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Commita0abe87

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committed
Separate the code to start a new worker into its own function. The code is
exactly the same, modulo whitespace.
1 parent6287eb7 commita0abe87

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1 file changed

+100
-85
lines changed

1 file changed

+100
-85
lines changed

‎src/backend/postmaster/autovacuum.c

Lines changed: 100 additions & 85 deletions
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@
1010
*
1111
*
1212
* IDENTIFICATION
13-
* $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.36 2007/03/23 21:23:13 alvherre Exp $
13+
* $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.37 2007/03/23 21:45:17 alvherre Exp $
1414
*
1515
*-------------------------------------------------------------------------
1616
*/
@@ -118,6 +118,7 @@ static pid_t avworker_forkexec(void);
118118
NON_EXEC_STATICvoidAutoVacWorkerMain(intargc,char*argv[]);
119119
NON_EXEC_STATICvoidAutoVacLauncherMain(intargc,char*argv[]);
120120

121+
staticvoiddo_start_worker(void);
121122
staticvoiddo_autovacuum(PgStat_StatDBEntry*dbentry);
122123
staticList*autovac_get_database_list(void);
123124
staticvoidtest_rel_for_autovac(Oidrelid,PgStat_StatTabEntry*tabentry,
@@ -218,9 +219,6 @@ NON_EXEC_STATIC void
218219
AutoVacLauncherMain(intargc,char*argv[])
219220
{
220221
sigjmp_buflocal_sigjmp_buf;
221-
List*dblist;
222-
boolfor_xid_wrap;
223-
autovac_dbase*db;
224222
MemoryContextavlauncher_cxt;
225223

226224
/* we are a postmaster subprocess now */
@@ -358,8 +356,6 @@ AutoVacLauncherMain(int argc, char *argv[])
358356

359357
for (;;)
360358
{
361-
TransactionIdxidForceLimit;
362-
ListCell*cell;
363359
intworker_pid;
364360

365361
/*
@@ -407,86 +403,8 @@ AutoVacLauncherMain(int argc, char *argv[])
407403
}
408404
}
409405

410-
/* Get a list of databases */
411-
dblist=autovac_get_database_list();
406+
do_start_worker();
412407

413-
/*
414-
* Determine the oldest datfrozenxid/relfrozenxid that we will allow
415-
* to pass without forcing a vacuum. (This limit can be tightened for
416-
* particular tables, but not loosened.)
417-
*/
418-
recentXid=ReadNewTransactionId();
419-
xidForceLimit=recentXid-autovacuum_freeze_max_age;
420-
/* ensure it's a "normal" XID, else TransactionIdPrecedes misbehaves */
421-
if (xidForceLimit<FirstNormalTransactionId)
422-
xidForceLimit-=FirstNormalTransactionId;
423-
424-
/*
425-
* Choose a database to connect to. We pick the database that was least
426-
* recently auto-vacuumed, or one that needs vacuuming to prevent Xid
427-
* wraparound-related data loss. If any db at risk of wraparound is
428-
* found, we pick the one with oldest datfrozenxid, independently of
429-
* autovacuum times.
430-
*
431-
* Note that a database with no stats entry is not considered, except for
432-
* Xid wraparound purposes. The theory is that if no one has ever
433-
* connected to it since the stats were last initialized, it doesn't need
434-
* vacuuming.
435-
*
436-
* XXX This could be improved if we had more info about whether it needs
437-
* vacuuming before connecting to it. Perhaps look through the pgstats
438-
* data for the database's tables? One idea is to keep track of the
439-
* number of new and dead tuples per database in pgstats. However it
440-
* isn't clear how to construct a metric that measures that and not cause
441-
* starvation for less busy databases.
442-
*/
443-
db=NULL;
444-
for_xid_wrap= false;
445-
foreach(cell,dblist)
446-
{
447-
autovac_dbase*tmp=lfirst(cell);
448-
449-
/* Find pgstat entry if any */
450-
tmp->entry=pgstat_fetch_stat_dbentry(tmp->oid);
451-
452-
/* Check to see if this one is at risk of wraparound */
453-
if (TransactionIdPrecedes(tmp->frozenxid,xidForceLimit))
454-
{
455-
if (db==NULL||
456-
TransactionIdPrecedes(tmp->frozenxid,db->frozenxid))
457-
db=tmp;
458-
for_xid_wrap= true;
459-
continue;
460-
}
461-
elseif (for_xid_wrap)
462-
continue;/* ignore not-at-risk DBs */
463-
464-
/*
465-
* Otherwise, skip a database with no pgstat entry; it means it
466-
* hasn't seen any activity.
467-
*/
468-
if (!tmp->entry)
469-
continue;
470-
471-
/*
472-
* Remember the db with oldest autovac time. (If we are here,
473-
* both tmp->entry and db->entry must be non-null.)
474-
*/
475-
if (db==NULL||
476-
tmp->entry->last_autovac_time<db->entry->last_autovac_time)
477-
db=tmp;
478-
}
479-
480-
/* Found a database -- process it */
481-
if (db!=NULL)
482-
{
483-
LWLockAcquire(AutovacuumLock,LW_EXCLUSIVE);
484-
AutoVacuumShmem->process_db=db->oid;
485-
LWLockRelease(AutovacuumLock);
486-
487-
SendPostmasterSignal(PMSIGNAL_START_AUTOVAC_WORKER);
488-
}
489-
490408
sleep:
491409
/*
492410
* in emergency mode, exit immediately so that the postmaster can
@@ -512,6 +430,103 @@ AutoVacLauncherMain(int argc, char *argv[])
512430
proc_exit(0);/* done */
513431
}
514432

433+
/*
434+
* do_start_worker
435+
*
436+
* Bare-bones procedure for starting an autovacuum worker from the launcher.
437+
* It determines what database to work on, sets up shared memory stuff and
438+
* signals postmaster to start the worker.
439+
*/
440+
staticvoid
441+
do_start_worker(void)
442+
{
443+
List*dblist;
444+
boolfor_xid_wrap;
445+
autovac_dbase*db;
446+
ListCell*cell;
447+
TransactionIdxidForceLimit;
448+
449+
/* Get a list of databases */
450+
dblist=autovac_get_database_list();
451+
452+
/*
453+
* Determine the oldest datfrozenxid/relfrozenxid that we will allow
454+
* to pass without forcing a vacuum. (This limit can be tightened for
455+
* particular tables, but not loosened.)
456+
*/
457+
recentXid=ReadNewTransactionId();
458+
xidForceLimit=recentXid-autovacuum_freeze_max_age;
459+
/* ensure it's a "normal" XID, else TransactionIdPrecedes misbehaves */
460+
if (xidForceLimit<FirstNormalTransactionId)
461+
xidForceLimit-=FirstNormalTransactionId;
462+
463+
/*
464+
* Choose a database to connect to. We pick the database that was least
465+
* recently auto-vacuumed, or one that needs vacuuming to prevent Xid
466+
* wraparound-related data loss. If any db at risk of wraparound is
467+
* found, we pick the one with oldest datfrozenxid, independently of
468+
* autovacuum times.
469+
*
470+
* Note that a database with no stats entry is not considered, except for
471+
* Xid wraparound purposes. The theory is that if no one has ever
472+
* connected to it since the stats were last initialized, it doesn't need
473+
* vacuuming.
474+
*
475+
* XXX This could be improved if we had more info about whether it needs
476+
* vacuuming before connecting to it. Perhaps look through the pgstats
477+
* data for the database's tables? One idea is to keep track of the
478+
* number of new and dead tuples per database in pgstats. However it
479+
* isn't clear how to construct a metric that measures that and not cause
480+
* starvation for less busy databases.
481+
*/
482+
db=NULL;
483+
for_xid_wrap= false;
484+
foreach(cell,dblist)
485+
{
486+
autovac_dbase*tmp=lfirst(cell);
487+
488+
/* Find pgstat entry if any */
489+
tmp->entry=pgstat_fetch_stat_dbentry(tmp->oid);
490+
491+
/* Check to see if this one is at risk of wraparound */
492+
if (TransactionIdPrecedes(tmp->frozenxid,xidForceLimit))
493+
{
494+
if (db==NULL||
495+
TransactionIdPrecedes(tmp->frozenxid,db->frozenxid))
496+
db=tmp;
497+
for_xid_wrap= true;
498+
continue;
499+
}
500+
elseif (for_xid_wrap)
501+
continue;/* ignore not-at-risk DBs */
502+
503+
/*
504+
* Otherwise, skip a database with no pgstat entry; it means it
505+
* hasn't seen any activity.
506+
*/
507+
if (!tmp->entry)
508+
continue;
509+
510+
/*
511+
* Remember the db with oldest autovac time. (If we are here,
512+
* both tmp->entry and db->entry must be non-null.)
513+
*/
514+
if (db==NULL||
515+
tmp->entry->last_autovac_time<db->entry->last_autovac_time)
516+
db=tmp;
517+
}
518+
519+
/* Found a database -- process it */
520+
if (db!=NULL)
521+
{
522+
LWLockAcquire(AutovacuumLock,LW_EXCLUSIVE);
523+
AutoVacuumShmem->process_db=db->oid;
524+
LWLockRelease(AutovacuumLock);
525+
526+
SendPostmasterSignal(PMSIGNAL_START_AUTOVAC_WORKER);
527+
}
528+
}
529+
515530
/* SIGHUP: set flag to re-read config file at next convenient time */
516531
staticvoid
517532
avl_sighup_handler(SIGNAL_ARGS)

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