Re: heap_lock_updated_tuple_rec can leak a buffer refcount

On Tue, Feb 13, 2018 at 10:11 AM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> It seems to me that heap_lock_updated_tuple_rec can lead to a buffer
> refcount leak while locking an updated tuple by an aborted
> transaction. In commit - 5c609a74, we have added the code to deal
> with aborted transactions as below:
>
> heap_lock_updated_tuple_rec()
> {
> ..
>
> if (PageIsAllVisible(BufferGetPage(buf)))
> visibilitymap_pin(rel, block, &vmbuffer);
> else
> vmbuffer = InvalidBuffer;
>
> LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
> ..
> -------------------------- below code is added by commit -5c609a74 -----------
> if (TransactionIdDidAbort(HeapTupleHeaderGetXmin(mytup.t_data)))
> {
> UnlockReleaseBuffer(buf);
> return HeapTupleMayBeUpdated;
> }
> -------------------------------------------------------------
>
> I think the above code forgets to deal with vmbuffer and can lead to a
> leak of the same. Attached patch ensures that it deals with vmbuffer
> when required.
>

Registered the patch for next CF:
https://commitfest.postgresql.org/17/1531/

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com