On Tue, 25 Sep 2007, Tatsuo Ishii wrote:

Now that PostgreSQL 8.3 enables autovacuum by default, I think pgbench
should stop issuing vacuum in pgbench -i since an ordinary vacuum will
take very long time under autovacuum running. If there's no objection,
I will remove vacuum from pgbench.

Just removing the vacuum might cause backwards test repeatability issues for some people, and fixing all the issues in this area will take a bigger change than you're suggesting. There are already the -n and -v parameters to adjust what gets vacuumed and what doesn't, and if you just read the documentation on those it's really confusing. I had to look at the source code to fully understand what they did.

I think you're right that something should be done to pgbench to address that a default auto-vacuum configuration is going to change how some people want to run the tool, but I don't think it's as simple as "remove vacuum from pgbench"; in order to have a smooth transition, I'd want to see the old behavior still available. If the default changes, that would require inverting the command line switches, and now you're talking about a much messier change.

Because of that, I personally wouldn't touch anything in the code at this late point in the 8.3 cycle. An update to the documentation to clarify how you might change the use of -n/-v based on whether autovaccum is turned on, and hopefully improving the description of both those switches in the process, would be a welcome improvement, and I could help out with that.

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

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TIP 9: In versions below 8.0, the planner will ignore your desire to
      choose an index scan if your joining column's datatypes do not

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