Re: vacuum_freeze_table_age for 9.3.2

On 12/5/2013 11:29 AM, Giuseppe Broccolo wrote:
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> Il 05/12/2013 17:16, Andy Colson ha scritto:
>> The docs say vacuum, but the param is vacuum_freeze_table_age, so
>> do I need to "vacuum freeze" all the tables, or is vacuum enough?
>>
>> Also, will "set vacuum_freeze_table_age = 0; vacuum freeze;" work,
>> or do I need to modify the postgresql.conf and reload?
>
> Setting vacuum_freeze_table_age to 0 forces VACUUM to always scan all
> pages, effectively ignoring the visibility map. In this way a scan of
> the whole table is done, ensuring all old XIDs are replaced by FrozenXID.
>
> vacuum_freeze_table_age is a parameter with context 'user', meaning
> that you can set it during a session and run a "vacuum freeze" with
> the modified setting.
>
> Giuseppe.

I gather, then, that vacuum alone is enough. It'll scan the entire
table and if it finds something wonky it'll freeze it. A "vacuum
freeze" would be over kill and might freeze a bunch of stuff that isnt
broken. (It wouldn't hurt to freeze it, but I have enough IO at the
moment and just wanna fix whats broken).

For now I'm only doing vacuum's, so hopefully that's enough.

Thanks for the help.

-Andy