| From: | Simon Riggs <simon(at)2ndQuadrant(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>, Andrew Dunstan <andrew(at)dunslane(dot)net>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: lock contention on parallel COPY ? |
| Date: | 2008-09-26 18:27:46 |
| Message-ID: | 1222453666.4445.998.camel@ebony.2ndQuadrant |
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| Lists: | pgsql-hackers |
On Fri, 2008-09-26 at 14:00 -0400, Tom Lane wrote:
> Simon Riggs <simon(at)2ndQuadrant(dot)com> writes:
> > Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc> writes:
> >> samples % symbol name
> >> 55526 16.5614 LWLockAcquire
> >> 29721 8.8647 DoCopy
> >> 26581 7.9281 CopyReadLine
> >> 25105 7.4879 LWLockRelease
> >> 15743 4.6956 PinBuffer
> >> 14725 4.3919 heap_formtuple
>
> > Probably loading a table with a generated PK or loading data in
> > ascending sequence, so its contending heavily for the rightmost edge of
> > the index.
>
> No, given that DoCopy and CopyReadLine are right up there, I think we're
> still looking at the COPY phase, not index building.
>
> The profile will probably change completely once index building
> starts...
Sorry, was assuming we were loading with indexes on, which is wrong.
Agree the profile looks odd.
--
Simon Riggs www.2ndQuadrant.com
PostgreSQL Training, Services and Support
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