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Re: Slow response from 'SELECT * FROM table'

From: "Josh Berkus" <josh(at)agliodbs(dot)com>
To: Jirka Novak <j(dot)novak(at)netsystem(dot)cz>,pgsql-performance(at)postgresql(dot)org
Subject: Re: Slow response from 'SELECT * FROM table'
Date: 2002-11-11 17:28:04
Message-ID: web-1821126@davinci.ethosmedia.com (view raw or flat)
Thread:
Lists: pgsql-performance
Jirka,

>   I have table with 30 columns and 30000..500000 rows. When I make 
> 'SELECT * FROM table' postgresql start doing something and return
> first row after 10s (for 30k rows) and after 5min (500k rows). It
> looks like it copy whole response to temp space and after that it
> shows it.
>   I don't know why. I tested same table structure and datas on Oracle
> 
> and MSSQL and both returned first row immediatly.
>   Have someone any idea?

I can think of any number of reasons why.   However, I need more detail
from you:

1) Why are you selecting 500,000 rows at once?

2) Is "SELECT * FROM table_a" the entirety of your query, or was there
more to it than that?

3) Are you talking about PSQL, or some other interface?

-Josh Berkus



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