On 7/5/2007 5:30 PM, Tom Lane wrote:
Jan Wieck <[EMAIL PROTECTED]> writes:
I think I've coded it in a way that if one doesn't use the \usleep command at all, it will never even call gettimeofday() and use a NULL timeout in select() as it used to.


Did you check that the observed performance for non-usleep-using scripts
didn't change?  If this extra overhead causes a reduction in reported
TPS rates it would make it hard to compare older and newer tests.

Given pgbench's unpredictability of results ... lets see.

I ran

    dropdb x
    createdb x
    pgbench -i -s10 x
    psql -c 'checkpoint' x
    sleep 1
    psql -c 'checkpoint' x
    pgbench -s10 -c5 -t10000 x
    pgbench -s10 -c5 -t10000 x
    pgbench -s10 -c5 -t10000 x

Original pgbench reported 39, 37 and 33 TPS. Having my patch applied it reported 40, 38 and 33 TPS. Inserting a "\usleep 1" after the update to accounts of a default equivalent script changed those numbers to 40, 37 and 33. I interpret that as "does not change observed performance".


Other than that I've got no objection to it.

Will be committed after adjusting the README.


Jan

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