From: Daniel Kalchev <daniel@digsys.bg>
To: Zeugswetter Andreas SB SD <ZeugswetterA@spardat.at>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-hackers@postgresql.org
Subject: Re: again on index usage
Date: Thu, 10 Jan 2002 13:37:41 +0200
Message-ID: <200201101137.NAA00235@dcave.digsys.bg> (raw)
In-Reply-To: <46C15C39FEB2C44BA555E356FBCD6FA41EB499@m0114.s-mxs.net>
>>>"Zeugswetter Andreas SB SD" said:
> What is actually estimated wrong here seems to be the estimated
> effective cache size, and thus the cache ratio of page fetches.
> Most of your pages will be cached.
>
> The tuning parameter is: effective_cache_size
>
> With (an estimated) 50 % of 512 Mb for file caching that number would
> need to be:
> effective_cache_size = 32768 # 8k pages
>
> Can you try this and tell us what happens ?
I suspected this, but haven't really come to test it. On BSD/OS, the buffer
cache is 10% of the RAM, in my case
buffer cache = 53522432 (51.04 MB)
I guess effective_cache_size = 6400 will be ok.
Daniel
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To: pgsql-hackers@postgresql.org
Cc: daniel@digsys.bg, ZeugswetterA@spardat.at, tgl@sss.pgh.pa.us
Subject: Re: again on index usage
In-Reply-To: <200201101137.NAA00235@dcave.digsys.bg>
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