| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | "Dann Corbit" <DCorbit(at)connx(dot)com> |
| Cc: | "Steve Crawford" <scrawford(at)pinpointresearch(dot)com>, pgsql-performance(at)postgreSQL(dot)org, pgsql-hackers(at)postgreSQL(dot)org |
| Subject: | Re: Terrible performance on wide selects |
| Date: | 2003-01-23 00:04:02 |
| Message-ID: | 25521.1043280242@sss.pgh.pa.us |
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| Lists: | pgsql-hackers pgsql-performance |
"Dann Corbit" <DCorbit(at)connx(dot)com> writes:
> Maybe I don't really understand the problem, but it seems simple enough
> to do it once for the whole query.
We already do cache column offsets when they are fixed. The code that's
the problem executes when there's a variable-width column in the table
--- which means that all columns to its right are not at fixed offsets,
and have to be scanned for separately in each tuple, AFAICS.
regards, tom lane
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