[HACKERS] Turn off vacuum in pgbench?
Hi, 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. -- Tatsuo Ishii SRA OSS, Inc. Japan ---(end of broadcast)--- TIP 7: You can help support the PostgreSQL project by donating at http://www.postgresql.org/about/donate
Re: [HACKERS] Turn off vacuum in pgbench?
Tatsuo Ishii <[EMAIL PROTECTED]> writes: > 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. I'd be inclined to leave it there, simply because you'll be changing the conditions of the benchmark if you take it out. I have not noticed any particular problems with it... regards, tom lane ---(end of broadcast)--- TIP 7: You can help support the PostgreSQL project by donating at http://www.postgresql.org/about/donate
Re: [HACKERS] Turn off vacuum in pgbench?
On 9/25/07, Tom Lane <[EMAIL PROTECTED]> wrote: > > > > I'd be inclined to leave it there, simply because you'll be changing > the conditions of the benchmark if you take it out. I have not noticed > any particular problems with it... The only problem I faced is while executing custom scripts using pgbench. You either need to do the initialization (pgbench -i) or run with -n option (no vacuum). But I don't have any strong preference here. Thanks, Pavan -- Pavan Deolasee EnterpriseDB http://www.enterprisedb.com
Re: [HACKERS] Turn off vacuum in pgbench?
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 ---(end of broadcast)--- 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 match
Re: [HACKERS] Turn off vacuum in pgbench?
On Tue, 2007-09-25 at 22:16 +0530, Pavan Deolasee wrote: > The only problem I faced is while executing custom scripts using > pgbench. > You either need to do the initialization (pgbench -i) or run with -n > option > (no vacuum). But I don't have any strong preference here. Yes, I had that problem too. pgbench allows you to run a script file, but there is no way to run an initialiser script for a custom workload. Worse, if you don't do -n when you run a custom script, it tells you that the branches table doesn't exist, which is strange if you aren't using that in your scripts. Proposed enhancement to pgbench: -g filename runs filename prior to start of main test transactions. Only used in conjunction with the -f option. Normal cleaning/vacuuming of TPC-B tables does not occur if -g option set. -- Simon Riggs 2ndQuadrant http://www.2ndQuadrant.com ---(end of broadcast)--- TIP 2: Don't 'kill -9' the postmaster
Re: [HACKERS] Turn off vacuum in pgbench?
Tom Lane wrote: > Tatsuo Ishii <[EMAIL PROTECTED]> writes: > > 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. > > I'd be inclined to leave it there, simply because you'll be changing > the conditions of the benchmark if you take it out. I have not noticed > any particular problems with it... I wonder if autovacuum itself is going to add more variability to the test (like we don't have enough already). -- Bruce Momjian <[EMAIL PROTECTED]>http://momjian.us EnterpriseDB http://postgres.enterprisedb.com + If your life is a hard drive, Christ can be your backup. + ---(end of broadcast)--- TIP 6: explain analyze is your friend
Re: [HACKERS] Turn off vacuum in pgbench?
Bruce Momjian <[EMAIL PROTECTED]> writes: > Tom Lane wrote: >> I'd be inclined to leave it there, simply because you'll be changing >> the conditions of the benchmark if you take it out. I have not noticed >> any particular problems with it... > I wonder if autovacuum itself is going to add more variability to the > test (like we don't have enough already). Of course it will, which means that people will likely turn off autovac when trying to obtain repeatable pgbench numbers, which is another reason not to take out the built-in vacuum step. regards, tom lane ---(end of broadcast)--- TIP 2: Don't 'kill -9' the postmaster
