| From: | Martijn van Oosterhout <kleptog(at)svana(dot)org> |
|---|---|
| To: | Gregory Stark <stark(at)enterprisedb(dot)com> |
| Cc: | Simon Riggs <simon(at)2ndquadrant(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Kelly Burkhart <kelly(dot)burkhart(at)gmail(dot)com>, Evgeny Gridasov <eugrid(at)fpm(dot)kubsu(dot)ru>, pgsql-performance(at)postgresql(dot)org, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: [HACKERS] EXPLAIN ANALYZE on 8.2 |
| Date: | 2006-12-15 12:24:52 |
| Message-ID: | 20061215122452.GI958@svana.org |
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| Lists: | pgsql-hackers pgsql-performance |
On Fri, Dec 15, 2006 at 12:15:59PM +0000, Gregory Stark wrote:
> There are various attempts at providing better timing infrastructure at low
> overhead but I'm not sure what's out there currently. I expect to do this what
> we'll have to do is invent a pg_* abstraction that has various implementations
> on different architectures. On Solaris it can use DTrace internally, on Linux
> it might have something else (or more likely several different options
> depending on the age and config options of the kernel).
I think we need to move to a sampling approach. setitimer is good,
except it doesn't tell you if signals have been lost. Given they are
most likely to be lost during high disk I/O, they're actually
significant. I'm trying to think of a way around that. Then you don't
need a cheap gettimeofday at all...
Have a nice day,
--
Martijn van Oosterhout <kleptog(at)svana(dot)org> http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.
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