Re: gettimeofday is at the end of its usefulness?

On Tue, May 13, 2014 at 06:58:11PM -0400, Tom Lane wrote:
> A recent question from Tim Kane prompted me to measure the overhead
> costs of EXPLAIN ANALYZE, which I'd not checked in awhile. Things
> are far worse than I thought. On my current server (by no means
> lavish hardware: Xeon E5-2609 @2.40GHz) a simple seqscan can run
> at something like 110 nsec per row:

I assume you ran pg_test_timing too:

Testing timing overhead for 3 seconds.
Per loop time including overhead: 41.70 nsec
Histogram of timing durations:
< usec % of total count
1 95.83035 68935459
2 4.16923 2999133
4 0.00037 268
8 0.00004 31
16 0.00000 1
32 0.00000 1

My overhead of 41.70 nsec matches yours.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

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