Re: Page Scan Mode in Hash Index

From: Ashutosh Sharma <ashu(dot)coek88(at)gmail(dot)com>
To: Jesper Pedersen <jesper(dot)pedersen(at)redhat(dot)com>
Cc: pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Page Scan Mode in Hash Index
Date: 2017-03-23 18:11:29
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On Thu, Mar 23, 2017 at 8:29 PM, Jesper Pedersen
<jesper(dot)pedersen(at)redhat(dot)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

Attachment Content-Type Size
0001-Rewrite-hash-index-scans-to-work-a-page-at-a-timev3.patch application/x-patch 23.7 KB

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