Re: [Postgres-xc-general] coordinator deaths

[Michael P. <mic...@gm...>]

On Wed, Sep 19, 2012 at 10:12 AM, Shavais Zarathustra <sh...@gm...>wrote:

> Hello,
>
> I've been using a computer on which gmail was already logged in.  I
> mistakenly assumed it was logged into my account.  Sorry about that.
>
Don't worry :)

>
> The pgxc_node_name setting was set to 'coord1' and 'datanode1' in
> data_coord1/postgresql.conf and data_datanode1/postgersql.conf,
> respectively.
>
OK, nice.

>
> I reinitialized the install, as you suggested (except I just shut
> everything down, blew away the data_* folders in /usr/local/pgsql, and
> reused those instead of using $HOME/pgsql/data_*), and, so far, that seems
> to have fixed the problem.  (I guess probably those data_* folders should
> be under /var somewhere..)
>
> I'm not sure what the problem was.  I think I recall having attempted to
> issue a sql command to create a coordinator node, the previous time around.
>  I notice your steps don't include that step?  I wonder if somehow that
> affected things?
>
When you initialized a node with initdb, --nodename is a mandatory option.
This option value is used to set up pgxc_node_name automatically and
initialize the catalog pgxc_node with the data of the node itself.
You need to create a Coordinator with CREATE NODE on a Coordinator only if
there is at least 2 Coordinators in your cluster.


> The reason I had set the port in datanode1's postgresql.conf was because I
> would like to use gtm_ctl and pg_ctl to start up and shutdown, using an
> init.d script, (ala service postgresql-xc start / restart / stop) and I
> haven't been able to get pg_ctl to pass the port parameter to postgres.
> (pg_ctl ... -o -p 15432 doesn't work; apparently I'm misinterpreting the
> usage docs).  After putting that setting back in again, I'm using gtm_ctl
> and pg_ctl to start and stop it all at this point, and it seems to working
> fine.
>
Nice to hear that it is working. I am sure you missed something at
initialization.
When you want to add a port number with pg_ctl, be sure to use quotes with
-o, like:
-o "-p $PORT"

The XC documentation is not perfect, if you could point to the page and the
paragraph where you had doubts I can try to have a look and correct the doc
if necessary.


> The pgbench utility wasn't installed, but I finally found it and installed
> it.  I notice that it somehow left a bunch of idle connection processes
> behind after exiting.  Would those get reused, or is that a problem with
> pgbench?  (I restarted postgres-xc and they went away, but.  Just
> wondering.)
>
The connection pooling of XC is made to maintain connections between nodes
as it consumes a bunch of ressources to create connections on the fly for
each transaction.
You can however drop those connections with CLEAN CONNECTION, command
specific to XC:
http://postgres-xc.sourceforge.net/docs/1_0/sql-cleanconnection.html
-- 
Michael Paquier
http://michael.otacoo.com