| From: | Maciek Sakrejda <msakrejda(at)truviso(dot)com> |
|---|---|
| To: | Tomas Vondra <tv(at)fuzzy(dot)cz> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: SORT performance - slow? |
| Date: | 2011-05-23 17:01:42 |
| Message-ID: | BANLkTi=g+xaY_2cWqPCBS5=aKdHtfOWsVw@mail.gmail.com |
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| Lists: | pgsql-performance |
> You're probably reading it wrong. The sort itself takes about 1 ms (just
> subtract the numbers in "actual=").
I thought it was cost=startup_cost..total_cost. That is not quite the
same thing, since startup_cost is effectively "cost to produce first
row", and Sort can't really operate in a "streaming" fashion (well,
theoretically, something like selection sort could, but that's beside
the point) so it needs to do all the work up front. I'm no explain
expert, so someone please correct me if I'm wrong.
---
Maciek Sakrejda | System Architect | Truviso
1065 E. Hillsdale Blvd., Suite 215
Foster City, CA 94404
(650) 242-3500 Main
www.truviso.com
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