Re: Autovacuum Transaction Wraparound

On 3/11/19 1:24 PM, Perumal Raj wrote:
> Hi Adrian
>
> What was the full message?
>
>            autovacuum: VACUUM <table name >(to prevent wraparound)
>
> Though i am running vacuum manually (nowadays) and autovacuum is running
> perfectly once its threshold reaches.
>
> What will happen if my DB reaches 200M transaction age again ? ( Here my
> understanding is no dead tuples to cleanup --- I may be missing full
> concept , Please correct me if i am wrong) .
>
> What will be impact to DB ( Performance ) During Vacuum freeze ( My
> Assumption is autovacuum will run "vacuum freeze" once DB age reached
> 200M ) ?

I would read this:

https://www.postgresql.org/docs/9.2/routine-vacuuming.html#VACUUM-FOR-WRAPAROUND

I believe it will answer most of your questions.

>
> When should i consider to increase pg_settings value with respect to
> Autovacuum ?
>
> Regards,
>
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com