Re: Vacuum Full - Mailing list pgsql-admin
| From | Rafael Domiciano |
|---|---|
| Subject | Re: Vacuum Full |
| Date | |
| Msg-id | 3a0028490904011451t4efea40m604aeb4c1574becd@mail.gmail.com Whole thread Raw |
| In response to | Re: Vacuum Full (Scott Marlowe <scott.marlowe@gmail.com>) |
| Responses |
Re: Vacuum Full
|
| List | pgsql-admin |
On Tue, Mar 31, 2009 at 1:20 PM, Scott Marlowe <scott.marlowe@gmail.com> wrote:
So, why Vacuum Full should not nomally be needed? Vacuum Analyze is enough for Maintenance Base?
One more question, If I understood Vacuum Full it's similar to Defrag Tool like Defrag Windows. So, like defraging Windows, it's speed up a little (the disc is going to read the blocks faster) , Vacuuming Full Postgres should have the same behavior?!
The fsm_pages values incresead from 120000 to 320000, and now is around that every day.
On more question, the postgres.conf max_fsm_pages is set to 150000, and every vacuum hint me to increase this parameter. Does it have any impact in the normal operation of Postgres?
No, I'm not running autovacuum in the 8.1, but in the 8.3 I'm going to autovacuum by default.On Tue, Mar 31, 2009 at 10:04 AM, Rafael DomicianoGenerally speaking, vacuum full should not normally be needed.
<rafael.domiciano@gmail.com> wrote:
> Hello People,
>
> I have some doubts about Vacuum Full. There We go:
> 1) The Only thing that Vacuum Full (Only Full, not Analyze) is to clean
> "dead space" on the disc, and reorganize the relation at the physical level?
> If it's true, so doing this may speed up select's, while the Postgres will
> going to do less hit in the disc. I'm right?
Regular vacuuming should free up enough free space that the table
reaches an equilibrium where it has some small percentage of available
space (5 to 15% or so) and stay there.
So, why Vacuum Full should not nomally be needed? Vacuum Analyze is enough for Maintenance Base?
One more question, If I understood Vacuum Full it's similar to Defrag Tool like Defrag Windows. So, like defraging Windows, it's speed up a little (the disc is going to read the blocks faster) , Vacuuming Full Postgres should have the same behavior?!
If the needed fsm settings need to keep increasing then something is wrong.
> 2) Doing only Vacuum Analyze I have a enlargement of the parameter
> max_fsm_pages. Does it have any impact in the operation?
> Should I increment the value in the conf to be so large than the Vacuum
> Verbose shows me?
The fsm_pages values incresead from 120000 to 320000, and now is around that every day.
On more question, the postgres.conf max_fsm_pages is set to 150000, and every vacuum hint me to increase this parameter. Does it have any impact in the normal operation of Postgres?
Yeah, 8.3 is faster.
> 3) There are differences in performace of Vacuum Full between versions 8.1.4
> and 8.3.7?
> As soon as possible we are going to migrate the Postgres to 8.3.7, just
> waiting the finish of the tests of the software in the new version.yep, vacuum full, then reindex.
> 4) The right way to run Vacuum and Reindex is: Vacuum and Reindex or Reindex
> and Vacuum?
> Running Vacuum I have a Index Bloat, right?! So I have to run Reindex afet
> Vacuum?!
> If true I'll change the script to make first Vacuum and then Reindex.Not that I know of.
> 5) Does have any way to see how much is left to finish vacuum?
I notice you don't mention autovacuum. Are you running it? And if
not, why not?
Thnks for Response
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