postgres-xc-general Mailing List for Postgres-XC

Hi,

yes, persistent_datanode_connections is now set to off - it may not be
related to the issues I have.

What amount of memory do you have on your datanodes & coordinator ?

Here are my settings :
datanode : shared_buffers = 512MB
coordinator=256MB (now, was 96MB)

I still get for some distributed tables (by hash)
"ERROR: Could not commit prepared transaction implicitely"

For distribution syntax, yes, I found your webpage talking about
regression tests

> You also have to know that it is important to set a limit of connections on
> datanodes equal to the sum of max connections on all coordinators.
> For example, if your cluster is using 2 coordinator with 20 max connections
> each, you may have a maximum of 40 connections to datanodes.

Ok, tweaking this today and launching the tests again...


Lionel F.



2011/5/31 Michael Paquier <mic...@gm...>:
>
>
> On Mon, May 30, 2011 at 7:34 PM, Lionel Frachon <lio...@gm...>
> wrote:
>>
>> Hi again,
>>
>> I turned off connection pooling on coordinator (dunno why it sayed
>> on), raised the shared_buffers of coordinator, allowed 1000
>> connections and the error disappeared.
>
> I am not really sure I get the meaning of this, but how did you turn off
> pooler on coordinator.
> Did you use the parameter persistent_connections?
> Connection pooling from coordinator is an automatic feature and you have to
> use it if you want to connect from a remote coordinator to backend XC nodes.
>
> You also have to know that it is important to set a limit of connections on
> datanodes equal to the sum of max connections on all coordinators.
> For example, if your cluster is using 2 coordinator with 20 max connections
> each, you may have a maximum of 40 connections to datanodes.
> This uses a lot of shared buffer on a node, but typically this maximum
> number of connections is never reached thanks to the connection pooling.
>
> Please node also that number of Coordinator <-> Coordinator connections may
> also increase if DDL are used from several coordinators.
>
>> However, all data is still going on one node (and whatever I could
>> choose as primary datanode), with 40 warehouses... any specific syntax
>> to load balance warehouses over nodes ?
>
> CREATE TABLE foo (column_key type, other_column int) DISTRIBUTE BY
> HASH(column_key);
> --
> Michael Paquier
> http://michael.otacoo.com
>