Re: reading large BYTEA type is slower than expected

Tom,

Actually the 120 records I quoted is a mistake. Since it is a three band
image the number of records should be 360 records or 120 records for
each band.

Mark

-----Original Message-----
From: Tom Lane [mailto:tgl(at)sss(dot)pgh(dot)pa(dot)us]
Sent: Friday, May 18, 2007 10:48 AM
To: Mark Harris
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: [PERFORM] reading large BYTEA type is slower than expected

"Mark Harris" <mharris(at)esri(dot)com> writes:
> We have recently ported our application to the postgres database. For
> the most part performance has not been an issue; however there is one
> situation that is a problem and that is the initial read of rows
> containing BYTEA values that have an average size of 2 kilobytes or
> greater. For BYTEA values postgres requires as much 3 seconds to read
> the values from disk into its buffer cache.

How large is "large"?

(No, I don't believe it takes 3 sec to fetch a single 2Kb value.)

regards, tom lane