From: "Alban Médici (NetCentrex)" <amedici@fr.netcentrex.net>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-benchmarks@postgresql.org
Cc: pgsql-performance@postgresql.org
Subject: Re: [PERFORM] stats on cursor and query execution troubleshooting
Date: Fri, 08 Oct 2004 10:47:42 +0200
Message-ID: <4166542E.2020809@fr.netcentrex.net> (raw)
In-Reply-To: <25576.1097072199@sss.pgh.pa.us>
References: <4163C5C3.3030304@fr.netcentrex.net>
<25576.1097072199@sss.pgh.pa.us>
Thanks for your repply, but I still don"t understand why the statistic
logs :
! 0/0 [0/0] filesystem blocks in/out
it told me there is no hard disk access, I'm sure there is, I heard my
HDD, and see activity using gkrellm (even using my first query ; big
select *) ?
2004-10-08 10:40:05 DEBUG: query: select * from "LINE_Line";
2004-10-08 10:40:53 DEBUG: QUERY STATISTICS
! system usage stats:
! 48.480196 elapsed 42.010000 user 0.700000 system sec
! [42.030000 user 0.720000 sys total]
! 0/0 [0/0] filesystem blocks in/out
! 6/23 [294/145] page faults/reclaims, 0 [0] swaps
! 0 [0] signals rcvd, 0/0 [0/0] messages rcvd/sent
! 0/0 [0/0] voluntary/involuntary context switches
! postgres usage stats:
! Shared blocks: 3902 read, 0 written, buffer hit
rate = 11.78%
! Local blocks: 0 read, 0 written, buffer hit
rate = 0.00%
! Direct blocks: 0 read, 0 written
looking at the web some logs, I saw those fields filled (i/o filesystem)
Does my postgresql.conf missing an option or is therer a known bug of my
postgresql server 7.2.4 ?
thx
regards
Alban Médici
on 06/10/2004 16:16 Tom Lane said the following:
>=?ISO-8859-1?Q?=22Alban_M=E9dici_=28NetCentrex=29=22?= <amedici@fr.netcentrex.net> writes:
>
>
>>I'm looking for the statistic of memory, CPU, filesystem access while=20
>>executing some regular SQL query, and I want to compare them to
>>same kind of results while executing a cursor function.
>>
>>
>
>I think your second query is finding all the disk pages it needs in
>kernel disk cache, because they were all read in by the first query.
>This has little to do with cursor versus non cursor, and everything
>to do with hitting recently-read data again.
>
> regards, tom lane
>
>
>
--
Alban Médici
R&D software engineer
------------------------------
you can contact me @ :
http://www.netcentrex.net
------------------------------
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To: pgsql-benchmarks@postgresql.org
Cc: amedici@fr.netcentrex.net, tgl@sss.pgh.pa.us, pgsql-performance@postgresql.org
Subject: Re: [PERFORM] stats on cursor and query execution troubleshooting
In-Reply-To: <4166542E.2020809@fr.netcentrex.net>
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