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Very slow bytea extraction

From: "msmbarabino(at)virgilio(dot)it" <msmbarabino(at)virgilio(dot)it>
To: pgsql-bugs(at)postgresql(dot)org
Subject: Very slow bytea extraction
Date: 2007-03-21 18:00:27
Message-ID: 11175a82d60.msmbarabino@virgilio.it (view raw or flat)
Thread:
Lists: pgsql-bugs
Hi,
before writing to this list I've tried to solve the problem 
discussing it in the pgsql-performance mailing list but I wasn't able 
to solve it.

The problem is as follows.

My test db only contains a 
single table with some varying-text field and a bytea field.
When 
inserting data into this table everyting works fine.
The problem is 
that it takes too much time for the db to answer a simple select query 
on the bytea field.
The test table has 36 records and each bytea field 
contains a 250KB object. A (SELECT byteafield FROM table) takes more 
than 1 minute to execute.

The table is called FILE

Here is the output 
of explain analyze SELECT * FROM "FILE"

"Seq Scan on "FILE" (cost=0.
00..1.36 rows=36 width=235)
(actual time=0.023..0.107 rows=36 loops=1) 
Total runtime:0.337 ms".

I'm accessing the db with jdbc but the 
problem persists even with psql or pgAdmin.

Postgresql version: 8.2.3

OS: WIN XP (32-bit)

Thanks in advance for your help

Massimo

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