Re: That EXPLAIN ANALYZE patch still needs work - Mailing list pgsql-hackers

On Thu, 2006-06-08 at 17:21 -0400, Tom Lane wrote:
> Alvaro Herrera <alvherre@commandprompt.com> writes:
> > Tried on two machines.  The first (Turion64 laptop) gives 44-45 ms for
> > the SELECT, and 50-51 ms for the EXPLAIN ANALYZE.
> 
> > The second machine, desktop Celeron 533, gives 197-200 ms for the SELECT
> > and 788-790 for the EXPLAIN ANALYZE.  I guess this is the reproduction
> > you were looking for.
> 
> Do you have oprofile installed on these?  Comparing oprofile results
> might give some more insight where the time is going.

On my office PC the overhead from EA is about 20%.

stracing a backend, I also notice that on a 1.5 million row table we
make only 39158 calls to gettimeofday, on a table of 24591 blocks.

I'm thinking that the instrumentation overhead has been reduced as a
result of the page-at-a-time heap scans we now have?

--  Simon Riggs              EnterpriseDB   http://www.enterprisedb.com