On Sun, 11 Feb 2007, Tom Lane wrote:

Does this have any impact on the reported results (by slowing pg_bench

I didn't put more code than I had to in the transaction path, to avoid any slowdown. I didn't convert the timestamp to human readable format or anything intensive like that to avoid impacting the pgbench results. It's just dumping some data that was already sitting there.

There is an extra if statement for each transaction, and a slightly longer fprintf when running with the extra latency output in place. That's it. The file gets "%d %d %.0f %d %ld %ld\n" instead of "%d %d %.0f\n"

The main drawback to logging more as the default is about twice as much disk I/O for writing the latency log out. That's small change compared with the WAL/database writes that must be going on to generate that transaction, and I sure haven't been able to measure any change in results.

* Greg Smith [EMAIL PROTECTED] http://www.gregsmith.com Baltimore, MD

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