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Re: Re: patch submission: truncate trailing nulls from heap rows to reduce the size of the null bitmap [Review]

From: Simon Riggs <simon(at)2ndQuadrant(dot)com>
To: Amit Kapila <amit(dot)kapila(at)huawei(dot)com>
Cc: Kevin Grittner <kgrittn(at)mail(dot)com>, robertmhaas(at)gmail(dot)com, josh(at)agliodbs(dot)com, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Re: patch submission: truncate trailing nulls from heap rows to reduce the size of the null bitmap [Review]
Date: 2013-01-09 12:14:34
Message-ID: (view raw or whole thread)
Lists: pgsql-hackers
On 9 January 2013 12:06, Amit Kapila <amit(dot)kapila(at)huawei(dot)com> wrote:
> On Wednesday, January 09, 2013 4:52 PM Simon Riggs wrote:
>> On 24 December 2012 16:57, Amit Kapila <amit(dot)kapila(at)huawei(dot)com> wrote:
>> > Performance: Average of 3 runs of pgbench in tps
>> > 9.3devel  |  with trailing null patch
>> > ----------+--------------------------
>> > 578.9872  |   573.4980
>> On balance, it would seem optimizing for this special case would
>> affect everybody negatively; not much, but enough. Which means we
>> should rekect this patch.
>> Do you have a reason why a different view might be taken?
> I have tried to dig why this gap is coming. I have observed that there is
> very less change in normal path.
> I wanted to give it some more time to exactly find if something can be done
> to avoid performance dip in normal execution.
> Right now I am busy in certain other work. But definitely in coming week or
> so, I shall spare time to work on it again.

Perhaps. Not every idea produces useful outcomes. Even after your
excellent research, it appears we haven't made this work yet. It's a
shame. Should we invest more time? It's considered rude to advise
others how to spend their time, but let me say this: we simply don't
have enough time to do everything and we need to be selective,
prioritising our time on to the things that look to give the best

 Simon Riggs         
 PostgreSQL Development, 24x7 Support, Training & Services

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