Re: [Postgresql 8.2.3] autovacuum starting up even after disabling ?

---------- Forwarded Message ----------

Subject: Re: [GENERAL] [Postgresql 8.2.3] autovacuum starting up even after
disabling ?
Date: Friday 04 July 2008 9:51 am
From: dushy <dushyanth(at)gmail(dot)com>
To: "Adrian Klaver" <aklaver(at)comcast(dot)net>

Hey,

Thanks for the quick reply.

> From the docs:
> http://www.postgresql.org/docs/8.3/interactive/runtime-config-autovacuum.ht
>ml
>
> autovacuum (boolean)
>
> Controls whether the server should run the autovacuum launcher daemon.
> This is on by default;

http://www.postgresql.org/docs/8.2/interactive/runtime-config-autovacuum.html

Docs for 8.2 say its off by default. I did check the above link :),
missed mentioning it here though.

> --> Note that even when this parameter is disabled, the system will
> launch autovacuum processes if necessary to prevent transaction ID
> wraparound. See Section 23.1.3 for more information.

Quoting that section : The maximum time that a table can go unvacuumed
is two billion transactions minus the vacuum_freeze_min_age that was
used when it was last vacuumed. If it were to go unvacuumed for longer
than that, data loss could result. To ensure that this does not
happen, the autovacuum facility described in Section 22.1.4 is invoked
on any table that might contain XIDs older than the age specified by
the configuration parameter autovacuum_freeze_max_age. (This will
happen even if autovacuum is otherwise disabled.)

db=# show vacuum_freeze_min_age;
vacuum_freeze_min_age
-----------------------
100000000
(1 row)

db=# show autovacuum_freeze_max_age;
autovacuum_freeze_max_age
---------------------------
200000000
(1 row)

None of the tables seem to have hit that limit. I executed the below
query to check the age and they are all < 200 million.

Below are the unique age(relfrozenxid) for my tables.

161206586
161273308
193226476
76684520

Thanks
Dushyanth

Am forwarding back to list.
One question? Did you do pg_ctl reload after changing the config file?

--
Adrian Klaver
aklaver(at)comcast(dot)net