From: Ron <ronljohnsonjr@gmail.com>
To: pgsql-admin@lists.postgresql.org
Subject: Re: Avoid Wraparound Failures
Date: Fri, 25 Mar 2022 23:45:31 -0500
Message-ID: <e94006fe-b953-720e-c6b8-a7f76145fa55@gmail.com> (raw)
In-Reply-To: <965a52fe849ec6e5759d349b4063b5077353f24b.camel@cybertec.at>
References: <CA+FWGK6HmRx8=-2wZkw-9a6a36f6iEGgAH=bN1rNicbFgzas5A@mail.gmail.com>
<965a52fe849ec6e5759d349b4063b5077353f24b.camel@cybertec.at>
On 3/25/22 23:34, Laurenz Albe wrote:
> On Fri, 2022-03-25 at 23:16 +0100, Loles wrote:
>> Suppose the databases on my instance are near to have a wraparound failure.
>>
>> (I think so, from what I see, but in the PostgreSQL log I haven't seen any warning about It yet).
>>
>> What do I have to do?
>>
>> vacuum freeze;
>>
>> better than,
>>
>> vacuum analyze;
>>
>> Or both?
>>
>> If the autovacuum_freeze configuration parameters have defaults values, should I modify any first?
>>
>> More I read of this topic, more confused I am.
>>
>> Please, I need simple and wise advice :)
> DON'T PANIC
>
> If what you see is the age of your oldest unfrozen rows approaching 200 million,
> everything is just normal. That's when anti-wraparound autovacuum *begins*.
>
> Normally, you have nothing to do, except perhaps make sure than autovacuum is
> fast enough (autovacuum_vacuum_cost_delay = 2).
>
> If you want to prevent that autovacuum run from happening while your system is
> busy (which normally also is no problem), you can trigger a manual VACUUM at
> a time of lower database activity. But make it a plain VACUUM, not a
> VACUUM (FREEZE)
Why not VACUUM FREEZE?
> or (god forbid) VACUUM (FULL), and only VACUUM those tables
> that are large and approaching the threshold. And don't VACUUM them all at the
> same time.
>
> Yours,
> Laurenz Albe
--
Angular momentum makes the world go 'round.
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To: pgsql-admin@postgresql.org
Cc: ronljohnsonjr@gmail.com, pgsql-admin@lists.postgresql.org
Subject: Re: Avoid Wraparound Failures
In-Reply-To: <e94006fe-b953-720e-c6b8-a7f76145fa55@gmail.com>
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