Re: Write Ahead Logging for Hash Indexes

Amit Kapila <amit.kapila16@gmail.com>

From: Amit Kapila <amit.kapila16@gmail.com>

To: Robert Haas <robertmhaas@gmail.com>

Cc: Jesper Pedersen <jesper.pedersen@redhat.com>, Jeff Janes <jeff.janes@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>

Date: 2017-02-13T15:22:09Z

Lists: pgsql-hackers

Attachments

0001-Expose-a-new-API-_hash_pgaddmultitup-to-add-multiple.patch (application/octet-stream) patch 0001
0002-Expose-hashinitbitmapbuffer-to-initialize-bitmap-pag.patch (application/octet-stream) patch 0002
0003-Restructure-_hash_addovflpage-so-that-the-operation-.patch (application/octet-stream) patch 0003
0004-restructure-split-bucket-code-so-that-the-operation-.patch (application/octet-stream) patch 0004
0005-Restructure-hash-index-creation-and-metapage-initial.patch (application/octet-stream) patch 0005
0006-Enable-WAL-for-Hash-Indexes.patch (application/octet-stream) patch 0006

On Fri, Feb 10, 2017 at 12:15 PM, Amit Kapila <amit.kapila16@gmail.com> wrote:
> On Thu, Feb 9, 2017 at 10:28 PM, Robert Haas <robertmhaas@gmail.com> wrote:
>
>> The things that look like preliminary refactoring to
>> me are:
>>
>> - Adding _hash_pgaddmultitup and using it in various places.
>> - Adding and freeing overflow pages has been extensively reworked.
>>
>
> Freeing the overflow page is too tightly coupled with changes related
> to _hash_pgaddmultitup, so it might be better to keep it along with
> it.  However, I think we can prepare a separate patch for changes
> related to adding the overflow page.
>
>> - Similarly, there is some refactoring of how bitmap pages get initialized.
>> - Index initialization has been rejiggered significantly.
>> - Bucket splits have been rejiggered.
>>
>

As discussed, attached are refactoring patches and a patch to enable
WAL for the hash index on top of them.



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

Commits

Add a regression test for snapshot too old with hash indexes.
- 42bdaebf1618 10.0 landed
hash: Add write-ahead logging support.
- c11453ce0aea 10.0 landed
Improve coding in _hash_addovflpage.
- e898437460f5 10.0 cited
Remove _hash_wrtbuf() in favor of calling MarkBufferDirty().
- 25216c989384 10.0 cited
Improve hash index bucket split behavior.
- 6d46f4783efe 10.0 cited