Re: [Postgres-xc-general] createdb: database creation failed: ERROR: Failed to get pooled connections

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

I may be stepping someone's else answer... But here is some input.

On Fri, Jun 22, 2012 at 9:30 PM, Neil Mooney <nm...@xu...> wrote:

> Can anyone point out where I am going wrong here ?
>
> Here is a complete log of what i've done to setup , error at the end:
>
> Data/Coordinator machines:
> ==========================
>
> node1:
> ======
>
> rm -fr /opt/postgres/data*
>
> mkdir -p /opt/postgres/data_coordinator1
> mkdir -p /opt/postgres/data_datanode1
>
> chown postgres: /opt/postgres/data_*
>
> su - postgres
>
> initdb -D /opt/postgres/data_coordinator1 --nodename coordinator1
> initdb -D /opt/postgres/data_datanode1 --nodename datanode1
>
> #configure /opt/postgres/data_coordinator1/postgres.conf with GTM server
> #configure /opt/postgres/data_datanode1/postgres.conf with GTM server
>
>
> postgres -X -p 15432 -D /opt/postgres/data_datanode1 >>logfile 2>&1 &
> postgres -C -D /opt/postgres/data_coordinator1 >>logfile 2>&1 &
>
> node2:
> ======
>
> rm -fr /opt/postgres/data*
>
> mkdir -p /opt/postgres/data_coordinator2
> mkdir -p /opt/postgres/data_datanode2
>
> chown postgres: /opt/postgres/data_*
>
> su - postgres
>
> initdb -D /opt/postgres/data_coordinator2 --nodename coordinator2
> initdb -D /opt/postgres/data_datanode2 --nodename datanode2
>
> #configure /opt/postgres/data_coordinator2/postgres.conf with GTM server
> #configure /opt/postgres/data_datanode2/postgres.conf with GTM server
>
> postgres -X -p 15433 -D /opt/postgres/data_datanode2 >>logfile 2>&1 &
> postgres -C -D /opt/postgres/data_coordinator2 >>logfile 2>&1 &
>
> each coordinator node:
> ======================
>
> postgres -C -D /opt/postgres/data_coordinator1 >>logfile 2>&1 &
>
You already started your nodes at an earlier step, so this is not necessary.
An error would be returned telling that node is already started like
postgres.

> GTM machine:
> =============
>
> rm -fr /opt/postgres/data*
>
> mkdir -p /opt/postgres/data_gtm
>
> chown postgres: /opt/postgres/data*
>
> su - postgres
>
> initgtm -D /opt/postgres/data_gtm -Z gtm
> gtm -D /opt/postgres/data_gtm >logfile 2>&1 &
>
You should start GTM *before* starting your 2 Coordinators and your 2
Datanodes.
Postgres-XC nodes need to register on GTM at start-up or they cannot start.


>
> Registering Nodes: (all datanodes ??? has been done on both, output below)
> ==================
>
> psql -c "CREATE NODE datanode1 WITH (TYPE = 'datanode', PORT = 15432)"
> postgres
> psql -c "CREATE NODE datanode2 WITH (TYPE = 'datanode', PORT = 15433)"
> postgres
> psql -c "SELECT pgxc_pool_reload()" postgres
> select oid,node_name from pgxc_node;
>

Here you have to launch CREATE NODE and pgxc_pool_reload on *each
Coordinator*. When you start up a node this node knows only about itself,
so you need to register all the other Coordinators and Datanodes.
Registering other Coordinators on a Coordinator is mandatory or you won't
be able to synchronize DDL among Coordinators, this could result in a table
being created on a Coordinator and not another.

So, in your case, launch the following queries:
- On Coordinator 1:
CREATE NODE datanode1 WITH (TYPE = 'datanode', PORT = 15432, HOST =
'$node1_ip');
CREATE NODE datanode2 WITH (TYPE = 'datanode', PORT = 15433, HOST =
'$node2_ip');
CREATE NODE coordinator2 WITH (TYPE = 'coordinator', PORT = 5432, HOST =
'$node2_ip');
- On Coordinator 2:
CREATE NODE datanode1 WITH (TYPE = 'datanode', PORT = 15432, HOST =
'$node1_ip');
CREATE NODE datanode2 WITH (TYPE = 'datanode', PORT = 15433, HOST =
'$node2_ip');
CREATE NODE coordinator1 WITH (TYPE = 'coordinator', PORT = 5432, HOST =
'$node2_ip');

In the case of node1, datanode1 and coordinator1 are on the same node. So
you can replace $node1_ip with localhost or 127.0.0.1 when defining
datanode1 for coordinator1.
Same for node node2, datanode2 and coordinator2 are on the same node. So
you can replace $node2_ip with localhost or 127.0.0.1 when defining
datanode2 for coordinator2.



> #output
>
> node1:
> postgres=# select oid,node_name from pgxc_node;
>  oid  |  node_name
> -------+--------------
>  11129 | coordinator1
>  16384 | datanode1
>  16385 | datanode2
> (3 rows)
>
This output is incorrect.
Coordinator 1 is not aware of Coordinator 2. Coordinator 1 also thinks that
datanode2 is on node1 as you did not define an IP to redirect correctly.


>
>
> node2:
> [postgres@las1-app015 ~]$ psql -c "select oid,node_name from pgxc_node;"
> postgres
>  oid  |  node_name
> -------+--------------
>  11129 | coordinator2
>  16384 | datanode1
>  16385 | datanode2
> (3 rows)
>
Same here, Coordinator 1 is not aware of Coordinator2.
Coordinator2 thinks that datanode1 is on the same server, which is not the
case as it looks that coordinator2/datanode2 and coordinator1/datanode1 are
grouped on 2 different nodes.

>
> Creating DB's :
> ===============
>
> [postgres@las1-app014 ~]$ createdb test
> createdb: database creation failed: ERROR:  Failed to get pooled
> connections
>

Here I guess you are connecting to coordinator1.
This error happens because coordinator1 cannot connect to datanode2, as it
is not located on local server but on server node2.

Regards,
-- 
Michael Paquier
http://michael.otacoo.com