Re: psql or pgbouncer bug?

On 05/21/2010 11:19 AM, Jakub Ouhrabka wrote:
> Hi,
>
> can anyone tell me how this could happen, please?
>
> database=# begin; update table set col = 100;
> server closed the connection unexpectedly
> This probably means the server terminated abnormally
> before or while processing the request.
> The connection to the server was lost. Attempting reset: Succeeded.
> UPDATE 153
> database=# ROLLBACK ;
> WARNING: there is no transaction in progress
> ROLLBACK
>
> The update was commited to database. This was psql 8.4 connectig to 8.2
> server through pgbouncer 1.3.
>
> It's not reproducible for me :-(
>
> Any ideas?

1. you connect to pgbouncer using psql
2: you execute the query and something (firewall whatever) drops the
connection between psql and pgbouncer while the one between pgbouncer
and the backend stays alive
3. psql notices the lost connection and reconnects and you end up on
another backend session (or the same one that was just RESET ALL; by
pgbouncer after the UPDATE completed)
4. the ROLLBACK; does nothing because the pooled connection you are now
connected is either a different one or got reset after the connection
dropped.

Stefan