Обсуждение: 8.3 Autovacuum Questions
I just have a couple of quick questions about 8.3 and Autovacuum.
1. When autovacuum chooses to vacuum a table, the entire table is vacuumed, and not just a specified percentage of the table. Correct?
2. There is no way, without turning autovacuum off, of excluding vacuum/analyze during a specific period of time (say during a known peak usage period).
3. If I have a PostgreSQL cluster with 10 databases, does autovacuum_max_workers=3 mean I have a possibility of 3 total workers or 30 workers (i.e. autovacuum_max_workers * number of db's)?
Thanks,
Chris
1. When autovacuum chooses to vacuum a table, the entire table is vacuumed, and not just a specified percentage of the table. Correct?
2. There is no way, without turning autovacuum off, of excluding vacuum/analyze during a specific period of time (say during a known peak usage period).
3. If I have a PostgreSQL cluster with 10 databases, does autovacuum_max_workers=3 mean I have a possibility of 3 total workers or 30 workers (i.e. autovacuum_max_workers * number of db's)?
Thanks,
Chris
Chris Hoover escribió: > I just have a couple of quick questions about 8.3 and Autovacuum. > > 1. When autovacuum chooses to vacuum a table, the entire table is vacuumed, > and not just a specified percentage of the table. Correct? Yes. > 2. There is no way, without turning autovacuum off, of excluding > vacuum/analyze during a specific period of time (say during a known peak > usage period). Nope, no way. (You could have a script to update the pg_autovacuum.enabled flag, and change it using cron.) > 3. If I have a PostgreSQL cluster with 10 databases, does > autovacuum_max_workers=3 mean I have a possibility of 3 total workers or 30 > workers (i.e. autovacuum_max_workers * number of db's)? 3 workers total. -- Alvaro Herrera http://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc.
On Mon, Jul 14, 2008 at 4:29 PM, Alvaro Herrera <alvherre@commandprompt.com> wrote:
Chris Hoover escribió:> I just have a couple of quick questions about 8.3 and Autovacuum.Yes.
>
> 1. When autovacuum chooses to vacuum a table, the entire table is vacuumed,
> and not just a specified percentage of the table. Correct?Nope, no way. (You could have a script to update the
> 2. There is no way, without turning autovacuum off, of excluding
> vacuum/analyze during a specific period of time (say during a known peak
> usage period).
pg_autovacuum.enabled flag, and change it using cron.)3 workers total.
> 3. If I have a PostgreSQL cluster with 10 databases, does
> autovacuum_max_workers=3 mean I have a possibility of 3 total workers or 30
> workers (i.e. autovacuum_max_workers * number of db's)?
--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.
Alvaro,
Thanks a bunch for the concise answers. That is exactly what we needed to confirm.
Chris