[Pgpool-general] Problems configuring pgpool-II 3.0 to failover gracefully and load balance queries

[Guillaume Lelarge]

Le 21/02/2011 19:59, Stephen Sugden a écrit :
> Hello everybody,
> 
> I am trying to configure pgpool-II to load balance queries and provide
> failover for 2 (or more) identical backend servers. The application that
> will access pgpool only does SELECT queries. The back end servers are
> written to directly by a custom ETL process (e.g. no slony or pg9
> replication).
> 
> In my tests I have observed the following behaviour:
> 
> - Load Balancing appears to load balance incoming connections, not queries.
> If I open a single connection and execute a series of select queries, they
> all get routed to the same backend. If I open up multiple connections, both
> backends are used.

Which is what we call session pooling. I don't see an issue here.

> - When a node shuts down the pool drops *all* connections. (but subsequent
> connections are correctly only sent to the backend that is still up)
> - re-adding a node to the pool using pcp_attach_node causes the pool to
> reset and all current connections will be closed
> 
> Is this expected behaviour?

Not for the two last ones. Probably Tatsuo could explain that.


-- 
Guillaume
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