Re: Does PostgreSQL check database integrity at startup?

2017-12-26 16:50 GMT+01:00 Edson Carlos Ericksson Richter <
richter(at)simkorp(dot)com(dot)br>:

> Em 26/12/2017 13:40, Pavel Stehule escreveu:
>
>
>
> 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
>>
>
> I'm rebuilding the standby server for two days already, with 23% of
> completion status...
> If lost the database and backups because of that failure, it would be a
> giant disaster.
> Few hours checking integrity would be acceptable... Specially if I can run
> it on standby only.
>

very simple check

pgdumpall > /dev/null

but this doesn't check indexes.

Regards

Pavel

> Regards,
>
> Edson
>