diff options
Diffstat (limited to 'src/backend/postmaster/autovacuum.c')
| -rw-r--r-- | src/backend/postmaster/autovacuum.c | 112 |
1 files changed, 72 insertions, 40 deletions
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c index 6f9bfe2e9af..d9d691479d9 100644 --- a/src/backend/postmaster/autovacuum.c +++ b/src/backend/postmaster/autovacuum.c @@ -10,7 +10,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.21 2006/06/27 22:16:43 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.22 2006/07/10 16:20:50 alvherre Exp $ * *------------------------------------------------------------------------- */ @@ -79,7 +79,7 @@ typedef struct autovac_dbase { Oid oid; char *name; - TransactionId frozenxid; + TransactionId minxid; TransactionId vacuumxid; PgStat_StatDBEntry *entry; int32 age; @@ -126,10 +126,6 @@ autovac_start(void) time_t curtime; pid_t AutoVacPID; - /* Do nothing if no autovacuum process needed */ - if (!AutoVacuumingActive()) - return 0; - /* * Do nothing if too soon since last autovacuum exit. This limits how * often the daemon runs. Since the time per iteration can be quite @@ -144,6 +140,7 @@ autovac_start(void) * * XXX todo: implement sleep scale factor that existed in contrib code. */ + curtime = time(NULL); if ((unsigned int) (curtime - last_autovac_stop_time) < (unsigned int) autovacuum_naptime) @@ -334,6 +331,14 @@ AutoVacMain(int argc, char *argv[]) * connected to it since the stats were last initialized, it doesn't need * vacuuming. * + * Note that if we are called when autovacuum is nominally disabled in + * postgresql.conf, we assume the postmaster has invoked us because a + * database is in danger of Xid wraparound. In that case, we only + * consider vacuuming whole databases, not individual tables; and we pick + * the oldest one, regardless of it's true age. So the criteria for + * deciding that a database needs a database-wide vacuum is elsewhere + * (currently in vac_truncate_clog). + * * XXX This could be improved if we had more info about whether it needs * vacuuming before connecting to it. Perhaps look through the pgstats * data for the database's tables? One idea is to keep track of the @@ -344,13 +349,8 @@ AutoVacMain(int argc, char *argv[]) db = NULL; whole_db = false; - foreach(cell, dblist) + if (AutoVacuumingActive()) { - autovac_dbase *tmp = lfirst(cell); - bool this_whole_db; - int32 freeze_age, - vacuum_age; - /* * We look for the database that most urgently needs a database-wide * vacuum. We decide that a database-wide vacuum is needed 100000 @@ -361,38 +361,70 @@ AutoVacMain(int argc, char *argv[]) * Unlike vacuum.c, we also look at vacuumxid. This is so that * pg_clog can be kept trimmed to a reasonable size. */ - freeze_age = (int32) (nextXid - tmp->frozenxid); - vacuum_age = (int32) (nextXid - tmp->vacuumxid); - tmp->age = Max(freeze_age, vacuum_age); - - this_whole_db = (tmp->age > - (int32) ((MaxTransactionId >> 3) * 3 - 100000)); - if (whole_db || this_whole_db) + foreach(cell, dblist) { - if (!this_whole_db) - continue; - if (db == NULL || tmp->age > db->age) + autovac_dbase *tmp = lfirst(cell); + bool this_whole_db; + int32 true_age, + vacuum_age; + + true_age = (int32) (nextXid - tmp->minxid); + vacuum_age = (int32) (nextXid - tmp->vacuumxid); + tmp->age = Max(true_age, vacuum_age); + + this_whole_db = (tmp->age > + (int32) ((MaxTransactionId >> 3) * 3 - 100000)); + + if (whole_db || this_whole_db) { - db = tmp; - whole_db = true; + if (!this_whole_db) + continue; + if (db == NULL || tmp->age > db->age) + { + db = tmp; + whole_db = true; + } + continue; } - continue; - } - /* - * Otherwise, skip a database with no pgstat entry; it means it hasn't - * seen any activity. - */ - tmp->entry = pgstat_fetch_stat_dbentry(tmp->oid); - if (!tmp->entry) - continue; + /* + * Otherwise, skip a database with no pgstat entry; it means it hasn't + * seen any activity. + */ + tmp->entry = pgstat_fetch_stat_dbentry(tmp->oid); + if (!tmp->entry) + continue; + /* + * Remember the db with oldest autovac time. + */ + if (db == NULL || + tmp->entry->last_autovac_time < db->entry->last_autovac_time) + db = tmp; + } + } + else + { /* - * Remember the db with oldest autovac time. + * If autovacuuming is not active, we must have gotten here because a + * backend signalled the postmaster. Pick up the database with the + * greatest age, and apply a database-wide vacuum on it. */ - if (db == NULL || - tmp->entry->last_autovac_time < db->entry->last_autovac_time) - db = tmp; + int32 oldest = 0; + + whole_db = true; + foreach(cell, dblist) + { + autovac_dbase *tmp = lfirst(cell); + int32 age = (int32) (nextXid - tmp->minxid); + + if (age > oldest) + { + oldest = age; + db = tmp; + } + } + Assert(db); } if (db) @@ -454,7 +486,7 @@ autovac_get_database_list(void) FILE *db_file; Oid db_id; Oid db_tablespace; - TransactionId db_frozenxid; + TransactionId db_minxid; TransactionId db_vacuumxid; filename = database_getflatfilename(); @@ -465,7 +497,7 @@ autovac_get_database_list(void) errmsg("could not open file \"%s\": %m", filename))); while (read_pg_database_line(db_file, thisname, &db_id, - &db_tablespace, &db_frozenxid, + &db_tablespace, &db_minxid, &db_vacuumxid)) { autovac_dbase *db; @@ -474,7 +506,7 @@ autovac_get_database_list(void) db->oid = db_id; db->name = pstrdup(thisname); - db->frozenxid = db_frozenxid; + db->minxid = db_minxid; db->vacuumxid = db_vacuumxid; /* these get set later: */ db->entry = NULL; |