Hi,
After a DML is perfomed, the statistics is sent to pgstat by
pgsent_report_sent().
However, the mininum time between stas file update is PGSTAT_STAT_INTERVAL, so
if
a few DMLs are performed with short interval, some statistics could not be sent
until the backend is shutdown.
This is not a problem in usual cases, but in case that a session is remained in
idle for a long time, for example when using connection pooling, statistics of
a huge change of a table is not sent for a long time, and as a result, starting
autovacuum might be delayed.
An idea to resolve this is call pgsent_report_sent() again with a delay
after the last DML to make sure to send the statistics. The attached patch
implements this.
Any comments would be appreciated.
Regards,
--
Yugo Nagata <nag...@sraoss.co.jp>
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index b8d860e..928d479 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -3012,6 +3012,12 @@ ProcessInterrupts(void)
}
+ if (PgStatReportStatTimeoutPending)
+ {
+ pgstat_report_stat(false);
+ PgStatReportStatTimeoutPending = false;
+ }
+
if (ParallelMessagePending)
HandleParallelMessages();
}
@@ -4010,6 +4016,14 @@ PostgresMain(int argc, char *argv[],
ProcessCompletedNotifies();
pgstat_report_stat(false);
+ /* Call pgstat_report_stat() after PGSTAT_REPORT_STAT_DELAY
+ * again because if DMLs are performed with interval shorter
+ * than PGSTAT_STAT_INTERVAL then some statistics could not be
+ * sent until the backend is shutdown.
+ */
+ enable_timeout_after(PGSTAT_REPORT_STAT_TIMEOUT,
+ PGSTAT_REPORT_STAT_DELAY);
+
set_ps_display("idle", false);
pgstat_report_activity(STATE_IDLE, NULL);
}
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 7c09498..8c29ebd 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -31,6 +31,7 @@ volatile bool QueryCancelPending = false;
volatile bool ProcDiePending = false;
volatile bool ClientConnectionLost = false;
volatile bool IdleInTransactionSessionTimeoutPending = false;
+volatile bool PgStatReportStatTimeoutPending = false;
volatile sig_atomic_t ConfigReloadPending = false;
volatile uint32 InterruptHoldoffCount = 0;
volatile uint32 QueryCancelHoldoffCount = 0;
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index eb6960d..1df30bc 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -71,6 +71,7 @@ static void ShutdownPostgres(int code, Datum arg);
static void StatementTimeoutHandler(void);
static void LockTimeoutHandler(void);
static void IdleInTransactionSessionTimeoutHandler(void);
+static void PgStatReportStatTimeoutHandler(void);
static bool ThereIsAtLeastOneRole(void);
static void process_startup_options(Port *port, bool am_superuser);
static void process_settings(Oid databaseid, Oid roleid);
@@ -599,6 +600,8 @@ InitPostgres(const char *in_dbname, Oid dboid, const char *username,
RegisterTimeout(LOCK_TIMEOUT, LockTimeoutHandler);
RegisterTimeout(IDLE_IN_TRANSACTION_SESSION_TIMEOUT,
IdleInTransactionSessionTimeoutHandler);
+ RegisterTimeout(PGSTAT_REPORT_STAT_TIMEOUT,
+ PgStatReportStatTimeoutHandler);
}
/*
@@ -1196,6 +1199,14 @@ IdleInTransactionSessionTimeoutHandler(void)
SetLatch(MyLatch);
}
+static void
+PgStatReportStatTimeoutHandler(void)
+{
+ PgStatReportStatTimeoutPending = true;
+ InterruptPending = true;
+ SetLatch(MyLatch);
+}
+
/*
* Returns true if at least one role is defined in this database cluster.
*/
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index dad98de..4bc6f0f 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -81,6 +81,7 @@ extern PGDLLIMPORT volatile bool InterruptPending;
extern PGDLLIMPORT volatile bool QueryCancelPending;
extern PGDLLIMPORT volatile bool ProcDiePending;
extern PGDLLIMPORT volatile bool IdleInTransactionSessionTimeoutPending;
+extern PGDLLIMPORT volatile bool PgStatReportStatTimeoutPending;
extern PGDLLIMPORT volatile sig_atomic_t ConfigReloadPending;
extern volatile bool ClientConnectionLost;
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 6bffe63..a06703f 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -33,6 +33,11 @@
/* Default directory to store temporary statistics data in */
#define PG_STAT_TMP_DIR "pg_stat_tmp"
+/* How long to wait before calling pgstat_stat_report after
+ * the last DML is performed; in milliseconds.
+ */
+#define PGSTAT_REPORT_STAT_DELAY 500
+
/* Values for track_functions GUC variable --- order is significant! */
typedef enum TrackFunctionsLevel
{
diff --git a/src/include/utils/timeout.h b/src/include/utils/timeout.h
index 5a2efc0..7eccd2d 100644
--- a/src/include/utils/timeout.h
+++ b/src/include/utils/timeout.h
@@ -31,6 +31,7 @@ typedef enum TimeoutId
STANDBY_TIMEOUT,
STANDBY_LOCK_TIMEOUT,
IDLE_IN_TRANSACTION_SESSION_TIMEOUT,
+ PGSTAT_REPORT_STAT_TIMEOUT,
/* First user-definable timeout reason */
USER_TIMEOUT,
/* Maximum number of timeout reasons */
--
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