From: Tom Lane <tgl@sss.pgh.pa.us>
To: Scott Cain <cain@cshl.org>
Cc: PgSQL Performance ML <pgsql-performance@postgresql.org>
Cc: pgsql-sql@postgresql.org
Subject: Re: [SQL] EXTERNAL storage and substring on long strings
Date: Mon, 04 Aug 2003 11:53:43 -0400
Message-ID: <3574.1060012423@sss.pgh.pa.us> (raw)
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Scott Cain <cain@cshl.org> writes:
> At least this appears to work and is much faster, completing substring
> operations like above in about 0.27 secs (that's about two orders of
> magnitude improvement!)
I find it really, really hard to believe that a crude reimplementation
in plpgsql of the TOAST concept could beat the built-in implementation
at all, let alone beat it by two orders of magnitude.
Either there's something unrealistic about your testing of the
dna_string function, or your original tests are not causing TOAST to be
invoked in the expected way, or there's a bug we need to fix. I'd
really like to see some profiling of the poor-performing
external-storage case, so we can figure out what's going on.
regards, tom lane
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To: pgsql-sql@postgresql.org
Cc: tgl@sss.pgh.pa.us, cain@cshl.org, pgsql-performance@postgresql.org
Subject: Re: [SQL] EXTERNAL storage and substring on long strings
In-Reply-To: <3574.1060012423@sss.pgh.pa.us>
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