Re: patch: tsearch - some memory diet

Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>

From: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
To: Teodor Sigaev <teodor@sigaev.ru>
Cc: Pavel Stehule <pavel.stehule@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2010-09-07T16:42:34Z
Lists: pgsql-hackers
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