| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov> |
| Cc: | "Robert Haas" <robertmhaas(at)gmail(dot)com>, JPalmer(at)linz(dot)govt(dot)nz, pgsql-performance(at)postgresql(dot)org, andy(at)squeakycode(dot)net |
| Subject: | Re: Possible to improve query plan? |
| Date: | 2011-01-24 17:33:34 |
| Message-ID: | 9658.1295890414@sss.pgh.pa.us |
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| Lists: | pgsql-performance |
"Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov> writes:
> Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>> But isn't 13.5 seconds awfully slow to scan 149557 rows? The sort
>> is sorting 23960kB. Dividing that by 149557 rows gives ~169
>> bytes/per row
> You're right. I would expect 9 ms as per tuple as a worst case if
> it doesn't need to go to TOAST data. Caching, multiple rows per
> page, or adjacent pages should all tend to bring it down from there.
> How does it get to 90 ms per row with rows that narrow?
Um, that looks like 90 usec per row, not msec.
regards, tom lane
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