Re: BUG #5952: SetRWConflict assertion failure

On Sun, Mar 27, 2011 at 3:18 PM, Kevin Grittner
<Kevin.Grittner@wicourts.gov> wrote:
> "YAMAMOTO Takashi" =A0wrote:
>
>> Description: SetRWConflict assertion failure
>
>> SerializableXactHashLock relocking in CheckTargetForConflictsIn()
>> seems racy to me.
>
> You're right. =A0The attached patch should fix the assertion you hit.

This patch looks reasonable, but I'm a bit concerned about the chunk
immediately preceding the patched area.

When we do this:

                    LWLockRelease(SerializableXactHashLock);
                    LWLockRelease(partitionLock);
                    LWLockRelease(SerializablePredicateLockListLock);
                    LWLockAcquire(partitionLock, LW_SHARED);
                    LWLockAcquire(SerializableXactHashLock, LW_SHARED);

Don't we need to also reset nextpredlock to the head of the list?  I'm
assuming it's the partitionLock that's keeping the PREDICATELOCKs from
bouncing out from under us, so if we release it, aren't we potentially
point off into thin air?

--=20
Robert Haas
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