From: Tom Lane <tgl@sss.pgh.pa.us>
To: Rainer Mager <rainer@vanten.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: difficulties with time based queries
Date: Sun, 05 Apr 2009 21:33:17 -0400
Message-ID: <7371.1238981597@sss.pgh.pa.us> (raw)
In-Reply-To: <003501c9b656$a9c73fe0$fd55bfa0$@com>
References: <003001c9b645$e8a7cec0$b9f76c40$@com>
<e7f9235d0904051646j7e8374afncf79e3708ae40c20@mail.gmail.com>
<003501c9b656$a9c73fe0$fd55bfa0$@com>
"Rainer Mager" <rainer@vanten.com> writes:
>> From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
>> Hmm ... it's pretty unusual to see the index fetch portion of a bitmap
>> scan take the bulk of the runtime. Usually that part is fast and where
>> the pain comes is in fetching from the heap. I wonder whether that
>> index has become bloated. How big are the table and the index
>> physically? (Look at pg_class.relpages, or if you want a really
>> accurate number try pg_relation_size().)
> Can you give me some more info on how to look at these stats?
Since you've got 8.3 it's easy: select pg_relation_size('tablename')
(or indexname). The result is in bytes, so you might want to
divide by 1K or 1M to keep the number readable.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, rainer@vanten.com
Subject: Re: difficulties with time based queries
In-Reply-To: <7371.1238981597@sss.pgh.pa.us>
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