Re: [PERFORM] EXPLAIN ANALYZE on 8.2 - Mailing list pgsql-hackers

From Gregory Stark
Subject Re: [PERFORM] EXPLAIN ANALYZE on 8.2
Date
Msg-id 87irgdiccg.fsf@enterprisedb.com
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In response to Re: [PERFORM] EXPLAIN ANALYZE on 8.2  (Martijn van Oosterhout <kleptog@svana.org>)
Responses Re: [PERFORM] EXPLAIN ANALYZE on 8.2  (Martijn van Oosterhout <kleptog@svana.org>)
Re: [PERFORM] EXPLAIN ANALYZE on 8.2  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
"Martijn van Oosterhout" <kleptog@svana.org> writes:

> BTW, doing gettimeofday() without kernel entry is not really possible.

That's too strong a conclusion. Doing gettimeofday() without some help from
the kernel isn't possible but it isn't necessary to enter the kernel for each
call.

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). 

--  Gregory Stark EnterpriseDB          http://www.enterprisedb.com


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