There's a small window wherein a transaction is committed but not yet

hlinnaka · hlinnaka · commit bdaabb9b22ca · 2011-07-08T00:36:30.000+03:00
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.

Dan Ports and Kevin Grittner.
diff --git a/src/backend/storage/lmgr/predicate.c b/src/backend/storage/lmgr/predicate.c
@@ -1677,8 +1677,9 @@ RegisterSerializableTransactionInt(Snapshot snapshot)
 			 othersxact != NULL;
 			 othersxact = NextPredXact(othersxact))
 		{
-			if (!SxactIsOnFinishedList(othersxact) &&
-				!SxactIsReadOnly(othersxact))
+			if (!SxactIsCommitted(othersxact)
+				&& !SxactIsDoomed(othersxact)
+				&& !SxactIsReadOnly(othersxact))
 			{
 				SetPossibleUnsafeConflict(sxact, othersxact);
 			}

Original file line number	Diff line number	Diff line change
`@@ -1677,8 +1677,9 @@ RegisterSerializableTransactionInt(Snapshot snapshot)`
`1677`	`1677`	`othersxact != NULL;`
`1678`	`1678`	`othersxact = NextPredXact(othersxact))`
`1679`	`1679`	`{`
`1680`		`- if (!SxactIsOnFinishedList(othersxact) &&`
`1681`		`- !SxactIsReadOnly(othersxact))`
	`1680`	`+ if (!SxactIsCommitted(othersxact)`
	`1681`	`+ && !SxactIsDoomed(othersxact)`
	`1682`	`+ && !SxactIsReadOnly(othersxact))`
`1682`	`1683`	`{`
`1683`	`1684`	`SetPossibleUnsafeConflict(sxact, othersxact);`
`1684`	`1685`	`}`