Re: gettimeofday is at the end of its usefulness? - Mailing list pgsql-hackers

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 nsecHistogram 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@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
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