| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | "Simon Riggs" <simon(at)2ndquadrant(dot)com> |
| Cc: | "Jignesh K(dot) Shah" <J(dot)K(dot)Shah(at)Sun(dot)COM>, "Josh Berkus" <josh(at)agliodbs(dot)com>, pgsql-performance(at)postgresql(dot)org, "Alvaro Herrera" <alvherre(at)commandprompt(dot)com> |
| Subject: | Re: User concurrency thresholding: where do I look? |
| Date: | 2007-07-23 16:35:28 |
| Message-ID: | 27521.1185208528@sss.pgh.pa.us |
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| Lists: | pgsql-performance |
"Simon Riggs" <simon(at)2ndquadrant(dot)com> writes:
> Well, I discover there is an allocation of 8232 (inflation...) made once
> per statement by a memory context called... ExecutorState. Still not
> sure exactly which allocation this is, but its definitely once per
> statement on pgbench, which should narrow it down. Plan, query etc?
Are you working with stock sources? The only allocation exceeding 1K
that I can see during pgbench is BTScanOpaqueData, which is 6600 bytes.
(Checked by setting a conditional breakpoint on AllocSetAlloc.) The
path that allocates a single-chunk block is never taken at all.
regards, tom lane
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