Re: [Postgres-xc-general] DROP NODE

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Could you let me know what release you used.   I suppose 1.2.1 and 1.1.1 has this fix.   Also let me know how you dropped node, manually or by pgxc_ctl?
---
Koichi Suzuki

2014/04/09 1:46、Sergio Sinuco <ser...@da...<mailto:ser...@da...>> のメール：

Hi. I decided to modify my configuration like this:

Node A: 1 gtm master
Node B: 1 gtm_proxy,
1 coordinator master, 1 coordinator slave (for node C coordinator),
1 datanode master, 1 datanode slave (for node C data node)
Node C: 1 gtm_proxy,
1 coordinator master, 1 coordinator slave (for node B coordinator),
1 datanode master, 1 datanode slave (for node B data node)
Node D: 1 gtm slave

I added following lines in postgresql.conf of each data node slave. pgxc_ctl script didn't add them.

archive_mode = off
archive_command = ''
max_wal_senders = 0
wal_level = minimal

In normal operation, everything worked fine.

Fist I killed data node master in Node B, I promoted corresponding data node slave to master with pgxc_ctl. I got the following error:

ERROR:  PGXC node datanode1: two nodes cannot be primary
 pgxc_pool_reload
------------------
 t
(1 row)

ERROR:  PGXC node datanode1: two nodes cannot be primary
 pgxc_pool_reload
------------------
 t
(1 row)

In both master coordinators, I queried pgxc_node and the failed datanode still pointed to node B. I had to execute ALTER NODE for change host and primary property. After that, everything worked fine.

Then, I killed coordinator master in Node B, I promoted corresponding coordinator slave to master. I got the following results:

ALTER NODE
 pgxc_pool_reload
------------------
 t
(1 row)

ERROR:  Failed to get pooled connections
CONTEXT:  SQL statement "EXECUTE DIRECT ON (coord1) 'SELECT pg_catalog.pg_try_advisory_xact_lock_shared(65535, 0)'"
 pgxc_pool_reload
------------------
 t
(1 row)

So in new master coordinator, when I queried pgxc_node the failed coordinator pointed correctly to node C. But in the original master coordinator of node C, when I queried pgxc_node the failed coordinator pointed to node B. In this coordinator I tried to modify failed coordinator with ALTER NODE but I got the same error Failed to get pooled connections.

Finally when I execute ALTER TALBE … DELETE NODE for a table, in the new master coordinator it executed ok. But in the original master coordinator of node C I got the same error Failed to get pooled connections.

Is this behaviour normal? What can i do?

2014-04-02 23:19 GMT-05:00 鈴木 幸市 <ko...@in...<mailto:ko...@in...>>:
Before removing a datanode, you should drop the datanode from tables before you drop the datanode.   You can do this with ALTER TALBE … DELETE NODE as seen in http://postgres-xc.sourceforge.net/docs/1_1/sql-altertable.html.   This will extract all the rows from the node and redistribute them (as well as others) to the new set of nodes.

List of the nodes where a table is distributed/replicated in pgxc_class.

Regards;
---
Koichi Suzuki

2014/04/02 15:06、Sergio Sinuco <ser...@da...<mailto:ser...@da...>> のメール：

I use pgxc_ctl.

My configuration is:

Node A: 1 gtm master
Node B: 1 gtm_proxy, 1 coordinator, 1 datanode
Node C: 1 gtm_proxy, 1 coordinator, 1 datanode
Node D: 1 gtm slave

First I stopped coordinator and data node from Node C. Then I executed pgxc_ctl remove datanode.... and pgxc_ctl remove coordinator... were ok. But I got "Failed to get pooled connections" message when I tried an insert or update in Node B. I also ran pgxc_pool_reload and restarted the cluster. If I run "SELECT * FROM pgxc_node" in Node B I only have one coordinator and one data node.

The inserts and update commands was ran in a DISTRIBUTE BY REPLICATION table.

2014-04-02 0:32 GMT-05:00 鈴木 幸市 <ko...@in...<mailto:ko...@in...>>:
Did you change your cluster configuration?   Are you using pgxc_ctl or doing configuration/operation manually?

They help to see what’s going on.

Thank you;
---
Koichi Suzuki

2014/04/02 14:02、Sergio Sinuco <ser...@da...<mailto:ser...@da...>> のメール：

Hi. I dropped a coordinator node and a data node from a cluster, but when i try to make an insert or update I have a "Failed to get pooled connections" message. I executed pgxc_pool_reload() but it didn't work. What can I do? I use pgxc 1.1.

--
Sergio E. Sinuco Leon
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--
Sergio E. Sinuco Leon
Arquitecto de soluciones
Datatraffic S.A.S.
Móvil: (57) 310 884 26 50
Fijo (+571) 7426160 Ext 115<tel:%28%2B571%29%207426160%20Ext%20115>
Calle 93 # 15-27 Ofc. 502
Calle 29 # 6 - 94 Ofc. 601
Bogotá, Colombia.
www.datatraffic.com.co<http://www.datatraffic.com.co/>

--
Sergio E. Sinuco Leon
Arquitecto de soluciones
Datatraffic S.A.S.
Móvil: (57) 310 884 26 50
Fijo (+571) 7426160 Ext 115
Calle 93 # 15-27 Ofc. 502
Calle 29 # 6 - 94 Ofc. 601
Bogotá, Colombia.
www.datatraffic.com.co<http://www.datatraffic.com.co/>