Re: [REVIEW] Re: Compression of full-page-writes

From: Abhijit Menon-Sen <ams(at)2ndQuadrant(dot)com>
To: Rahila Syed <rahilasyed90(at)gmail(dot)com>
Cc: Rahila Syed <rahilasyed(dot)90(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
Subject: Re: [REVIEW] Re: Compression of full-page-writes
Date: 2014-06-18 12:55:34
Message-ID: 20140618125534.GA18575@toroid.org
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At 2014-06-18 18:10:34 +0530, rahilasyed90(at)gmail(dot)com wrote:
>
> palloc() is disallowed in critical sections and we are already in CS
> while executing this code. So we use malloc().

Are these allocations actually inside a critical section? It seems to me
that the critical section starts further down, but perhaps I am missing
something.

Second, as Andres says, you shouldn't malloc() inside a critical section
either; and anyway, certainly not without checking the return value.

> I am not sure if the change will be a significant improvement from
> performance point of view except it will save few condition checks.

Moving that allocation out of the outer for loop it's currently in is
*nothing* to do with performance, but about making the code easier to
read.

-- Abhijit

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