Re: Write Ahead Logging for Hash Indexes

From: Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
To: Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
Cc: Jesper Pedersen <jesper(dot)pedersen(at)redhat(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Write Ahead Logging for Hash Indexes
Date: 2016-11-09 14:10:31
Message-ID: CAA4eK1LsqbCejPzRfcO_UNeuMx6NAp7nmVr+-OWNKGQ8L6Ky_Q@mail.gmail.com
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On Tue, Nov 8, 2016 at 10:56 PM, Jeff Janes <jeff(dot)janes(at)gmail(dot)com> wrote:
> On Sat, Sep 24, 2016 at 10:00 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
> wrote:
>>
>> On Fri, Sep 23, 2016 at 5:34 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
>> wrote:
>> >
>> > I think here I am slightly wrong. For the full page writes, it do use
>> > RBM_ZERO_AND_LOCK mode to read the page and for such mode we are not
>> > doing page verification check and rather blindly setting the page to
>> > zero and then overwrites it with full page image. So after my fix,
>> > you will not see the error of checksum failure. I have a fix ready,
>> > but still doing some more verification. If everything passes, I will
>> > share the patch in a day or so.
>> >
>>
>> Attached patch fixes the problem, now we do perform full page writes
>> for bitmap pages. Apart from that, I have rebased the patch based on
>> latest concurrent index patch [1]. I have updated the README as well
>> to reflect the WAL logging related information for different
>> operations.
>>
>> With attached patch, all the review comments or issues found till now
>> are addressed.
>
>
> This needs to be updated to apply over concurrent_hash_index_v10.patch.
>
> Unless we want to wait until that work is committed before doing more review
> and testing on this.
>

The concurrent hash index patch is getting changed and some of the
changes needs change in this patch as well. So, I think after it gets
somewhat stabilized, I will update this patch as well. I am not sure
if it is good idea to update it with every version of hash index.

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

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