Implement rate-limiting logic on how often backends will attempt to send
messages to the stats collector. This avoids the problem that enabling stats_row_level for autovacuum has a significant overhead for short read-only transactions, as noted by Arjen van der Meijden. We can avoid an extra gettimeofday call by piggybacking on the one done for WAL-logging xact commit or abort (although that doesn't help read-only transactions, since they don't WAL-log anything). In my proposal for this, I noted that we could change the WAL log entries for commit/abort to record full TimestampTz precision, instead of only time_t as at present. That's not done in this patch, but will be committed separately.
This commit is contained in:
Tom Lane
parent
57b82bf324
commit
957d08c81f
|
|
@ -10,7 +10,7 @@
|
|||
*
|
||||
*
|
||||
* IDENTIFICATION
|
||||
* $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.240 2007/04/26 23:24:44 tgl Exp $
|
||||
* $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.241 2007/04/30 03:23:48 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
|
|
@ -160,11 +160,13 @@ static CommandId currentCommandId;
|
|||
/*
|
||||
* xactStartTimestamp is the value of transaction_timestamp().
|
||||
* stmtStartTimestamp is the value of statement_timestamp().
|
||||
* xactStopTimestamp is the time at which we log a commit or abort WAL record.
|
||||
* These do not change as we enter and exit subtransactions, so we don't
|
||||
* keep them inside the TransactionState stack.
|
||||
*/
|
||||
static TimestampTz xactStartTimestamp;
|
||||
static TimestampTz stmtStartTimestamp;
|
||||
static TimestampTz xactStopTimestamp;
|
||||
|
||||
/*
|
||||
* GID to be used for preparing the current transaction. This is also
|
||||
|
|
@ -435,6 +437,20 @@ GetCurrentStatementStartTimestamp(void)
|
|||
return stmtStartTimestamp;
|
||||
}
|
||||
|
||||
/*
|
||||
* GetCurrentTransactionStopTimestamp
|
||||
*
|
||||
* We return current time if the transaction stop time hasn't been set
|
||||
* (which can happen if we decide we don't need to log an XLOG record).
|
||||
*/
|
||||
TimestampTz
|
||||
GetCurrentTransactionStopTimestamp(void)
|
||||
{
|
||||
if (xactStopTimestamp != 0)
|
||||
return xactStopTimestamp;
|
||||
return GetCurrentTimestamp();
|
||||
}
|
||||
|
||||
/*
|
||||
* SetCurrentStatementStartTimestamp
|
||||
*/
|
||||
|
|
@ -444,6 +460,15 @@ SetCurrentStatementStartTimestamp(void)
|
|||
stmtStartTimestamp = GetCurrentTimestamp();
|
||||
}
|
||||
|
||||
/*
|
||||
* SetCurrentTransactionStopTimestamp
|
||||
*/
|
||||
static inline void
|
||||
SetCurrentTransactionStopTimestamp(void)
|
||||
{
|
||||
xactStopTimestamp = GetCurrentTimestamp();
|
||||
}
|
||||
|
||||
/*
|
||||
* GetCurrentTransactionNestLevel
|
||||
*
|
||||
|
|
@ -747,7 +772,8 @@ RecordTransactionCommit(void)
|
|||
*/
|
||||
MyProc->inCommit = true;
|
||||
|
||||
xlrec.xtime = time(NULL);
|
||||
SetCurrentTransactionStopTimestamp();
|
||||
xlrec.xtime = timestamptz_to_time_t(xactStopTimestamp);
|
||||
xlrec.nrels = nrels;
|
||||
xlrec.nsubxacts = nchildren;
|
||||
rdata[0].data = (char *) (&xlrec);
|
||||
|
|
@ -1042,7 +1068,8 @@ RecordTransactionAbort(void)
|
|||
xl_xact_abort xlrec;
|
||||
XLogRecPtr recptr;
|
||||
|
||||
xlrec.xtime = time(NULL);
|
||||
SetCurrentTransactionStopTimestamp();
|
||||
xlrec.xtime = timestamptz_to_time_t(xactStopTimestamp);
|
||||
xlrec.nrels = nrels;
|
||||
xlrec.nsubxacts = nchildren;
|
||||
rdata[0].data = (char *) (&xlrec);
|
||||
|
|
@ -1415,9 +1442,11 @@ StartTransaction(void)
|
|||
/*
|
||||
* set transaction_timestamp() (a/k/a now()). We want this to be the same
|
||||
* as the first command's statement_timestamp(), so don't do a fresh
|
||||
* GetCurrentTimestamp() call (which'd be expensive anyway).
|
||||
* GetCurrentTimestamp() call (which'd be expensive anyway). Also,
|
||||
* mark xactStopTimestamp as unset.
|
||||
*/
|
||||
xactStartTimestamp = stmtStartTimestamp;
|
||||
xactStopTimestamp = 0;
|
||||
pgstat_report_txn_timestamp(xactStartTimestamp);
|
||||
|
||||
/*
|
||||
|
|
|
|||
|
|
@ -8,7 +8,7 @@
|
|||
*
|
||||
*
|
||||
* IDENTIFICATION
|
||||
* $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.106 2007/04/19 16:26:44 alvherre Exp $
|
||||
* $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.107 2007/04/30 03:23:48 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
|
|
@ -468,29 +468,15 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt)
|
|||
/* Log the action if appropriate */
|
||||
if (IsAutoVacuumWorkerProcess() && Log_autovacuum >= 0)
|
||||
{
|
||||
long diff = 0L;
|
||||
|
||||
if (Log_autovacuum > 0)
|
||||
{
|
||||
TimestampTz endtime;
|
||||
int usecs;
|
||||
long secs;
|
||||
|
||||
endtime = GetCurrentTimestamp();
|
||||
TimestampDifference(starttime, endtime, &secs, &usecs);
|
||||
|
||||
diff = secs * 1000 + usecs / 1000;
|
||||
}
|
||||
|
||||
if (Log_autovacuum == 0 || diff >= Log_autovacuum)
|
||||
{
|
||||
if (Log_autovacuum == 0 ||
|
||||
TimestampDifferenceExceeds(starttime, GetCurrentTimestamp(),
|
||||
Log_autovacuum))
|
||||
ereport(LOG,
|
||||
(errmsg("automatic analyze of table \"%s.%s.%s\" system usage: %s",
|
||||
get_database_name(MyDatabaseId),
|
||||
get_namespace_name(RelationGetNamespace(onerel)),
|
||||
RelationGetRelationName(onerel),
|
||||
pg_rusage_show(&ru0))));
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
|
|
|
|||
|
|
@ -36,7 +36,7 @@
|
|||
*
|
||||
*
|
||||
* IDENTIFICATION
|
||||
* $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.87 2007/04/19 16:26:44 alvherre Exp $
|
||||
* $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.88 2007/04/30 03:23:48 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
|
|
@ -217,22 +217,9 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt)
|
|||
/* and log the action if appropriate */
|
||||
if (IsAutoVacuumWorkerProcess() && Log_autovacuum >= 0)
|
||||
{
|
||||
long diff = 0L;
|
||||
|
||||
if (Log_autovacuum > 0)
|
||||
{
|
||||
TimestampTz endtime;
|
||||
int usecs;
|
||||
long secs;
|
||||
|
||||
endtime = GetCurrentTimestamp();
|
||||
TimestampDifference(starttime, endtime, &secs, &usecs);
|
||||
|
||||
diff = secs * 1000 + usecs / 1000;
|
||||
}
|
||||
|
||||
if (Log_autovacuum == 0 || diff >= Log_autovacuum)
|
||||
{
|
||||
if (Log_autovacuum == 0 ||
|
||||
TimestampDifferenceExceeds(starttime, GetCurrentTimestamp(),
|
||||
Log_autovacuum))
|
||||
ereport(LOG,
|
||||
(errmsg("automatic vacuum of table \"%s.%s.%s\": index scans: %d\n"
|
||||
"pages: %d removed, %d remain\n"
|
||||
|
|
@ -245,7 +232,6 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt)
|
|||
vacrelstats->pages_removed, vacrelstats->rel_pages,
|
||||
vacrelstats->tuples_deleted, vacrelstats->rel_tuples,
|
||||
pg_rusage_show(&ru0))));
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
|
|
|
|||
|
|
@ -13,7 +13,7 @@
|
|||
*
|
||||
* Copyright (c) 2001-2007, PostgreSQL Global Development Group
|
||||
*
|
||||
* $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.153 2007/04/21 04:10:53 tgl Exp $
|
||||
* $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.154 2007/04/30 03:23:49 tgl Exp $
|
||||
* ----------
|
||||
*/
|
||||
#include "postgres.h"
|
||||
|
|
@ -608,15 +608,34 @@ void allow_immediate_pgstat_restart(void)
|
|||
/* ----------
|
||||
* pgstat_report_tabstat() -
|
||||
*
|
||||
* Called from tcop/postgres.c to send the so far collected
|
||||
* per table access statistics to the collector.
|
||||
* Called from tcop/postgres.c to send the so far collected per-table
|
||||
* access statistics to the collector. Note that this is called only
|
||||
* when not within a transaction, so it is fair to use transaction stop
|
||||
* time as an approximation of current time.
|
||||
* ----------
|
||||
*/
|
||||
void
|
||||
pgstat_report_tabstat(void)
|
||||
{
|
||||
static TimestampTz last_report = 0;
|
||||
TimestampTz now;
|
||||
|
||||
/* Don't expend a clock check if nothing to do */
|
||||
if (RegularTabStat.tsa_used == 0 &&
|
||||
SharedTabStat.tsa_used == 0)
|
||||
return;
|
||||
|
||||
/*
|
||||
* For each message buffer used during the last query set the header
|
||||
* Don't send a message unless it's been at least PGSTAT_STAT_INTERVAL
|
||||
* msec since we last sent one.
|
||||
*/
|
||||
now = GetCurrentTransactionStopTimestamp();
|
||||
if (!TimestampDifferenceExceeds(last_report, now, PGSTAT_STAT_INTERVAL))
|
||||
return;
|
||||
last_report = now;
|
||||
|
||||
/*
|
||||
* For each message buffer used during the last queries, set the header
|
||||
* fields and send it out; then mark the entries unused.
|
||||
*/
|
||||
pgstat_report_one_tabstat(&RegularTabStat, MyDatabaseId);
|
||||
|
|
|
|||
|
|
@ -8,7 +8,7 @@
|
|||
*
|
||||
*
|
||||
* IDENTIFICATION
|
||||
* $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.174 2007/02/27 23:48:09 tgl Exp $
|
||||
* $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.175 2007/04/30 03:23:49 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
|
|
@ -1238,6 +1238,27 @@ TimestampDifference(TimestampTz start_time, TimestampTz stop_time,
|
|||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* TimestampDifferenceExceeds -- report whether the difference between two
|
||||
* timestamps is >= a threshold (expressed in milliseconds)
|
||||
*
|
||||
* Both inputs must be ordinary finite timestamps (in current usage,
|
||||
* they'll be results from GetCurrentTimestamp()).
|
||||
*/
|
||||
bool
|
||||
TimestampDifferenceExceeds(TimestampTz start_time,
|
||||
TimestampTz stop_time,
|
||||
int msec)
|
||||
{
|
||||
TimestampTz diff = stop_time - start_time;
|
||||
|
||||
#ifdef HAVE_INT64_TIMESTAMP
|
||||
return (diff >= msec * INT64CONST(1000));
|
||||
#else
|
||||
return (diff * 1000.0 >= msec);
|
||||
#endif
|
||||
}
|
||||
|
||||
/*
|
||||
* Convert a time_t to TimestampTz.
|
||||
*
|
||||
|
|
|
|||
|
|
@ -7,7 +7,7 @@
|
|||
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
|
||||
* Portions Copyright (c) 1994, Regents of the University of California
|
||||
*
|
||||
* $PostgreSQL: pgsql/src/include/access/xact.h,v 1.85 2007/03/13 00:33:42 tgl Exp $
|
||||
* $PostgreSQL: pgsql/src/include/access/xact.h,v 1.86 2007/04/30 03:23:49 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
|
|
@ -142,6 +142,7 @@ extern SubTransactionId GetCurrentSubTransactionId(void);
|
|||
extern CommandId GetCurrentCommandId(void);
|
||||
extern TimestampTz GetCurrentTransactionStartTimestamp(void);
|
||||
extern TimestampTz GetCurrentStatementStartTimestamp(void);
|
||||
extern TimestampTz GetCurrentTransactionStopTimestamp(void);
|
||||
extern void SetCurrentStatementStartTimestamp(void);
|
||||
extern int GetCurrentTransactionNestLevel(void);
|
||||
extern bool TransactionIdIsCurrentTransactionId(TransactionId xid);
|
||||
|
|
|
|||
|
|
@ -6,7 +6,7 @@
|
|||
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
|
||||
* Portions Copyright (c) 1994, Regents of the University of California
|
||||
*
|
||||
* $PostgreSQL: pgsql/src/include/utils/timestamp.h,v 1.67 2007/02/16 03:39:45 momjian Exp $
|
||||
* $PostgreSQL: pgsql/src/include/utils/timestamp.h,v 1.68 2007/04/30 03:23:49 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
|
|
@ -311,6 +311,9 @@ extern TimestampTz GetCurrentTimestamp(void);
|
|||
|
||||
extern void TimestampDifference(TimestampTz start_time, TimestampTz stop_time,
|
||||
long *secs, int *microsecs);
|
||||
extern bool TimestampDifferenceExceeds(TimestampTz start_time,
|
||||
TimestampTz stop_time,
|
||||
int msec);
|
||||
|
||||
extern TimestampTz time_t_to_timestamptz(time_t tm);
|
||||
extern time_t timestamptz_to_time_t(TimestampTz t);
|
||||
|
|
|
|||
|
|
@ -73,6 +73,14 @@ SELECT count(*) FROM tenk2 WHERE unique1 = 1;
|
|||
1
|
||||
(1 row)
|
||||
|
||||
-- force the rate-limiting logic in pgstat_report_tabstat() to time out
|
||||
-- and send a message
|
||||
SELECT pg_sleep(1.0);
|
||||
pg_sleep
|
||||
----------
|
||||
|
||||
(1 row)
|
||||
|
||||
-- wait for stats collector to update
|
||||
SELECT wait_for_stats();
|
||||
wait_for_stats
|
||||
|
|
|
|||
|
|
@ -60,6 +60,10 @@ SELECT count(*) FROM tenk2;
|
|||
-- do an indexscan
|
||||
SELECT count(*) FROM tenk2 WHERE unique1 = 1;
|
||||
|
||||
-- force the rate-limiting logic in pgstat_report_tabstat() to time out
|
||||
-- and send a message
|
||||
SELECT pg_sleep(1.0);
|
||||
|
||||
-- wait for stats collector to update
|
||||
SELECT wait_for_stats();
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue