Re: Page Scan Mode in Hash Index

Hi Amit,

On Wed, Aug 23, 2017 at 5:08 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> On Tue, Aug 22, 2017 at 7:24 PM, Ashutosh Sharma <ashu(dot)coek88(at)gmail(dot)com> wrote:
>> On Tue, Aug 22, 2017 at 3:55 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>>
>> Okay, I got your point now. I think, currently in _hash_kill_items(),
>> if an overflow page is pinned we do not check if it got modified since
>> the last read or
>> not. Hence, if the vacuum runs on an overflow page that is pinned and
>> also has some dead tuples in it then it could create a problem for
>> scan basically,
>> when scan would attempt to mark the killed items as dead. To get rid
>> of such problem, i think, even if an overflow page is pinned we should
>> check if it got
>> modified or not since the last read was performed on the page. If yes,
>> then do not allow scan to mark killed items as dead. Attached is the
>> newer version with these changes along with some other cosmetic
>> changes mentioned in your earlier email. Thanks.
>>
>
> Thanks for the new version. I again looked at the patches and fixed
> quite a few comments in the code and ReadMe. You have forgotten to
> update README for the changes in vacuum patch
> (0003-Improve-locking-startegy-during-VACUUM-in-Hash-Index_v7). I
> don't have anything more to add. If you are okay with changes, then
> we can move it to Ready For Committer unless someone else has some
> more comments.
>

Thanks for reviewing my patches. I've gone through the changes done by
you in the README file and few changes in code comments. The changes
looks valid to me. But, it seems like there are some more minor review
comments from Jesper which i will fix and share the new set of patches
shortly.

--
With Regards,
Ashutosh Sharma
EnterpriseDB:http://www.enterprisedb.com