diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c index 6f056e0e16904a9a004c525960f2d32a21a92e6d..fd1489947f002cefaad73ba2ff98942d8c4d47fa 100644 --- a/src/backend/postmaster/autovacuum.c +++ b/src/backend/postmaster/autovacuum.c @@ -55,7 +55,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.85 2008/11/02 21:24:52 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/postmaster/autovacuum.c,v 1.86 2008/11/03 19:03:41 alvherre Exp $ * *------------------------------------------------------------------------- */ @@ -2149,8 +2149,10 @@ do_autovacuum(void) * It could have changed if something else processed the table while * we weren't looking. * - * FIXME we ignore the possibility that the table was finished being - * vacuumed in the last 500ms (PGSTAT_STAT_INTERVAL). This is a bug. + * Note: we have a special case in pgstat code to ensure that the stats + * we read are as up-to-date as possible, to avoid the problem that + * somebody just finished vacuuming this table. The window to the race + * condition is not closed but it is very small. */ MemoryContextSwitchTo(AutovacMemCxt); tab = table_recheck_autovac(relid, table_toast_map); diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c index d3455cee1924a133afc6caafa2e9f5ab464fe06e..8fcd5f46949a53cae4f6f43e17d7d76b8794d5f7 100644 --- a/src/backend/postmaster/pgstat.c +++ b/src/backend/postmaster/pgstat.c @@ -13,7 +13,7 @@ * * Copyright (c) 2001-2008, PostgreSQL Global Development Group * - * $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.182 2008/11/03 01:17:08 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.183 2008/11/03 19:03:41 alvherre Exp $ * ---------- */ #include "postgres.h" @@ -3381,7 +3381,10 @@ backend_read_statsfile(void) /* * We set the minimum acceptable timestamp to PGSTAT_STAT_INTERVAL msec * before now. This indirectly ensures that the collector needn't write - * the file more often than PGSTAT_STAT_INTERVAL. + * the file more often than PGSTAT_STAT_INTERVAL. In an autovacuum + * worker, however, we want a lower delay to avoid using stale data, so we + * use PGSTAT_RETRY_DELAY (since the number of worker is low, this + * shouldn't be a problem). * * Note that we don't recompute min_ts after sleeping; so we might end up * accepting a file a bit older than PGSTAT_STAT_INTERVAL. In practice @@ -3389,8 +3392,12 @@ backend_read_statsfile(void) * PGSTAT_STAT_INTERVAL; and we don't want to lie to the collector about * what our cutoff time really is. */ - min_ts = TimestampTzPlusMilliseconds(GetCurrentTimestamp(), - -PGSTAT_STAT_INTERVAL); + if (IsAutoVacuumWorkerProcess()) + min_ts = TimestampTzPlusMilliseconds(GetCurrentTimestamp(), + -PGSTAT_RETRY_DELAY); + else + min_ts = TimestampTzPlusMilliseconds(GetCurrentTimestamp(), + -PGSTAT_STAT_INTERVAL); /* * Loop until fresh enough stats file is available or we ran out of time.