend/storage/ipc/standby.c
+++ b/src/backend/storage/ipc/standby.c
@@ -22,6 +22,7 @@
 #include "access/xlog.h"
 #include "access/xloginsert.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "storage/bufmgr.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
@@ -389,7 +390,7 @@ ResolveRecoveryConflictWithLock(LOCKTAG locktag)
 	}
 
 	/* Wait to be signaled by the release of the Relation Lock */
-	ProcWaitForSignal();
+	ProcWaitForSignal(WAIT_LOCK | locktag.locktag_type);
 
 	/*
 	 * Clear any timeout requests established above.  We assume here that the
@@ -469,7 +470,7 @@ ResolveRecoveryConflictWithBufferPin(void)
 	}
 
 	/* Wait to be signaled by UnpinBuffer() */
-	ProcWaitForSignal();
+	ProcWaitForSignal(WAIT_BUFFER_PIN);
 
 	/*
 	 * Clear any timeout requests established above.  We assume here that the
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index dba3809..71a4dd4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -1676,7 +1676,6 @@ WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
 		set_ps_display(new_status, false);
 		new_status[len] = '\0'; /* truncate off " waiting" */
 	}
-	pgstat_report_wait_start(WAIT_LOCK, locallock->tag.lock.locktag_type);
 
 	awaitedLock = locallock;
 	awaitedOwner = owner;
@@ -1724,7 +1723,6 @@ WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
 		/* In this path, awaitedLock remains set until LockErrorCleanup */
 
 		/* Report change to non-waiting status */
-		pgstat_report_wait_end();
 		if (update_process_title)
 		{
 			set_ps_display(new_status, false);
@@ -1739,7 +1737,6 @@ WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
 	awaitedLock = NULL;
 
 	/* Report change to non-waiting status */
-	pgstat_report_wait_end();
 	if (update_process_title)
 	{
 		set_ps_display(new_status, false);
diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c
index 9d08de7..a90b54a 100644
--- a/src/backend/storage/lmgr/lwlock.c
+++ b/src/backend/storage/lmgr/lwlock.c
@@ -732,9 +732,9 @@ LWLockReportWaitStart(LWLock *lock)
 	int			lockId = T_ID(lock);
 
 	if (lock->tranche == 0)
-		pgstat_report_wait_start(WAIT_LWLOCK_NAMED, (uint16) lockId);
+		pgstat_report_wait_start(WAIT_LWLOCK_NAMED | (uint16) lockId);
 	else
-		pgstat_report_wait_start(WAIT_LWLOCK_TRANCHE, lock->tranche);
+		pgstat_report_wait_start(WAIT_LWLOCK_TRANCHE | lock->tranche);
 }
 
 /*
@@ -750,7 +750,7 @@ LWLockReportWaitEnd(void)
  * Return an identifier for an LWLock based on the wait class and event.
  */
 const char *
-GetLWLockIdentifier(uint8 classId, uint16 eventId)
+GetLWLockIdentifier(uint32 classId, uint16 eventId)
 {
 	if (classId == WAIT_LWLOCK_NAMED)
 		return MainLWLockNames[eventId];
diff --git a/src/backend/storage/lmgr/predicate.c b/src/backend/storage/lmgr/predicate.c
index 4064b20..24ed21b 100644
--- a/src/backend/storage/lmgr/predicate.c
+++ b/src/backend/storage/lmgr/predicate.c
@@ -192,6 +192,7 @@
 #include "access/xact.h"
 #include "access/xlog.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "storage/bufmgr.h"
 #include "storage/predicate.h"
 #include "storage/predicate_internals.h"
@@ -1518,7 +1519,7 @@ GetSafeSnapshot(Snapshot origSnapshot)
 				 SxactIsROUnsafe(MySerializableXact)))
 		{
 			LWLockRelease(SerializableXactHashLock);
-			ProcWaitForSignal();
+			ProcWaitForSignal(WAIT_EVENT_SAFE_SNAPSHOT);
 			LWLockAcquire(SerializableXactHashLock, LW_EXCLUSIVE);
 		}
 		MySerializableXact->flags &= ~SXACT_FLAG_DEFERRABLE_WAITING;
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 33e7023..dd76094 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -39,6 +39,7 @@
 #include "access/twophase.h"
 #include "access/xact.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/autovacuum.h"
 #include "replication/slot.h"
 #include "replication/syncrep.h"
@@ -1212,7 +1213,8 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
 		}
 		else
 		{
-			WaitLatch(MyLatch, WL_LATCH_SET, 0);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0,
+					  WAIT_LOCK | locallock->tag.lock.locktag_type);
 			ResetLatch(MyLatch);
 			/* check for deadlocks first, as that's probably log-worthy */
 			if (got_deadlock_timeout)
@@ -1722,9 +1724,9 @@ CheckDeadLockAlert(void)
  * wait again if not.
  */
 void
-ProcWaitForSignal(void)
+ProcWaitForSignal(uint32 wait_event_info)
 {
-	WaitLatch(MyLatch, WL_LATCH_SET, 0);
+	WaitLatch(MyLatch, WL_LATCH_SET, 0, wait_event_info);
 	ResetLatch(MyLatch);
 	CHECK_FOR_INTERRUPTS();
 }
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 5e705e9..0da051a 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -29,6 +29,7 @@
 #include "common/keywords.h"
 #include "funcapi.h"
 #include "miscadmin.h"
+#include "pgstat.h"
 #include "parser/scansup.h"
 #include "postmaster/syslogger.h"
 #include "rewrite/rewriteHandler.h"
@@ -560,7 +561,8 @@ pg_sleep(PG_FUNCTION_ARGS)
 
 		(void) WaitLatch(MyLatch,
 						 WL_LATCH_SET | WL_TIMEOUT,
-						 delay_ms);
+						 delay_ms,
+						 WAIT_EVENT_PG_SLEEP);
 		ResetLatch(MyLatch);
 	}
 
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 0c98c59..b530c01 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -715,15 +715,91 @@ typedef enum BackendState
  * Wait Classes
  * ----------
  */
-typedef enum WaitClass
+#define WAIT_LWLOCK_NAMED			0x01000000U
+#define WAIT_LWLOCK_TRANCHE			0x02000000U
+#define WAIT_LOCK					0x03000000U
+#define WAIT_BUFFER_PIN				0x04000000U
+#define WAIT_ACTIVITY				0x05000000U
+#define WAIT_CLIENT					0x06000000U
+#define WAIT_EXTENSION				0x07000000U
+#define WAIT_IPC					0x08000000U
+#define WAIT_TIMEOUT				0x09000000U
+
+/* ----------
+ * Wait Events - Activity
+ *
+ * Use this category when a process is waiting because it has no work to do,
+ * unless the "Client" or "Timeout" category describes the situation better.
+ * Typically, this should only be used for background processes.
+ * ----------
+ */
+typedef enum
 {
-	WAIT_UNDEFINED,
-	WAIT_LWLOCK_NAMED,
-	WAIT_LWLOCK_TRANCHE,
-	WAIT_LOCK,
-	WAIT_BUFFER_PIN
-}	WaitClass;
+	WAIT_EVENT_ARCHIVER_MAIN = WAIT_ACTIVITY,
+	WAIT_EVENT_AUTOVACUUM_MAIN,
+	WAIT_EVENT_BGWRITER_HIBERNATE,
+	WAIT_EVENT_BGWRITER_MAIN,
+	WAIT_EVENT_CHECKPOINTER_MAIN,
+	WAIT_EVENT_PGSTAT_MAIN,
+	WAIT_EVENT_RECOVERY_WAL_ALL,
+	WAIT_EVENT_RECOVERY_WAL_STREAM,
+	WAIT_EVENT_SYSLOGGER_MAIN,
+	WAIT_EVENT_WAL_RECEIVER_MAIN,
+	WAIT_EVENT_WAL_SENDER_MAIN,
+	WAIT_EVENT_WAL_WRITER_MAIN,
+} WaitEventActivity;
 
+/* ----------
+ * Wait Events - Client
+ *
+ * Use this category when a process is waiting to send data to or receive data
+ * from the frontend process to which it is connected.  This is never used for
+ * a background process, which has no client connection.
+ * ----------
+ */
+typedef enum
+{
+	WAIT_EVENT_CLIENT_READ = WAIT_CLIENT,
+	WAIT_EVENT_CLIENT_WRITE,
+	WAIT_EVENT_SSL_OPEN_SERVER,
+	WAIT_EVENT_WAL_RECEIVER_WAIT_START,
+	WAIT_EVENT_WAL_SENDER_WAIT_WAL,
+	WAIT_EVENT_WAL_SENDER_WRITE_DATA,
+} WaitEventClient;
+
+/* ----------
+ * Wait Events - IPC
+ *
+ * Use this category when a process cannot complete the work it is doing because
+ * it is waiting for a notification from another process.
+ * ----------
+ */
+typedef enum
+{
+	WAIT_EVENT_BGWORKER_SHUTDOWN = WAIT_IPC,
+	WAIT_EVENT_BGWORKER_STARTUP,
+	WAIT_EVENT_EXECUTE_GATHER,
+	WAIT_EVENT_MQ_INTERNAL,
+	WAIT_EVENT_MQ_PUT_MESSAGE,
+	WAIT_EVENT_MQ_RECEIVE,
+	WAIT_EVENT_MQ_SEND,
+	WAIT_EVENT_PARALLEL_FINISH,
+	WAIT_EVENT_SAFE_SNAPSHOT,
+	WAIT_EVENT_SYNC_REP
+} WaitEventIPC;
+
+/* ----------
+ * Wait Events - Timeout
+ *
+ * Use this category when a process is waiting for a timeout to expire.
+ * ----------
+ */
+typedef enum
+{
+	WAIT_EVENT_BASE_BACKUP_THROTTLE = WAIT_TIMEOUT,
+	WAIT_EVENT_PG_SLEEP,
+	WAIT_EVENT_RECOVERY_APPLY_DELAY
+} WaitEventTimeout;
 
 /* ----------
  * Command type for progress reporting purposes
@@ -1018,23 +1094,18 @@ extern void pgstat_initstats(Relation rel);
  * ----------
  */
 static inline void
-pgstat_report_wait_start(uint8 classId, uint16 eventId)
+pgstat_report_wait_start(uint32 wait_event_info)
 {
 	volatile PGPROC *proc = MyProc;
-	uint32		wait_event_val;
 
 	if (!pgstat_track_activities || !proc)
 		return;
 
-	wait_event_val = classId;
-	wait_event_val <<= 24;
-	wait_event_val |= eventId;
-
 	/*
 	 * Since this is a four-byte field which is always read and written as
 	 * four-bytes, updates are atomic.
 	 */
-	proc->wait_event_info = wait_event_val;
+	proc->wait_event_info = wait_event_info;
 }
 
 /* ----------
diff --git a/src/include/storage/latch.h b/src/include/storage/latch.h
index 5179ecc..e96e88f 100644
--- a/src/include/storage/latch.h
+++ b/src/include/storage/latch.h
@@ -155,10 +155,13 @@ extern int AddWaitEventToSet(WaitEventSet *set, uint32 events, pgsocket fd,
 				  Latch *latch, void *user_data);
 extern void ModifyWaitEvent(WaitEventSet *set, int pos, uint32 events, Latch *latch);
 
-extern int	WaitEventSetWait(WaitEventSet *set, long timeout, WaitEvent *occurred_events, int nevents);
-extern int	WaitLatch(volatile Latch *latch, int wakeEvents, long timeout);
+extern int WaitEventSetWait(WaitEventSet *set, long timeout,
+				 WaitEvent *occurred_events, int nevents,
+				 uint32 wait_event_info);
+extern int WaitLatch(volatile Latch *latch, int wakeEvents, long timeout,
+		  uint32 wait_event_info);
 extern int WaitLatchOrSocket(volatile Latch *latch, int wakeEvents,
-				  pgsocket sock, long timeout);
+				  pgsocket sock, long timeout, uint32 wait_event_info);
 
 /*
  * Unix implementation uses SIGUSR1 for inter-process signaling.
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index 18931eb..9a2d869 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -184,7 +184,7 @@ extern Size LWLockShmemSize(void);
 extern void CreateLWLocks(void);
 extern void InitLWLockAccess(void);
 
-extern const char *GetLWLockIdentifier(uint8 classId, uint16 eventId);
+extern const char *GetLWLockIdentifier(uint32 classId, uint16 eventId);
 
 /*
  * Extensions (or core code) can obtain an LWLocks by calling
diff --git a/src/include/storage/proc.h b/src/include/storage/proc.h
index f576f05..7dc8dac 100644
--- a/src/include/storage/proc.h
+++ b/src/include/storage/proc.h
@@ -291,7 +291,7 @@ extern void CheckDeadLockAlert(void);
 extern bool IsWaitingForLock(void);
 extern void LockErrorCleanup(void);
 
-extern void ProcWaitForSignal(void);
+extern void ProcWaitForSignal(uint32 wait_event_info);
 extern void ProcSendSignal(int pid);
 
 extern void BecomeLockGroupLeader(void);

diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c
index 028a9ee..3a2929a 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -14,11 +14,11 @@
 
 #include <unistd.h>
 
-#include "miscadmin.h"
 #include "libpq/pqsignal.h"
+#include "miscadmin.h"
+#include "pgstat.h"
 #include "postmaster/bgworker_internals.h"
 #include "postmaster/postmaster.h"
-#include "pgstat.h"
 #include "storage/barrier.h"
 #include "storage/dsm.h"
 #include "storage/ipc.h"

diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 9badfe6..bcdddc2 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -497,7 +497,7 @@ pgfdw_get_result(PGconn *conn, const char *query)
 			wc = WaitLatchOrSocket(MyLatch,
 								   WL_LATCH_SET | WL_SOCKET_READABLE,
 								   PQsocket(conn),
-								   -1L, WAIT_EXTENSION);
+								   -1L, PG_WAIT_EXTENSION);
 			ResetLatch(MyLatch);
 
 			CHECK_FOR_INTERRUPTS();
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 5c6cb6b..a9efee8 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -3147,31 +3147,31 @@ pgstat_get_wait_event_type(uint32 wait_event_info)
 
 	switch (classId)
 	{
-		case WAIT_LWLOCK_NAMED:
+		case PG_WAIT_LWLOCK_NAMED:
 			event_type = "LWLockNamed";
 			break;
-		case WAIT_LWLOCK_TRANCHE:
+		case PG_WAIT_LWLOCK_TRANCHE:
 			event_type = "LWLockTranche";
 			break;
-		case WAIT_LOCK:
+		case PG_WAIT_LOCK:
 			event_type = "Lock";
 			break;
-		case WAIT_BUFFER_PIN:
+		case PG_WAIT_BUFFER_PIN:
 			event_type = "BufferPin";
 			break;
-		case WAIT_ACTIVITY:
+		case PG_WAIT_ACTIVITY:
 			event_type = "Activity";
 			break;
-		case WAIT_CLIENT:
+		case PG_WAIT_CLIENT:
 			event_type = "Client";
 			break;
-		case WAIT_EXTENSION:
+		case PG_WAIT_EXTENSION:
 			event_type = "Extension";
 			break;
-		case WAIT_IPC:
+		case PG_WAIT_IPC:
 			event_type = "IPC";
 			break;
-		case WAIT_TIMEOUT:
+		case PG_WAIT_TIMEOUT:
 			event_type = "Timeout";
 			break;
 		default:
@@ -3204,41 +3204,41 @@ pgstat_get_wait_event(uint32 wait_event_info)
 
 	switch (classId)
 	{
-		case WAIT_LWLOCK_NAMED:
-		case WAIT_LWLOCK_TRANCHE:
+		case PG_WAIT_LWLOCK_NAMED:
+		case PG_WAIT_LWLOCK_TRANCHE:
 			event_name = GetLWLockIdentifier(classId, eventId);
 			break;
-		case WAIT_LOCK:
+		case PG_WAIT_LOCK:
 			event_name = GetLockNameFromTagType(eventId);
 			break;
-		case WAIT_BUFFER_PIN:
+		case PG_WAIT_BUFFER_PIN:
 			event_name = "BufferPin";
 			break;
-		case WAIT_ACTIVITY:
+		case PG_WAIT_ACTIVITY:
 			{
 				WaitEventActivity	w = (WaitEventActivity) wait_event_info;
 
 				event_name = pgstat_get_wait_activity(w);
 				break;
 			}
-		case WAIT_CLIENT:
+		case PG_WAIT_CLIENT:
 			{
 				WaitEventClient	w = (WaitEventClient) wait_event_info;
 
 				event_name = pgstat_get_wait_client(w);
 				break;
 			}
-		case WAIT_EXTENSION:
+		case PG_WAIT_EXTENSION:
 			event_name = "Extension";
 			break;
-		case WAIT_IPC:
+		case PG_WAIT_IPC:
 			{
 				WaitEventIPC	w = (WaitEventIPC) wait_event_info;
 
 				event_name = pgstat_get_wait_ipc(w);
 				break;
 			}
-		case WAIT_TIMEOUT:
+		case PG_WAIT_TIMEOUT:
 			{
 				WaitEventTimeout	w = (WaitEventTimeout) wait_event_info;
 
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 91dc24c..2b63cd3 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -3646,7 +3646,7 @@ LockBufferForCleanup(Buffer buffer)
 			SetStartupBufferPinWaitBufId(-1);
 		}
 		else
-			ProcWaitForSignal(WAIT_BUFFER_PIN);
+			ProcWaitForSignal(PG_WAIT_BUFFER_PIN);
 
 		/*
 		 * Remove flag marking us as waiter. Normally this will not be set
diff --git a/src/backend/storage/ipc/standby.c b/src/backend/storage/ipc/standby.c
index fb887b3..875dcec 100644
--- a/src/backend/storage/ipc/standby.c
+++ b/src/backend/storage/ipc/standby.c
@@ -390,7 +390,7 @@ ResolveRecoveryConflictWithLock(LOCKTAG locktag)
 	}
 
 	/* Wait to be signaled by the release of the Relation Lock */
-	ProcWaitForSignal(WAIT_LOCK | locktag.locktag_type);
+	ProcWaitForSignal(PG_WAIT_LOCK | locktag.locktag_type);
 
 	/*
 	 * Clear any timeout requests established above.  We assume here that the
@@ -470,7 +470,7 @@ ResolveRecoveryConflictWithBufferPin(void)
 	}
 
 	/* Wait to be signaled by UnpinBuffer() */
-	ProcWaitForSignal(WAIT_BUFFER_PIN);
+	ProcWaitForSignal(PG_WAIT_BUFFER_PIN);
 
 	/*
 	 * Clear any timeout requests established above.  We assume here that the
diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c
index a90b54a..9c6862f 100644
--- a/src/backend/storage/lmgr/lwlock.c
+++ b/src/backend/storage/lmgr/lwlock.c
@@ -732,9 +732,9 @@ LWLockReportWaitStart(LWLock *lock)
 	int			lockId = T_ID(lock);
 
 	if (lock->tranche == 0)
-		pgstat_report_wait_start(WAIT_LWLOCK_NAMED | (uint16) lockId);
+		pgstat_report_wait_start(PG_WAIT_LWLOCK_NAMED | (uint16) lockId);
 	else
-		pgstat_report_wait_start(WAIT_LWLOCK_TRANCHE | lock->tranche);
+		pgstat_report_wait_start(PG_WAIT_LWLOCK_TRANCHE | lock->tranche);
 }
 
 /*
@@ -752,10 +752,10 @@ LWLockReportWaitEnd(void)
 const char *
 GetLWLockIdentifier(uint32 classId, uint16 eventId)
 {
-	if (classId == WAIT_LWLOCK_NAMED)
+	if (classId == PG_WAIT_LWLOCK_NAMED)
 		return MainLWLockNames[eventId];
 
-	Assert(classId == WAIT_LWLOCK_TRANCHE);
+	Assert(classId == PG_WAIT_LWLOCK_TRANCHE);
 
 	/*
 	 * It is quite possible that user has registered tranche in one of the
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index dd76094..b201631 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -1214,7 +1214,7 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
 		else
 		{
 			WaitLatch(MyLatch, WL_LATCH_SET, 0,
-					  WAIT_LOCK | locallock->tag.lock.locktag_type);
+					  PG_WAIT_LOCK | locallock->tag.lock.locktag_type);
 			ResetLatch(MyLatch);
 			/* check for deadlocks first, as that's probably log-worthy */
 			if (got_deadlock_timeout)
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 27be549..1c9bf13 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -715,15 +715,15 @@ typedef enum BackendState
  * Wait Classes
  * ----------
  */
-#define WAIT_LWLOCK_NAMED			0x01000000U
-#define WAIT_LWLOCK_TRANCHE			0x02000000U
-#define WAIT_LOCK					0x03000000U
-#define WAIT_BUFFER_PIN				0x04000000U
-#define WAIT_ACTIVITY				0x05000000U
-#define WAIT_CLIENT					0x06000000U
-#define WAIT_EXTENSION				0x07000000U
-#define WAIT_IPC					0x08000000U
-#define WAIT_TIMEOUT				0x09000000U
+#define PG_WAIT_LWLOCK_NAMED		0x01000000U
+#define PG_WAIT_LWLOCK_TRANCHE		0x02000000U
+#define PG_WAIT_LOCK				0x03000000U
+#define PG_WAIT_BUFFER_PIN			0x04000000U
+#define PG_WAIT_ACTIVITY			0x05000000U
+#define PG_WAIT_CLIENT				0x06000000U
+#define PG_WAIT_EXTENSION			0x07000000U
+#define PG_WAIT_IPC					0x08000000U
+#define PG_WAIT_TIMEOUT				0x09000000U
 
 /* ----------
  * Wait Events - Activity
@@ -735,7 +735,7 @@ typedef enum BackendState
  */
 typedef enum
 {
-	WAIT_EVENT_ARCHIVER_MAIN = WAIT_ACTIVITY,
+	WAIT_EVENT_ARCHIVER_MAIN = PG_WAIT_ACTIVITY,
 	WAIT_EVENT_AUTOVACUUM_MAIN,
 	WAIT_EVENT_BGWRITER_HIBERNATE,
 	WAIT_EVENT_BGWRITER_MAIN,
@@ -759,7 +759,7 @@ typedef enum
  */
 typedef enum
 {
-	WAIT_EVENT_CLIENT_READ = WAIT_CLIENT,
+	WAIT_EVENT_CLIENT_READ = PG_WAIT_CLIENT,
 	WAIT_EVENT_CLIENT_WRITE,
 	WAIT_EVENT_SSL_OPEN_SERVER,
 	WAIT_EVENT_WAL_RECEIVER_WAIT_START,
@@ -776,7 +776,7 @@ typedef enum
  */
 typedef enum
 {
-	WAIT_EVENT_BGWORKER_SHUTDOWN = WAIT_IPC,
+	WAIT_EVENT_BGWORKER_SHUTDOWN = PG_WAIT_IPC,
 	WAIT_EVENT_BGWORKER_STARTUP,
 	WAIT_EVENT_EXECUTE_GATHER,
 	WAIT_EVENT_MQ_INTERNAL,
@@ -796,7 +796,7 @@ typedef enum
  */
 typedef enum
 {
-	WAIT_EVENT_BASE_BACKUP_THROTTLE = WAIT_TIMEOUT,
+	WAIT_EVENT_BASE_BACKUP_THROTTLE = PG_WAIT_TIMEOUT,
 	WAIT_EVENT_PG_SLEEP,
 	WAIT_EVENT_RECOVERY_APPLY_DELAY
 } WaitEventTimeout;
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index cb86f3c..5cfffe4 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -280,7 +280,7 @@ wait_for_workers_to_become_ready(worker_state *wstate,
 		}
 
 		/* Wait to be signalled. */
-		WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_EXTENSION);
+		WaitLatch(MyLatch, WL_LATCH_SET, 0, PG_WAIT_EXTENSION);
 
 		/* Reset the latch so we don't spin. */
 		ResetLatch(MyLatch);
diff --git a/src/test/modules/test_shm_mq/test.c b/src/test/modules/test_shm_mq/test.c
index bf11137..b0f3d3d 100644
--- a/src/test/modules/test_shm_mq/test.c
+++ b/src/test/modules/test_shm_mq/test.c
@@ -231,7 +231,7 @@ test_shm_mq_pipelined(PG_FUNCTION_ARGS)
 			 * have read or written data and therefore there may now be work
 			 * for us to do.
 			 */
-			WaitLatch(MyLatch, WL_LATCH_SET, 0, WAIT_EXTENSION);
+			WaitLatch(MyLatch, WL_LATCH_SET, 0, PG_WAIT_EXTENSION);
 			ResetLatch(MyLatch);
 			CHECK_FOR_INTERRUPTS();
 		}
diff --git a/src/test/modules/worker_spi/worker_spi.c b/src/test/modules/worker_spi/worker_spi.c
index f8395bf..5f49549 100644
--- a/src/test/modules/worker_spi/worker_spi.c
+++ b/src/test/modules/worker_spi/worker_spi.c
@@ -228,7 +228,7 @@ worker_spi_main(Datum main_arg)
 		rc = WaitLatch(MyLatch,
 					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 					   worker_spi_naptime * 1000L,
-					   WAIT_EXTENSION);
+					   PG_WAIT_EXTENSION);
 		ResetLatch(MyLatch);
 
 		/* emergency bailout if postmaster has died */