Re: error updating a tuple after promoting a standby

Perhaps try 9.5.5 which has a fix for a problem with the same symptoms:

https://wiki.postgresql.org/wiki/Free_Space_Map_Problems
https://www.postgresql.org/docs/9.5/static/release-9-5-5.html#AEN126074

On Wed, Dec 21, 2016 at 10:51:47AM +0100, Tom DalPozzo wrote:
> Hi,
> I was doing some tests with backup, replication, standby. After promoting a
> standby server, I found my db in a condition that raises me an error while
> trying to update a particular tuple.
> Below here you can se my UPDATE statment and the error raised.
> The select * from stato where id=409; executed immediately after worked
> well however.
> I checked the file and it's readable.
> Before my standby promotion test I performed millions of this UPDATE
> statments without problem on my db.
> I can not reproduce the issue.
>
> Perhaps I did something wrong during my test but I don't know what. I
> didn't touch any file in base directory however.
> Anyway I'd like to know if in your opinion it's possible that this error
> was caused by something wrong done by me or if it should never happen as
> the file is perfectly readable.
>
> Regards
> Pupillo
>
>
>
>
> psql (9.5.4)
> Type "help" for help.
>
> ginopino=# UPDATE stato SET
> dati='\x5353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353535353'
> WHERE id=409;
> ERROR: could not read block 12281 in file "base/16384/29153": read only 0
> of 8192 bytes
> ginopino=# select * from stato where id=409; <<< IT WORKS FINE

--
Brian Sutherland