Re: How to send queries to master and failover to slave ?

Hello,

 

We have the very same scenario as Benoit describes – if the master instance fails, we would like the driver to communicate with the secondary instance for read-only operations before the failover process is commenced. The second use-case is when the master instance is deliberately shut down for maintenance reasons  and we do not want to fail over to the secondary instance, but instead allow it to process user queries throughout the maintenance.

 

For this, we intend to implement "preferMaster" targetServerType in the JDBC driver paramater. Would you consider it a good idea to integrate this feature into the official JDBC driver?

 

Cheers

 

Martin

 

From: pgsql-jdbc-owner@postgresql.org [mailto:pgsql-jdbc-owner@postgresql.org] On Behalf Of Benoit Salotti
Sent: Tuesday, June 28, 2016 11:41 AM
To: pgsql-jdbc@postgresql.org
Subject: How to send queries to master and failover to slave ?

 

Hi all,

 

I have a setup with 1 master and 1 slave (hot standy to serve read queries if necessary).

I would like the JDBC driver to talk preferrably to the master (to be sure to get the freshest data). If the master is not available I would like to send the queries to the slave.

 

The documentation mentions the following values for the parameter targetServerType: any, master, slave, preferSlave.

I'm surprised there is no preferMaster option which would allow me to implement easily my requirement.

 

Anyone already encountered the same need ?

 

Regards,

 

Benoit