postgrespro.git / summary / log / commit / refs

commit    bdf35744bdf70208fc4d0f4b76f7d4bce3cf326b
Author:   Amit Kapila <akapila@postgresql.org>
Date:     Wed Apr 10 02:54:15 2019 +0000

    Avoid counting transaction stats for parallel worker cooperating
    transaction.
    
    The transaction that is initiated by the parallel worker to cooperate
    with the actual transaction started by the main backend to complete the
    query execution should not be counted as a separate transaction.  The
    other internal transactions started and committed by the parallel worker
    are still counted as separate transactions as we that is what we do in
    other places like autovacuum.
    
    This will partially fix the bloat in transaction stats due to additional
    transactions performed by parallel workers.  For a complete fix, we need to
    decide how we want to show all the transactions that are started internally
    for various operations and that is a matter of separate patch.
    
    Reported-by: Haribabu Kommi
    Author: Haribabu Kommi
    Reviewed-by: Amit Kapila, Jamison Kirk and Rahila Syed
    Backpatch-through: 9.6
    Discussion: https://postgr.es/m/CAJrrPGc9=jKXuScvNyQ+VNhO0FZk7LLAShAJRyZjnedd2D61EQ@mail.gmail.com


 src/backend/access/transam/twophase.c |  2 +-
 src/backend/access/transam/xact.c     |  4 ++--
 src/backend/postmaster/pgstat.c       | 22 +++++++++++++---------
 src/include/pgstat.h                  |  2 +-
 4 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c
index ecc01f741d..f9a4960f8a 100644
--- a/src/backend/access/transam/twophase.c
+++ b/src/backend/access/transam/twophase.c
@@ -1602,7 +1602,7 @@ FinishPreparedTransaction(const char *gid, bool isCommit)
 	LWLockRelease(TwoPhaseStateLock);
 
 	/* Count the prepared xact as committed or aborted */
-	AtEOXact_PgStat(isCommit);
+	AtEOXact_PgStat(isCommit, false);
 
 	/*
 	 * And now we can clean up any files we may have left.
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index bd5024ef00..816fd626ec 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -2241,7 +2241,7 @@ CommitTransaction(void)
 	AtEOXact_Files(true);
 	AtEOXact_ComboCid();
 	AtEOXact_HashTables(true);
-	AtEOXact_PgStat(true);
+	AtEOXact_PgStat(true, is_parallel_worker);
 	AtEOXact_Snapshot(true, false);
 	AtEOXact_ApplyLauncher(true);
 	pgstat_report_xact_timestamp(0);
@@ -2734,7 +2734,7 @@ AbortTransaction(void)
 		AtEOXact_Files(false);
 		AtEOXact_ComboCid();
 		AtEOXact_HashTables(false);
-		AtEOXact_PgStat(false);
+		AtEOXact_PgStat(false, is_parallel_worker);
 		AtEOXact_ApplyLauncher(false);
 		pgstat_report_xact_timestamp(0);
 	}
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 0355fa65fb..7c0b24a16f 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -2089,18 +2089,22 @@ pgstat_update_heap_dead_tuples(Relation rel, int delta)
  * ----------
  */
 void
-AtEOXact_PgStat(bool isCommit)
+AtEOXact_PgStat(bool isCommit, bool parallel)
 {
 	PgStat_SubXactStatus *xact_state;
 
-	/*
-	 * Count transaction commit or abort.  (We use counters, not just bools,
-	 * in case the reporting message isn't sent right away.)
-	 */
-	if (isCommit)
-		pgStatXactCommit++;
-	else
-		pgStatXactRollback++;
+	/* Don't count parallel worker transaction stats */
+	if (!parallel)
+	{
+		/*
+		 * Count transaction commit or abort.  (We use counters, not just
+		 * bools, in case the reporting message isn't sent right away.)
+		 */
+		if (isCommit)
+			pgStatXactCommit++;
+		else
+			pgStatXactRollback++;
+	}
 
 	/*
 	 * Transfer transactional insert/update counts into the base tabstat
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 5888242f75..a68927b57a 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -1378,7 +1378,7 @@ extern void pgstat_init_function_usage(FunctionCallInfo fcinfo,
 extern void pgstat_end_function_usage(PgStat_FunctionCallUsage *fcu,
 						  bool finalize);
 
-extern void AtEOXact_PgStat(bool isCommit);
+extern void AtEOXact_PgStat(bool isCommit, bool parallel);
 extern void AtEOSubXact_PgStat(bool isCommit, int nestDepth);
 
 extern void AtPrepare_PgStat(void);


[parent: d614aae02e8f]