Re: again on index usage - Mailing list pgsql-hackers

From Daniel Kalchev
Subject Re: again on index usage
Date
Msg-id 200201101137.NAA00235@dcave.digsys.bg
Whole thread Raw
In response to Re: again on index usage  ("Zeugswetter Andreas SB SD" <ZeugswetterA@spardat.at>)
List pgsql-hackers
>>>"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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