[Postgres-xl-developers] Postgres XL and Npgsql: Coordinator Exception
koichi.dbms at gmail.com
Wed Apr 8 19:55:32 PDT 2015
Was the configuration successful? You can check pgxc_node catalog to
see your cluster configuration. Also, you can raise the message
level to have more detailed info on the exception.
If you are checking that a datanode is running, you can issue select
statement directly to a datanode, which should work. Also, to check
connectivity from coordinator to datanode, you can use "EXECUTE
DIRECT" statement to issue read sql statement to a datanode.
2015-04-09 11:49 GMT+09:00 Jaaromy Zierse <jzierse at ghostery.com>:
> I updated the data node directly simply as a test, since inserting via the coordinator is throwing the exception. I simply wanted to verify that the issue wasn't something to do with a connection problem with the server or something similar.
>> On Apr 8, 2015, at 8:43 PM, Koichi Suzuki <koichi.dbms at gmail.com> wrote:
>> It is XL's specification that no direct updating operation is allowed
>> to maintain data integrity within the cluster. In other words,
>> datanode is a backend element and is normally invisible from
>> Could you let me know the background that you are updating datanode directly?
>> Koichi Suzuki
>> 2015-04-09 8:25 GMT+09:00 Jaaromy Zierse <jzierse at ghostery.com>:
>>> I am getting the following error when using Npgsql to execute any statement
>>> against any of my Postgres XL coordinators:
>>> ERROR: XX000: Could not begin transaction on data node.
>>> Connecting via pgAdmin III and executing a query against the coordinators
>>> successfully executes and distributes the data.
>>> Strangely, if I connect directly to the Datanodes using Npgsql, then the
>>> statements execute successfully.
>>> Here is an example of the Npgsql code:
>>> using (var connection = new NpgsqlConnection(connectionString))
>>> using (var command = connection.CreateCommand())
>>> command.CommandText = @"SET TRANSACTION READ WRITE;
>>> INSERT INTO test_table(
>>> id, name)
>>> VALUES (1, 'Rando');";
>>> Below is a description of our cluster configuration:
>>> Server: DEV-PGGTM
>>> Postgres XL Components: GTM and GTM Proxy
>>> Server: DEV-PG1
>>> Postgres XL Components: Coordinator 1 (Coord1) and Datanode1 (Datanode1)
>>> Server: DEV-PG2
>>> Postgres XL Components: Coordinator 2 (Coord2) and Datanode2 (Datanode2)
>>> Server: DEV-PG1
>>> Postgres XL Components: Coordinator 1 (Coord3) and Datanode3 (Datanode3)
>>> All coordinators run on port 5432 and all datanodes run on port 15432.
>>> The GTM is using port 6666 and the GTM Proxy is using port 6668.
>>> Thank you.
>>> BPM Camp - Free Virtual Workshop May 6th at 10am PDT/1PM EDT
>>> Develop your own process in accordance with the BPMN 2 standard
>>> Learn Process modeling best practices with Bonita BPM through live exercises
>>> http://www.bonitasoft.com/be-part-of-it/events/bpm-camp-virtual- event?utm_
>>> Postgres-xl-developers mailing list
>>> Postgres-xl-developers at lists.sourceforge.net
More information about the Postgres-xl-developers