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Re: Effective limit on size of text type?

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: eric soroos <eric-psql(at)soroos(dot)net>
Cc: pgsql-novice(at)postgresql(dot)org
Subject: Re: Effective limit on size of text type?
Date: 2002-08-08 02:30:02
Message-ID: 28712.1028773802@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-novice
eric soroos <eric-psql(at)soroos(dot)net> writes:
> test=# select _incomingEnclosures from dl_event where _idNum=3010;
> Takes at least a couple of minutes, either through psql or a libpq based connection.   
> test=# select char_length(_incomingEnclosures) from dl_event where _donorNum=804 and _responseNum=3010;
> -[ RECORD 1 ]-------
> char_length | 952478
> Is nearly immediate.

Given that those queries aren't using comparable WHERE conditions, I'd
wonder about the query plan myself, not the size of the returned data
item.  Do you have an index on _idNum?  Is it getting used?

In a quick test here, selecting a 1MB text value into a file, using

regression=# select f1 from foo
regression-# \g tmpfile

took about a tenth of a second...

			regards, tom lane

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