Re: Reviewing freeze map code

On Tue, Jun 7, 2016 at 10:10 PM, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>
wrote:
>
> Thank you for implementing the patch.
>
> I've not test it deeply but here are some comments.
> This check tool only checks if the frozen page has live-unfrozen tuple.
> That is, it doesn't care in case where the all-frozen page mistakenly
> has dead-frozen tuple.
>

Do you mean to say that we should have a check for ItemIdIsDead() and then
if item is found to be dead, then add it to array of non_frozen items? If
so, earlier I thought we might not need this check as we are already using
heap_tuple_needs_eventual_freeze(), but now again looking at it, it seems
wise to check for dead items separately as those won't be covered by other
check.

>
> + /* Clean up. */
> + if (vmbuffer != InvalidBuffer)
> + ReleaseBuffer(vmbuffer);
>
> I think that we should use BufferIsValid() here.
>

We can use BufferIsValid() as well, but I am trying to be consistent with
nearby code, refer collect_visibility_data(). We can change at all places
together if people prefer that way.

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