Re: Does PostgreSQL check database integrity at startup?

2017-12-26 16:37 GMT+01:00 Edson Carlos Ericksson Richter <
richter(at)simkorp(dot)com(dot)br>:

> 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>
> :
>
>> 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.
>

I don't think so anybody does it. Reading 1TB database needs more then few
hours.

Regards

>
> Thanks,
>
> Edson
>