From b20765526e5c4bb5a82734ad9977552ebf9dad2f Mon Sep 17 00:00:00 2001 From: Melanie Plageman Date: Mon, 24 Apr 2023 18:21:54 -0400 Subject: [PATCH v2] Add writeback to pg_stat_io --- doc/src/sgml/monitoring.sgml | 24 ++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 2 ++ src/backend/postmaster/bgwriter.c | 4 ++-- src/backend/storage/buffer/buf_init.c | 2 +- src/backend/storage/buffer/bufmgr.c | 12 ++++++++++-- src/backend/utils/adt/pgstatfuncs.c | 5 +++++ src/include/catalog/pg_proc.dat | 6 +++--- src/include/pgstat.h | 3 ++- src/include/storage/buf_internals.h | 4 +++- src/test/regress/expected/rules.out | 4 +++- 10 files changed, 55 insertions(+), 11 deletions(-) diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 99f7f95c39..62572327cf 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -3867,6 +3867,30 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i + + + + writebacks bigint + + + Number of writeback operations, each of the size specified in + op_bytes. + + + + + + + + writeback_time double precision + + + Time spent in writeback operations in milliseconds (if + is enabled, otherwise zero) + + + + diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index 48aacf66ee..d0c932ad0e 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -1131,6 +1131,8 @@ SELECT b.read_time, b.writes, b.write_time, + b.writebacks, + b.writeback_time, b.extends, b.extend_time, b.op_bytes, diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c index caad642ec9..4c3540d6e1 100644 --- a/src/backend/postmaster/bgwriter.c +++ b/src/backend/postmaster/bgwriter.c @@ -129,7 +129,7 @@ BackgroundWriterMain(void) ALLOCSET_DEFAULT_SIZES); MemoryContextSwitchTo(bgwriter_context); - WritebackContextInit(&wb_context, &bgwriter_flush_after); + WritebackContextInit(&wb_context, IOCONTEXT_NORMAL, &bgwriter_flush_after); /* * If an exception is encountered, processing resumes here. @@ -185,7 +185,7 @@ BackgroundWriterMain(void) MemoryContextResetAndDeleteChildren(bgwriter_context); /* re-initialize to avoid repeated errors causing problems */ - WritebackContextInit(&wb_context, &bgwriter_flush_after); + WritebackContextInit(&wb_context, IOCONTEXT_NORMAL, &bgwriter_flush_after); /* Now we can allow interrupts again */ RESUME_INTERRUPTS(); diff --git a/src/backend/storage/buffer/buf_init.c b/src/backend/storage/buffer/buf_init.c index 0057443f0c..1d80532f3b 100644 --- a/src/backend/storage/buffer/buf_init.c +++ b/src/backend/storage/buffer/buf_init.c @@ -146,7 +146,7 @@ InitBufferPool(void) StrategyInitialize(!foundDescs); /* Initialize per-backend file flush context */ - WritebackContextInit(&BackendWritebackContext, + WritebackContextInit(&BackendWritebackContext, IOCONTEXT_NORMAL, &backend_flush_after); } diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c index 1fa689052e..188e135feb 100644 --- a/src/backend/storage/buffer/bufmgr.c +++ b/src/backend/storage/buffer/bufmgr.c @@ -1685,6 +1685,7 @@ again: FlushBuffer(buf_hdr, NULL, IOOBJECT_RELATION, io_context); LWLockRelease(content_lock); + BackendWritebackContext.io_context = io_context; ScheduleBufferTagForWriteback(&BackendWritebackContext, &buf_hdr->tag); } @@ -2555,7 +2556,7 @@ BufferSync(int flags) if (num_to_scan == 0) return; /* nothing to do */ - WritebackContextInit(&wb_context, &checkpoint_flush_after); + WritebackContextInit(&wb_context, IOCONTEXT_NORMAL, &checkpoint_flush_after); TRACE_POSTGRESQL_BUFFER_SYNC_START(NBuffers, num_to_scan); @@ -5433,10 +5434,11 @@ ts_ckpt_progress_comparator(Datum a, Datum b, void *arg) * writeback control will be performed. */ void -WritebackContextInit(WritebackContext *context, int *max_pending) +WritebackContextInit(WritebackContext *context, IOContext io_context, int *max_pending) { Assert(*max_pending <= WRITEBACK_MAX_PENDING_FLUSHES); + context->io_context = io_context; context->max_pending = max_pending; context->nr_pending = 0; } @@ -5491,6 +5493,7 @@ ScheduleBufferTagForWriteback(WritebackContext *context, BufferTag *tag) void IssuePendingWritebacks(WritebackContext *context) { + instr_time io_start; int i; if (context->nr_pending == 0) @@ -5502,6 +5505,8 @@ IssuePendingWritebacks(WritebackContext *context) */ sort_pending_writebacks(context->pending_writebacks, context->nr_pending); + io_start = pgstat_prepare_io_time(); + /* * Coalesce neighbouring writes, but nothing else. For that we iterate * through the, now sorted, array of pending flushes, and look forward to @@ -5555,6 +5560,9 @@ IssuePendingWritebacks(WritebackContext *context) smgrwriteback(reln, BufTagGetForkNum(&tag), tag.blockNum, nblocks); } + pgstat_count_io_op_time(IOOBJECT_RELATION, context->io_context, IOOP_WRITEBACK, + io_start, context->nr_pending); + context->nr_pending = 0; } diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c index 0d57b6a7c0..70da0a2de1 100644 --- a/src/backend/utils/adt/pgstatfuncs.c +++ b/src/backend/utils/adt/pgstatfuncs.c @@ -1268,6 +1268,8 @@ typedef enum io_stat_col IO_COL_READ_TIME, IO_COL_WRITES, IO_COL_WRITE_TIME, + IO_COL_WRITEBACKS, + IO_COL_WRITEBACK_TIME, IO_COL_EXTENDS, IO_COL_EXTEND_TIME, IO_COL_CONVERSION, @@ -1303,6 +1305,8 @@ pgstat_get_io_op_index(IOOp io_op) return IO_COL_REUSES; case IOOP_WRITE: return IO_COL_WRITES; + case IOOP_WRITEBACK: + return IO_COL_WRITEBACKS; } elog(ERROR, "unrecognized IOOp value: %d", io_op); @@ -1322,6 +1326,7 @@ pgstat_get_io_time_index(IOOp io_op) { case IOOP_READ: case IOOP_WRITE: + case IOOP_WRITEBACK: case IOOP_EXTEND: case IOOP_FSYNC: return pgstat_get_io_op_index(io_op) + 1; diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index b2bc81b15f..e766b9b600 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -5760,9 +5760,9 @@ proname => 'pg_stat_get_io', provolatile => 'v', prorows => '30', proretset => 't', proparallel => 'r', prorettype => 'record', proargtypes => '', - proallargtypes => '{text,text,text,int8,float8,int8,float8,int8,float8,int8,int8,int8,int8,int8,float8,timestamptz}', - proargmodes => '{o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', - proargnames => '{backend_type,object,context,reads,read_time,writes,write_time,extends,extend_time,op_bytes,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}', + proallargtypes => '{text,text,text,int8,float8,int8,float8,int8,float8,int8,float8,int8,int8,int8,int8,int8,float8,timestamptz}', + proargmodes => '{o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}', + proargnames => '{backend_type,object,context,reads,read_time,writes,write_time,writebacks,writeback_time,extends,extend_time,op_bytes,hits,evictions,reuses,fsyncs,fsync_time,stats_reset}', prosrc => 'pg_stat_get_io' }, { oid => '1136', descr => 'statistics: information about WAL activity', diff --git a/src/include/pgstat.h b/src/include/pgstat.h index fff4ad5b6d..57a2c0866a 100644 --- a/src/include/pgstat.h +++ b/src/include/pgstat.h @@ -300,9 +300,10 @@ typedef enum IOOp IOOP_READ, IOOP_REUSE, IOOP_WRITE, + IOOP_WRITEBACK, } IOOp; -#define IOOP_NUM_TYPES (IOOP_WRITE + 1) +#define IOOP_NUM_TYPES (IOOP_WRITEBACK + 1) typedef struct PgStat_BktypeIO { diff --git a/src/include/storage/buf_internals.h b/src/include/storage/buf_internals.h index 136cf8fbaf..331ca26ce3 100644 --- a/src/include/storage/buf_internals.h +++ b/src/include/storage/buf_internals.h @@ -295,6 +295,8 @@ typedef struct PendingWriteback /* struct forward declared in bufmgr.h */ typedef struct WritebackContext { + IOContext io_context; + /* pointer to the max number of writeback requests to coalesce */ int *max_pending; @@ -387,7 +389,7 @@ extern PGDLLIMPORT CkptSortItem *CkptBufferIds; * Internal buffer management routines */ /* bufmgr.c */ -extern void WritebackContextInit(WritebackContext *context, int *max_pending); +extern void WritebackContextInit(WritebackContext *context, IOContext io_context, int *max_pending); extern void IssuePendingWritebacks(WritebackContext *context); extern void ScheduleBufferTagForWriteback(WritebackContext *context, BufferTag *tag); diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 69957687fe..0bd6db2bf8 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1887,6 +1887,8 @@ pg_stat_io| SELECT backend_type, read_time, writes, write_time, + writebacks, + writeback_time, extends, extend_time, op_bytes, @@ -1896,7 +1898,7 @@ pg_stat_io| SELECT backend_type, fsyncs, fsync_time, stats_reset - FROM pg_stat_get_io() b(backend_type, object, context, reads, read_time, writes, write_time, extends, extend_time, op_bytes, hits, evictions, reuses, fsyncs, fsync_time, stats_reset); + FROM pg_stat_get_io() b(backend_type, object, context, reads, read_time, writes, write_time, writebacks, writeback_time, extends, extend_time, op_bytes, hits, evictions, reuses, fsyncs, fsync_time, stats_reset); pg_stat_progress_analyze| SELECT s.pid, s.datid, d.datname, -- 2.37.2