We should also apply the attached patch, which corrects a minor issue
with the conditions for flagging transactions that could potentially
make a snapshot unsafe.
There's a small window wherein a transaction is committed but not yet
on the finished list, and we shouldn't flag it as a potential conflict
if so. We can also skip adding a doomed transaction to the list of
possible conflicts because we know it won't commit.
This is not really a related issue, but Kevin and I found it while
looking into this issue, and it was included in the patch we sent out.
Dan
--
Dan R. K. Ports MIT CSAIL http://drkp.net/
*** a/src/backend/storage/lmgr/predicate.c
--- b/src/backend/storage/lmgr/predicate.c
***************
*** 1669,1676 **** RegisterSerializableTransactionInt(Snapshot snapshot)
othersxact != NULL;
othersxact = NextPredXact(othersxact))
{
! if (!SxactIsOnFinishedList(othersxact) &&
! !SxactIsReadOnly(othersxact))
{
SetPossibleUnsafeConflict(sxact, othersxact);
}
--- 1676,1684 ----
othersxact != NULL;
othersxact = NextPredXact(othersxact))
{
! if (!SxactIsCommitted(othersxact)
! && !SxactIsDoomed(othersxact)
! && !SxactIsReadOnly(othersxact))
{
SetPossibleUnsafeConflict(sxact, othersxact);
}
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