diff --git a/contrib/ltree/ltxtquery_io.c b/contrib/ltree/ltxtquery_io.c
index 56bf39d145..b576676746 100644
--- a/contrib/ltree/ltxtquery_io.c
+++ b/contrib/ltree/ltxtquery_io.c
@@ -368,7 +368,7 @@ queryin(char *buf)
 		state.str = tmp;
 	}
 
-	/* set user friendly-operand view */
+	/* set user-friendly operand view */
 	memcpy((void *) GETOPERAND(query), (void *) state.op, state.sumlen);
 	pfree(state.op);
 
diff --git a/src/backend/access/gin/ginfast.c b/src/backend/access/gin/ginfast.c
index 2b3dd1c677..439a91b3e6 100644
--- a/src/backend/access/gin/ginfast.c
+++ b/src/backend/access/gin/ginfast.c
@@ -1013,7 +1013,7 @@ ginInsertCleanup(GinState *ginstate, bool full_clean,
 
 	/*
 	 * As pending list pages can have a high churn rate, it is desirable to
-	 * recycle them immediately to the FreeSpace Map when ordinary backends
+	 * recycle them immediately to the FreeSpaceMap when ordinary backends
 	 * clean the list.
 	 */
 	if (fsm_vac && fill_fsm)
diff --git a/src/backend/access/spgist/spgscan.c b/src/backend/access/spgist/spgscan.c
index 7bc5ec09bf..557dd18d7e 100644
--- a/src/backend/access/spgist/spgscan.c
+++ b/src/backend/access/spgist/spgscan.c
@@ -146,11 +146,6 @@ resetSpGistScanOpaque(SpGistScanOpaque so)
 {
 	MemoryContext oldCtx;
 
-	/*
-	 * clear traversal context before proceeding to the next scan; this must
-	 * not happen before the freeScanStack above, else we get double-free
-	 * crashes.
-	 */
 	MemoryContextReset(so->traversalCxt);
 
 	oldCtx = MemoryContextSwitchTo(so->traversalCxt);
diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
index 6189a06853..93508c2a87 100644
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -1208,7 +1208,7 @@ replace_rte_variables_mutator(Node *node,
  * a ConvertRowtypeExpr to map back to the rowtype expected by the expression.
  * (Therefore, to_rowtype had better be a child rowtype of the rowtype of the
  * RTE we're changing references to.)  Callers that don't provide to_rowtype
- * should report an error if *found_row_type is true; we don't do that here
+ * should report an error if *found_whole_row is true; we don't do that here
  * because we don't know exactly what wording for the error message would
  * be most appropriate.  The caller will be aware of the context.
  *
diff --git a/src/backend/storage/freespace/freespace.c b/src/backend/storage/freespace/freespace.c
index c17b3f49dd..dcc59f475a 100644
--- a/src/backend/storage/freespace/freespace.c
+++ b/src/backend/storage/freespace/freespace.c
@@ -417,7 +417,7 @@ fsm_space_cat_to_avail(uint8 cat)
 
 /*
  * Which category does a page need to have, to accommodate x bytes of data?
- * While fsm_size_to_avail_cat() rounds down, this needs to round up.
+ * While fsm_space_avail_to_cat() rounds down, this needs to round up.
  */
 static uint8
 fsm_space_needed_to_cat(Size needed)
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 206576d4bd..b3115e4bea 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -282,8 +282,6 @@ static const char *const numth[] = {"st", "nd", "rd", "th", NULL};
 #define ALL_UPPER		2		/* NAME */
 #define ALL_LOWER		3		/* name */
 
-#define FULL_SIZ		0
-
 #define MAX_MONTH_LEN	9
 #define MAX_MON_LEN		3
 #define MAX_DAY_LEN		9
diff --git a/src/backend/utils/mmgr/dsa.c b/src/backend/utils/mmgr/dsa.c
index 900cd8357c..42573846d5 100644
--- a/src/backend/utils/mmgr/dsa.c
+++ b/src/backend/utils/mmgr/dsa.c
@@ -2235,7 +2235,7 @@ check_for_freed_segments(dsa_area *area)
 
 	/*
 	 * Any other process that has freed a segment has incremented
-	 * free_segment_counter while holding an LWLock, and that must precede any
+	 * freed_segment_counter while holding an LWLock, and that must precede any
 	 * backend creating a new segment in the same slot while holding an
 	 * LWLock, and that must precede the creation of any dsa_pointer pointing
 	 * into the new segment which might reach us here, and the caller must
diff --git a/src/bin/pg_upgrade/pg_upgrade.c b/src/bin/pg_upgrade/pg_upgrade.c
index ff78929707..d1975aab2b 100644
--- a/src/bin/pg_upgrade/pg_upgrade.c
+++ b/src/bin/pg_upgrade/pg_upgrade.c
@@ -264,7 +264,7 @@ prepare_new_cluster(void)
 {
 	/*
 	 * It would make more sense to freeze after loading the schema, but that
-	 * would cause us to lose the frozenids restored by the load. We use
+	 * would cause us to lose the frozenxids restored by the load. We use
 	 * --analyze so autovacuum doesn't update statistics later
 	 */
 	prep_status("Analyzing all rows in the new cluster");
diff --git a/src/include/storage/fsm_internals.h b/src/include/storage/fsm_internals.h
index 0e27db07f2..0ec5a7966f 100644
--- a/src/include/storage/fsm_internals.h
+++ b/src/include/storage/fsm_internals.h
@@ -1,6 +1,6 @@
 /*-------------------------------------------------------------------------
  *
- * fsm_internal.h
+ * fsm_internals.h
  *	  internal functions for free space map
  *
  *
diff --git a/src/test/perl/TestLib.pm b/src/test/perl/TestLib.pm
index d2a9828dc6..6195c21c59 100644
--- a/src/test/perl/TestLib.pm
+++ b/src/test/perl/TestLib.pm
@@ -430,7 +430,7 @@ sub command_exit_is
 	# header file). IPC::Run's result function always returns exit code >> 8,
 	# assuming the Unix convention, which will always return 0 on Windows as
 	# long as the process was not terminated by an exception. To work around
-	# that, use $h->full_result on Windows instead.
+	# that, use $h->full_results on Windows instead.
 	my $result =
 	    ($Config{osname} eq "MSWin32")
 	  ? ($h->full_results)[0]