Re: Page Scan Mode in Hash Index

Ashutosh Sharma <ashu.coek88@gmail.com>

From: Ashutosh Sharma <ashu.coek88@gmail.com>
To: Jesper Pedersen <jesper.pedersen@redhat.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2017-03-23T18:11:29Z
Lists: pgsql-hackers

Attachments

On Thu, Mar 23, 2017 at 8:29 PM, Jesper Pedersen
<jesper.pedersen@redhat.com> wrote:
> Hi,
>
> On 03/22/2017 09:32 AM, Ashutosh Sharma wrote:
>>
>> Done. Please refer to the attached v2 version of patch.
>>
>
> Thanks.
>
>>>> 1) 0001-Rewrite-hash-index-scans-to-work-a-page-at-a-time.patch: this
>>>> patch rewrites the hash index scan module to work in page-at-a-time
>>>> mode. It basically introduces two new functions-- _hash_readpage() and
>>>> _hash_saveitem(). The former is used to load all the qualifying tuples
>>>> from a target bucket or overflow page into an items array. The latter
>>>> one is used by _hash_readpage to save all the qualifying tuples found
>>>> in a page into an items array. Apart from that, this patch bascially
>>>> cleans _hash_first(), _hash_next and hashgettuple().
>>>>
>
> 0001v2:
>
> In hashgettuple() you can remove the 'currItem' and 'offnum' from the 'else'
> part, and do the assignment inside
>
>   if (so->numKilled < MaxIndexTuplesPerPage)
>
> instead.
>

Done. Please have a look into the attached v3 patch.

>
> No new comments for 0002 and 0003.

okay. Thanks.

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

Commits

  1. Remove lsn from HashScanPosData.

  2. Fix trivial mistake in README.

  3. hash: Implement page-at-a-time scan.

  4. Reduce pinning and buffer content locking for btree scans.