Re: Low performance on Windows problem

From: Dalibor Sramek <dali(at)insula(dot)cz>
To: Merlin Moncure <merlin(dot)moncure(at)rcsonline(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Low performance on Windows problem
Date: 2005-09-13 13:49:51
Message-ID: 20050913134951.GA53837@www.epot.cz
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On Tue, Sep 13, 2005 at 07:58:20AM -0400, Merlin Moncure wrote:
> Can you give specific examples of cases that are not performing like you
> expect? If possible, give a few queries with explain analyze times and
> all that.

O.K. I have found one particular problem:

2005-09-13 14:43:02 LOG: statement: declare SQL_CUR03949008 cursor for
SELECT * FROM t_umlpattern
2005-09-13 14:43:02 LOG: duration: 0.000 ms
2005-09-13 14:43:02 LOG: statement: fetch 1000 in SQL_CUR03949008
2005-09-13 14:43:22 LOG: duration: 20185.000 ms

This command is executed while a model is loaded from the repository.

The table definition is:
CREATE TABLE t_umlpattern (
PatternID INTEGER DEFAULT nextval('"patternid_seq"'::text) NOT NULL
PRIMARY KEY,
PatternCategory VARCHAR(100),
PatternName VARCHAR(150),
Style VARCHAR(250),
Notes TEXT,
PatternXML TEXT,
Version VARCHAR(50)
);

It has just 23 rows but the PatternXML column is rather large. The table
dump has over 900 kB.

Now
select * from t_umlpattern limit 2

takes 1500+ msec on the Windows machine and 60 on a comparable Linux
machine. Both selects performed from remote PgAdmin.
The same select performed localy on the windows machine takes 60 msec.

So I guess the problem is in the transfer of the bigger amount of data from
the Windows server.

I put the dump at http://www.insula.cz/dali/misc/table.zip

Could anybody confirm the difference?

Thanks for any suggestions.

Dalibor Sramek

--
Dalibor Sramek http://www.insula.cz/dali \ In the eyes of cats
/ dalibor(dot)sramek(at)insula(dot)cz \ all things
/ >H blog http://www.transhumanismus.cz/blog.php \ belong to cats.

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