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Thread: delaying autovacuum freeze via storage params?

delaying autovacuum freeze via storage params?

From
Steve Kehlet
Date:
Hello, I'd like to postpone an "autovacuum: VACUUM public.mytable (to prevent wraparound)" and handle it manually at another time. I thought I could set these storage parameters on the large table in question ("mytable") like this:

ALTER TABLE mytable SET (
  autovacuum_freeze_min_age=10000000,
  autovacuum_freeze_table_age=800000000,
  autovacuum_freeze_max_age=1000000000
);

then kill the running autovacuum process, but unfortunately it just keeps coming back:

 mydb   | 22734 | 05/26/2015 23:29:10 | autovacuum: VACUUM public.mytable (to prevent wraparound)                                                                                                                   
I also tried setting the toast.autovacuum* storage parameters, as well as a postgres reload, but neither made any difference.

Here is the table's age:

mydb=> select age(relfrozenxid) from pg_class where oid = 'mytable'::regclass;
    age    
-----------
 203065951
(1 row)

So 203 million, which is just past the 200 million default (which is why I started looking at this). But it's less than the 1 billion I set the storage param to.

Here is \d+:

mydb=> \d+ mytable
                                              Table "public.mytable"
         Column          |            Type             |       Modifiers       | Storage  | Stats target | Description 
-------------------------+-----------------------------+-----------------------+----------+--------------+-------------
 (removed al lthis)
Options: autovacuum_freeze_min_age=10000000, autovacuum_freeze_table_age=800000000, autovacuum_freeze_max_age=1000000000, toast.autovacuum_enabled=false, toast.autovacuum_freeze_min_age=10000000, toast.autovacuum_freeze_table_age=800000000, toast.autovacuum_freeze_max_age=1000000000


I'm guessing I'm missing something here, can anyone offer suggestions or ideas on what I should try next?

Here is my version:

mydb=> SELECT version();
                                                    version                                                    
---------------------------------------------------------------------------------------------------------------
 PostgreSQL 9.3.4 on x86_64-unknown-linux-gnu, compiled by gcc (GCC) 4.1.2 20080704 (Red Hat 4.1.2-44), 64-bit
(1 row)

and I put my [custom settings in a gist](https://gist.github.com/skehlet/bcdbc1ce1f212d3b7bb2).

Thanks!

Re: delaying autovacuum freeze via storage params?

From
Alvaro Herrera
Date:
Steve Kehlet wrote:
> Hello, I'd like to postpone an "autovacuum: VACUUM public.mytable (to
> prevent wraparound)" and handle it manually at another time. I thought I
> could set these storage parameters on the large table in question
> ("mytable") like this:
>
> ALTER TABLE mytable SET (
>   autovacuum_freeze_min_age=10000000,
>   autovacuum_freeze_table_age=800000000,
>   autovacuum_freeze_max_age=1000000000
> );

See the docs about the freeze max age storage parameter -- the per-table
setting can decrease the global setting but not increase it.  You can
increase the global setting (postgresql.conf) to 2 billion AFAIR which
should give you plenty of room.  Needs a server restart though.

--
Álvaro Herrera                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Re: delaying autovacuum freeze via storage params?

From
Steve Kehlet
Date:
On Tue, May 26, 2015 at 7:27 PM Alvaro Herrera <alvherre@2ndquadrant.com> wrote:
See the docs about the freeze max age storage parameter -- the per-table
setting can decrease the global setting but not increase it. 

Thanks Alvaro, that explains it. I found it in the docs: "Note that autovacuum will ignore attempts to set a per-tableautovacuum_freeze_max_age larger than the system-wide setting (it can only be set smaller)."