diff options
| -rw-r--r-- | src/backend/catalog/aclchk.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/src/backend/catalog/aclchk.c b/src/backend/catalog/aclchk.c index 9ca8a88dc91..24948c1f05e 100644 --- a/src/backend/catalog/aclchk.c +++ b/src/backend/catalog/aclchk.c @@ -659,6 +659,20 @@ ExecGrantStmt_oids(InternalGrant *istmt) * objectNamesToOids * * Turn a list of object names of a given type into an Oid list. + * + * XXX This function intentionally takes only an AccessShareLock. In the face + * of concurrent DDL, we might easily latch onto an old version of an object, + * causing the GRANT or REVOKE statement to fail. But it does prevent the + * object from disappearing altogether. To do better, we would need to use a + * self-exclusive lock, perhaps ShareUpdateExclusiveLock, here and before + * *every* CatalogTupleUpdate() of a row that GRANT/REVOKE can affect. + * Besides that additional work, this could have operational costs. For + * example, it would make GRANT ALL TABLES IN SCHEMA terminate every + * autovacuum running in the schema and consume a shared lock table entry per + * table in the schema. The user-visible benefit of that additional work is + * just changing "ERROR: tuple concurrently updated" to blocking. That's not + * nothing, but it might not outweigh autovacuum termination and lock table + * consumption spikes. */ static List * objectNamesToOids(ObjectType objtype, List *objnames, bool is_grant) |