On Thu, 8 Apr 2010, Robert Haas wrote:
On Thu, Apr 8, 2010 at 2:53 PM, Alvaro Herrera
<alvhe...@commandprompt.com> wrote:
Oleg Bartunov wrote:
our client complained about slow query, which involves temporary tables.
Analyzing them manually solved the problem. I don't remember
arguments against temporary tables support by autovacuum. I'd
appreciate any
pointers.
Autovacuum can't process temp tables; they could reside in a backend's
private temp buffers (local memory, not shared).
On general thought I've had is that it would be nice if the first
attempt to SELECT against a table with no statistics would trigger an
automatic ANALYZE by the backend on which the query was executed.
It's pretty common to populate a table using INSERT, or CTAS, or COPY
and then try to immediately run a query against it, and I've often
found that it's necessary to insert manual analyze statements in there
to get decent query plans.
Oracle does this. So, is't worth to add support (configurable, like
Oracle's optimizer_dynamic_sampling) ?
Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: o...@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83
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