diff options
Diffstat (limited to 'src/backend/postmaster/autovacuum.c')
| -rw-r--r-- | src/backend/postmaster/autovacuum.c | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c index 72a5c4a..356678b 100644 --- a/src/backend/postmaster/autovacuum.c +++ b/src/backend/postmaster/autovacuum.c @@ -76,6 +76,7 @@ #include "catalog/dependency.h" #include "catalog/namespace.h" #include "catalog/pg_database.h" +#include "catalog/pg_namespace.h" #include "commands/dbcommands.h" #include "commands/vacuum.h" #include "lib/ilist.h" @@ -2272,6 +2273,24 @@ do_autovacuum(void) continue; } + /* + * Try to lock the temp namespace, too. Even though we have lock on + * the table itself, there's a risk of deadlock against an incoming + * backend trying to clean out the temp namespace, in case this table + * has dependencies (such as sequences) that the backend's + * performDeletion call might visit in a different order. If we can + * get AccessShareLock on the namespace, that's sufficient to ensure + * we're not running concurrently with RemoveTempRelations. If we + * can't, back off and let RemoveTempRelations do its thing. + */ + if (!ConditionalLockDatabaseObject(NamespaceRelationId, + classForm->relnamespace, 0, + AccessShareLock)) + { + UnlockRelationOid(relid, AccessExclusiveLock); + continue; + } + /* OK, let's delete it */ ereport(LOG, (errmsg("autovacuum: dropping orphan temp table \"%s.%s.%s\"", @@ -2289,7 +2308,7 @@ do_autovacuum(void) /* * To commit the deletion, end current transaction and start a new - * one. Note this also releases the lock we took. + * one. Note this also releases the locks we took. */ CommitTransactionCommand(); StartTransactionCommand(); |