Re: pgpool II, streaming replication and HA

On 01/27/2016 11:53, Tatsuo Ishii wrote:

> There's a file called "pool_status" which records the previous status
> of the DB servers. So the file records that "A is down, B is up". In
> your case, when A reboots, the old primary server on A may start as a
> primary, but from the file pgpool knows that the PostgreSQL on A was
> down and never automatically regards it online. So any query sent to
> pgpool will be routed to the new primary running on B, never routed to
> A.
>
> To make the old primary on A usable, you need to shutdown the
> PostgreSQL (if it's running) and turn it to a new standby connecting
> to the current primary on B. You can do it by either "online recovery"
> feature of pgpool or do it manually using pg_basebackup etc. In the
> latter case, you need to "attach" 'the new standby to make it online
> by using pcp_attach_node.

Thank you for clarification.


--
Best regards,
Alexander Pyhalov,
system administrator of Southern Federal University IT department