Clear I/O timing counters after sending them to the stats collector.

tglsfdc · tglsfdc · commit cdbad241f413 · 2012-04-28T15:11:13.000-04:00
This oversight caused the reported times to accumulate in an O(N^2)
fashion the longer a backend runs.
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
@@ -784,8 +784,8 @@ pgstat_send_tabstat(PgStat_MsgTabstat *tsmsg)
 		return;
 
 	/*
-	 * Report accumulated xact commit/rollback and I/O timings whenever we send
-	 * a normal tabstat message
+	 * Report and reset accumulated xact commit/rollback and I/O timings
+	 * whenever we send a normal tabstat message
 	 */
 	if (OidIsValid(tsmsg->m_databaseid))
 	{
@@ -795,6 +795,8 @@ pgstat_send_tabstat(PgStat_MsgTabstat *tsmsg)
 		tsmsg->m_block_time_write = pgStatBlockTimeWrite;
 		pgStatXactCommit = 0;
 		pgStatXactRollback = 0;
+		pgStatBlockTimeRead = 0;
+		pgStatBlockTimeWrite = 0;
 	}
 	else
 	{

Original file line number	Diff line number	Diff line change
`@@ -784,8 +784,8 @@ pgstat_send_tabstat(PgStat_MsgTabstat *tsmsg)`
`784`	`784`	`return;`
`785`	`785`
`786`	`786`	`/*`
`787`		`- * Report accumulated xact commit/rollback and I/O timings whenever we send`
`788`		`- * a normal tabstat message`
	`787`	`+ * Report and reset accumulated xact commit/rollback and I/O timings`
	`788`	`+ * whenever we send a normal tabstat message`
`789`	`789`	`*/`
`790`	`790`	`if (OidIsValid(tsmsg->m_databaseid))`
`791`	`791`	`{`
`@@ -795,6 +795,8 @@ pgstat_send_tabstat(PgStat_MsgTabstat *tsmsg)`
`795`	`795`	`tsmsg->m_block_time_write = pgStatBlockTimeWrite;`
`796`	`796`	`pgStatXactCommit = 0;`
`797`	`797`	`pgStatXactRollback = 0;`
	`798`	`+ pgStatBlockTimeRead = 0;`
	`799`	`+ pgStatBlockTimeWrite = 0;`
`798`	`800`	`}`
`799`	`801`	`else`
`800`	`802`	`{`