Re: pg_upgrade - link mode and transaction-wraparound data loss

jesper@krogh.cc wrote:
> > on the old and new servers, but if you can only provide these values on
> > one of the two servers, it is still useful.  Thanks.
> 
> Hi Bruce, thanks for your prompt response.
> 
> First the new one..

Great.

> jk@pal:~$ psql -p 5433
> psql (9.0beta1)
> Type "help" for help.
> 
> data=# SELECT datname, datfrozenxid FROM pg_database;
>   datname  | datfrozenxid
> -----------+--------------
>  template0 |          654
>  postgres  |   2374592801
>  data      |   2023782337
>  jk        |   2023822188
>  template1 |   2374592801
>  workqueue |   2023822188
> (6 rows)
> 
> data=#         SELECT txid_current();
>  txid_current
> --------------
>    2375384556
> (1 row)
> 
> data=# \q
> 
> Then the old one.
> 
> jk@pal:~$ psql data
> psql (9.0beta1, server 8.4.1)
> WARNING: psql version 9.0, server version 8.4.
>          Some psql features might not work.
> Type "help" for help.
> 
> data# SELECT datname, datfrozenxid FROM pg_database;
>   datname  | datfrozenxid
> -----------+--------------
>  template0 |   2073823552

This line above looks very odd because I didn't think the template0
datfrozenxid could be advanced.  Can I see the output of this query:
SELECT datname, datfrozenxid, datallowconn FROM pg_database;

I am wondering if you set datallowconn for template0 to 'true'.

>  postgres  |   2023820521
>  data      |   2023782337
>  jk        |   2023822188
>  template1 |   2073823552
>  workqueue |   2023822188
> (6 rows)
> 
> data=# SELECT txid_current();
>  txid_current
> --------------
>    2390524243
> (1 row)
> 
> 
> The old database has been "copied" over using rsync and
> pg_start_backup()/pg_stop_backup() procecures and started up
> using a recovery.conf file.

My other idea is that somehow recovery touches datallowconn for
template0.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com