On Wed, Mar 31, 2021 at 5:47 PM vignesh C <vignes...@gmail.com> wrote: > > On Wed, Mar 31, 2021 at 2:35 PM Ajin Cherian <itsa...@gmail.com> wrote: > > > > The patch applies fine on HEAD and "make check" passes fine. No major > > comments on the patch, just a minor comment: > > > > If you could change the error from, " cannot PREPARE a transaction that has > > a lock on user catalog/system table(s)" > > to "cannot PREPARE a transaction that has an exclusive lock on user > > catalog/system table(s)" that would be a more > > accurate instruction to the user. > > > > Thanks for reviewing the patch. > Please find the updated patch which includes the fix for the same.
This similar problem exists in case of synchronous replication setup having synchronous_standby_names referring to the subscriber, when we do the steps "begin;lock pg_class; insert into test1 values(10); commit". In this case while decoding of commit, the commit will wait while trying to acquire a lock on pg_class relation, stack trace for the same is given below: #4 0x0000556936cd5d37 in ProcSleep (locallock=0x556937de8728, lockMethodTable=0x5569371c2620 <default_lockmethod>) at proc.c:1361 #5 0x0000556936cc294a in WaitOnLock (locallock=0x556937de8728, owner=0x556937e3cd90) at lock.c:1858 #6 0x0000556936cc1231 in LockAcquireExtended (locktag=0x7ffcbb23cff0, lockmode=1, sessionLock=false, dontWait=false, reportMemoryError=true, locallockp=0x7ffcbb23cfe8) at lock.c:1100 #7 0x0000556936cbdbce in LockRelationOid (relid=1259, lockmode=1) at lmgr.c:117 #8 0x00005569367afb12 in relation_open (relationId=1259, lockmode=1) at relation.c:56 #9 0x00005569368888a2 in table_open (relationId=1259, lockmode=1) at table.c:43 #10 0x0000556936e90a91 in RelidByRelfilenode (reltablespace=0, relfilenode=16385) at relfilenodemap.c:192 #11 0x0000556936c40361 in ReorderBufferProcessTXN (rb=0x556937e8e760, txn=0x556937eb8778, commit_lsn=23752880, snapshot_now=0x556937ea0a90, command_id=0, streaming=false) at reorderbuffer.c:2122 #12 0x0000556936c411b7 in ReorderBufferReplay (txn=0x556937eb8778, rb=0x556937e8e760, xid=590, commit_lsn=23752880, end_lsn=23752928, commit_time=672204445820756, origin_id=0, origin_lsn=0) at reorderbuffer.c:2589 #13 0x0000556936c41239 in ReorderBufferCommit (rb=0x556937e8e760, xid=590, commit_lsn=23752880, end_lsn=23752928, commit_time=672204445820756, origin_id=0, origin_lsn=0) at reorderbuffer.c:2613 #14 0x0000556936c2f4d9 in DecodeCommit (ctx=0x556937e8c750, buf=0x7ffcbb23d610, parsed=0x7ffcbb23d4b0, xid=590, two_phase=false) at decode.c:744 Thoughts? Regards, Vignesh
