On 6 July 2018 at 03:30, Thomas Munro <thomas.mu...@enterprisedb.com> wrote: > On Thu, Jul 5, 2018 at 8:27 AM, Noah Misch <n...@leadboat.com> wrote: >>> However, 49bff5300d527 also introduced a similar bug where >>> subtransaction >>> commit would fail to release an AccessExclusiveLock, leaving the lock to >>> be removed sometimes early and sometimes late. This commit fixes >>> that bug also. Backpatch to PG10 needed. >> >> Subtransaction commit is too early to release an arbitrary >> AccessExclusiveLock. The primary releases every AccessExclusiveLock at >> top-level transaction commit, top-level transaction abort, or subtransaction >> abort. CommitSubTransaction() doesn't do that; it transfers locks to the >> parent sub(xact). Standby nodes can't safely remove an arbitrary lock >> earlier >> than the primary would. > > But we don't release locks acquired by committing subxacts until the > top level xact commits. Perhaps that's what the git commit message > meant by "early", as opposed to "late" meaning when > StandbyReleaseOldLocks() next runs because an XLOG_RUNNING_XACTS > record is replayed?
Locks held by subtransactions were not released at the correct timing of top-level commit; they are now. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
