Re: select on 22 GB table causes "An I/O error occured while sending to the backend." exception

Scott Marlowe escribió:

> scenario 1:  There's a postmaster, it owns all the child processes.
> It gets killed.  The Postmaster gets restarted.  Since there isn't one
> running, it comes up.

Actually there's an additional step required at this point.  There isn't
a postmaster running, but a new one refuses to start, because the shmem
segment is in use.  In order for the second postmaster to start, the
sysadmin must remove the PID file by hand.

> starts new child processes.  Meanwhile, the old child processes that
> don't belong to it are busy writing to the data store.  Instant
> corruption.

In this scenario, it is both a kernel fault and sysadmin stupidity.  The
corruption that ensues is 100% deserved.

--
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support