Re: patch: tsearch - some memory diet

From: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
To: Teodor Sigaev <teodor(at)sigaev(dot)ru>
Cc: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: patch: tsearch - some memory diet
Date: 2010-09-07 16:42:34
Message-ID: 4C866B7A.5000006@enterprisedb.com
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On 07/09/10 19:27, Teodor Sigaev wrote:
>> on 32bit from 27MB (3399 blocks) to 13MB (1564 blocks)
>> on 64bit from 55MB to cca 27MB.
>
> Good results. But, I think, there are more places in ispell to use
> hold_memory():
> - affixes and affix tree
> - regis (REGex for ISpell, regis.c)

A more general solution would be to have a new MemoryContext
implementation that does the same your patch does. Ie. instead of
tracking each allocation, just allocate a big chunk, and have palloc()
return the next n free bytes from it, like a stack. pfree() would
obviously not work, but wholesale MemoryContextDelete of the whole
memory context would.

I remember I actually tried this years ago, trying to reduce the
overhead of parsing IIRC. The parser also does a lot of small
allocations that are not individually pfree'd. And I think it helped a
tiny bit, but I didn't pursue it further. But if there's many places
where it would help, then it might well be worth it.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com

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