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

[Stephen Sugden]

Short follow up, I see the same thing with version 2.3

-Stephen

On Mon, Feb 21, 2011 at 2:45 PM, Stephen Sugden <stephen at aers.ca> wrote:

> Regarding session pooling, that makes sense, and is not a major issue. I
> think I misread the documentation as implying something different.
> Especially the stuff about being able to load balance inside a transaction.
>
> As for the other issues, I'm glad to hear that I'm not wrong to be
> confused. I think I'll try the 2.x series release that ships with centos
> this afternoon and see if it exhibits the same behaviour.
>
> -Stephen
>
>
> On Mon, Feb 21, 2011 at 2:21 PM, Guillaume Lelarge <guillaume at lelarge.info
> > wrote:
>
>> 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
>>  http://www.postgresql.fr
>>  http://dalibo.com
>>
>
>
>
> --
> *Stephen Sugden*, *Data Scientist*  |  A.E.R.S. & TERAPEAK
> 2307-4464 Markham Street, Victoria, BC, CANADA V8Z 7X8
> +1 250 483 3271 (FAX)
> www.terapeak.com | www.aers.ca | [image: facebook]<http://www.facebook.com/pages/Terapeak/21544372056>
>  | [image: twitter] <http://twitter.com/terapeak>
>



-- 
*Stephen Sugden*, *Data Scientist*  |  A.E.R.S. & TERAPEAK
2307-4464 Markham Street, Victoria, BC, CANADA V8Z 7X8
+1 250 483 3271 (FAX)
www.terapeak.com | www.aers.ca | [image:
facebook]<http://www.facebook.com/pages/Terapeak/21544372056>
 | [image: twitter] <http://twitter.com/terapeak>
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