Re: Does PostgreSQL check database integrity at startup?

Em 26/12/2017 12:25, Pavel Stehule escreveu:
>
>
> 2017-12-26 14:44 GMT+01:00 Martin Marques
> <martin(dot)marques(at)2ndquadrant(dot)com <mailto:martin(dot)marques(at)2ndquadrant(dot)com>>:
>
> El 26/12/17 a las 09:52, Edson Carlos Ericksson Richter escribió:
> > Recently I had a problem with a base file with size 0 in a
> standby server.
> >
> > This raised one question: does PostgreSQL (9.6.6) check base
> integrity
> > at startup?
> >
> > At least if there are 0 byte size files in base dir? Or CRC?
> Something?
>
> Yes it has CRC check, but only if you initialize the cluster with
> --data-checksums, and there's a price to pay in performance.
>
>
> It has CRC check, but it is used in runtime - when data are necessary
>
> So Postgres usually check nothing on start - few system tables and indexes
>
> Regards
>
> Pavel
>
>
> --
> Martín Marqués http://www.2ndQuadrant.com/
> PostgreSQL Development, 24x7 Support, Training & Services
>
>

Any tips to make database server don't start if corrupt?
If I can change the startup script to make some checks before
effectively starting the database, what would be the recommendations?

One that seems obvious to me are empty data files (something like "find
-size 0 $PG_DATA/base")...
But I'm sure that more experienced PostgreSQL DBA would have more tests
to check before startup.

Thanks,

Edson