[Pgpool-general] Replication Mode and Sequences

[Tatsuo Ishii]

> > > > pgpool-II won't do load balance when there are select and
> > > insert/update/delete statements in the same transaction. Instead, it
> > > will execute all queries against the master node and the
> > > insert/update/delete ones against the slave node only.
> > > 
> > > No. When a client connects to pgpool-II, pgpool-II will select
> > > randomly one of the nodes for load balance. If the client start a
> > > transaction, pgpool-II sends "BEGIN" to all nodes. and if the client
> > > sends some DML, it will sends to all nodes as well. If the client
> > > then
> > > sends "load-balance possible"(see the attached diagram) SELECT, it
> > > will be sent to the node which pgpool-II chooses at the connection
> > > time.
> > 
> > I had understood from the documentation that it would always be the master node. Thanks for the clarification, Tatsuo.
> 
> Oh then the docs is outdated or I am wrong. Let me check.

Sorry, I was wrong. If load_balance is true and replicate_select is
false and in a transaction block, "load-balance possible"(see the
attached diagram) SELECT will be sent to master only. Note that DMLs
are always sent to all nodes.
--
Tatsuo Ishii
SRA OSS, Inc. Japan