postgres-xc-general

[Postgres-xc-general] postgres-xc 0.9.5: Do not have a GTM snapshot available / Failed to get pooled connection

[David H. <dav...@me...>]

Hi all,

I'm experimenting a bit with postgres-xc 0.9.5 on debian squeeze, with a 
build from the 0.9.5 sources. I think I've set up a cluster with three 
hw systems, two nodes (data node/coordinator each) and a gtm node, 
properly, following the installation manual.

However, the data nodes complain when they are started, every so many 
seconds: "WARNING:  Do not have a GTM snapshot available". And when I 
connect to a coordinator and try to execute 'CREATE DATABASE mydb;', I 
get the message: "ERROR:  Failed to get pooled connections". I've 
attached the configuration files that I am using for coordinator and 
datanode (the difference between nodes 1 and 2 being only that 
pgxc_node_id is 1 and 2 respectively). The GTM is started with "$GTM -x 
628 -p 5000 -D $DATADIR -l $LOGFILE &".

Any suggestions what I should do or try?

Greetings,
David

Re: [Postgres-xc-general] postgres-xc 0.9.5: Do not have a GTM snapshot available / Failed to get pooled connection

[Lionel F. <lio...@gm...>]

Hello,

(from my own experience) ensure that nothing is blocking incoming
connections (like tcpwrappers => /etc/hosts.allow, /etc/hosts.deny, or
firewall). ACL of pg_ha.conf could be part of the solution there.

You could ensure everything is connected correctly by issuing 'netstat -apn'
on each node, and looking for ESTABLISHED connections from/to GTM port and
coordinator ports.

Regards

Lionel Frachon

2011/7/8 David Hartveld <dav...@me...>

> Hi all,
>
> I'm experimenting a bit with postgres-xc 0.9.5 on debian squeeze, with a
> build from the 0.9.5 sources. I think I've set up a cluster with three hw
> systems, two nodes (data node/coordinator each) and a gtm node, properly,
> following the installation manual.
>
> However, the data nodes complain when they are started, every so many
> seconds: "WARNING:  Do not have a GTM snapshot available". And when I
> connect to a coordinator and try to execute 'CREATE DATABASE mydb;', I get
> the message: "ERROR:  Failed to get pooled connections". I've attached the
> configuration files that I am using for coordinator and datanode (the
> difference between nodes 1 and 2 being only that pgxc_node_id is 1 and 2
> respectively). The GTM is started with "$GTM -x 628 -p 5000 -D $DATADIR -l
> $LOGFILE &".
>
> Any suggestions what I should do or try?
>
> Greetings,
> David
>
>
> ------------------------------------------------------------------------------
> All of the data generated in your IT infrastructure is seriously valuable.
> Why? It contains a definitive record of application performance, security
> threats, fraudulent activity, and more. Splunk takes this data and makes
> sense of it. IT sense. And common sense.
> http://p.sf.net/sfu/splunk-d2d-c2
> _______________________________________________
> Postgres-xc-general mailing list
> Pos...@li...
> https://lists.sourceforge.net/lists/listinfo/postgres-xc-general
>
>

Re: [Postgres-xc-general] postgres-xc 0.9.5: Do not have a GTM snapshot available / Failed to get pooled connection

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

Hi

On Fri, Jul 8, 2011 at 9:04 PM, David Hartveld <dav...@me...>wrote:

> Hi all,
>
> I'm experimenting a bit with postgres-xc 0.9.5 on debian squeeze, with a
> build from the 0.9.5 sources. I think I've set up a cluster with three hw
> systems, two nodes (data node/coordinator each) and a gtm node, properly,
> following the installation manual.
>
> However, the data nodes complain when they are started, every so many
> seconds: "WARNING:  Do not have a GTM snapshot available".
>
This bug is related with autovacuum launcher which is not able to get a
valid snapshot from GTM. I am studying this test case and may have a fix for
that next week.

> And when I connect to a coordinator and try to execute 'CREATE DATABASE
> mydb;', I get the message: "ERROR:  Failed to get pooled connections". I've
> attached the configuration files that I am using for coordinator and
> datanode (the difference between nodes 1 and 2 being only that pgxc_node_id
> is 1 and 2 respectively). The GTM is started with "$GTM -x 628 -p 5000 -D
> $DATADIR -l $LOGFILE &".
>
Your configuration files look OK.
However, a datanode is a node that do not interact with other nodes through
a connection pooling, so you do not need to set data_node_hosts,
data_node_ports, pooler_port in its configuration file. num_data_nodes also
in unnecessary


> Any suggestions what I should do or try?
>
Have you started your nodes with -i option so as they accept TCP-IP
connections?
As Lionel said, pg_hba.conf setting is full of traps. You should check that
also.

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

Re: [Postgres-xc-general] postgres-xc 0.9.5: Do not have a GTM snapshot available / Failed to get pooled connection

[Abbas B. <abb...@te...>]

Hi,
I noticed that you have given 2 as pgxc_node_id in both the files you have
attached. Please make sure you have given different numbers to all the 4
nodes.

Another suggestion from my side will be to give IP address of GTM instead of
host name pg-db-01.

Regards
Abbas

On Fri, Jul 8, 2011 at 5:04 PM, David Hartveld <dav...@me...>wrote:

> Hi all,
>
> I'm experimenting a bit with postgres-xc 0.9.5 on debian squeeze, with a
> build from the 0.9.5 sources. I think I've set up a cluster with three hw
> systems, two nodes (data node/coordinator each) and a gtm node, properly,
> following the installation manual.
>
> However, the data nodes complain when they are started, every so many
> seconds: "WARNING:  Do not have a GTM snapshot available". And when I
> connect to a coordinator and try to execute 'CREATE DATABASE mydb;', I get
> the message: "ERROR:  Failed to get pooled connections". I've attached the
> configuration files that I am using for coordinator and datanode (the
> difference between nodes 1 and 2 being only that pgxc_node_id is 1 and 2
> respectively). The GTM is started with "$GTM -x 628 -p 5000 -D $DATADIR -l
> $LOGFILE &".
>
> Any suggestions what I should do or try?
>
> Greetings,
> David
>
>
> ------------------------------------------------------------------------------
> All of the data generated in your IT infrastructure is seriously valuable.
> Why? It contains a definitive record of application performance, security
> threats, fraudulent activity, and more. Splunk takes this data and makes
> sense of it. IT sense. And common sense.
> http://p.sf.net/sfu/splunk-d2d-c2
> _______________________________________________
> Postgres-xc-general mailing list
> Pos...@li...
> https://lists.sourceforge.net/lists/listinfo/postgres-xc-general
>
>

Re: [Postgres-xc-general] postgres-xc 0.9.5: Do not have a GTM snapshot available / Failed to get pooled connection

[David H. <dav...@me...>]

Op 11-07-11 07:17, Abbas Butt schreef:
> I noticed that you have given 2 as pgxc_node_id in both the files you
> have attached. Please make sure you have given different numbers to all
> the 4 nodes.

I need a little clarification for this point. In the installation manual 
is suggested that pgxc_node_id is the index into the coordinator_hosts 
and coordinator_ports arrays, as well as into datanode_hosts / 
datanode_ports. But you suggest i assign unique numbers to each node. If 
it should be the latter, this could be improved in the installation manual.

> Another suggestion from my side will be to give IP address of GTM
> instead of host name pg-db-01.

Done. I'm not sure this is necessary, as the log file of the GTM shows 
incoming connections on startup of each of the four nodes.

David

Re: [Postgres-xc-general] postgres-xc 0.9.5: Do not have a GTM snapshot available / Failed to get pooled connection

[David H. <dav...@me...>]

Op 11-07-11 11:22, David Hartveld schreef:
> Op 11-07-11 07:17, Abbas Butt schreef:
>> I noticed that you have given 2 as pgxc_node_id in both the files you
>> have attached. Please make sure you have given different numbers to all
>> the 4 nodes.
>
> I need a little clarification for this point. In the installation manual
> is suggested that pgxc_node_id is the index into the coordinator_hosts
> and coordinator_ports arrays, as well as into datanode_hosts /
> datanode_ports. But you suggest i assign unique numbers to each node. If
> it should be the latter, this could be improved in the installation manual.

Following up on my own post, coordinators and data nodes each have their 
own sequence of index numbers, all starting at 1, up to n (the number of 
coordinators and data nodes respectively).

After pointing the correct indices to the correct hosts (in the 
coordinator_hosts and data_node_hosts arrays), I've gotten the 
distributed cluster to create a database on one node, and to connect to 
it to the other. I'm now going to try to run a more extensive test, and 
will let you know the results if anything interesting happens ;-)

Thank you all for your help,
David Hartveld

Re: [Postgres-xc-general] postgres-xc 0.9.5: Do not have a GTM snapshot available / Failed to get pooled connection

[David H. <dav...@me...>]

Op 09-07-11 04:13, Michael Paquier schreef:
> Hi
>
> On Fri, Jul 8, 2011 at 9:04 PM, David Hartveld
> <dav...@me... <mailto:dav...@me...>> wrote:
>
>     Hi all,
>
>     I'm experimenting a bit with postgres-xc 0.9.5 on debian squeeze,
>     with a build from the 0.9.5 sources. I think I've set up a cluster
>     with three hw systems, two nodes (data node/coordinator each) and a
>     gtm node, properly, following the installation manual.
>
>     However, the data nodes complain when they are started, every so
>     many seconds: "WARNING: Do not have a GTM snapshot available".
>
> This bug is related with autovacuum launcher which is not able to get a
> valid snapshot from GTM. I am studying this test case and may have a fix
> for that next week.

Is it a symptom of the nodes not being able to connect to the coordinators?

>
>     And when I connect to a coordinator and try to execute 'CREATE
>     DATABASE mydb;', I get the message: "ERROR: Failed to get pooled
>     connections". I've attached the configuration files that I am using
>     for coordinator and datanode (the difference between nodes 1 and 2
>     being only that pgxc_node_id is 1 and 2 respectively). The GTM is
>     started with "$GTM -x 628 -p 5000 -D $DATADIR -l $LOGFILE &".
>
> Your configuration files look OK.
> However, a datanode is a node that do not interact with other nodes
> through a connection pooling, so you do not need to set data_node_hosts,
> data_node_ports, pooler_port in its configuration file. num_data_nodes
> also in unnecessary
>
>
>     Any suggestions what I should do or try?
>
> Have you started your nodes with -i option so as they accept TCP-IP
> connections?

They already were, but I actually configured the wrong hostnames. I've 
now reconfigured with the correct IPs.

> As Lionel said, pg_hba.conf setting is full of traps. You should check
> that also.

"host all all samenet trust" should do the trick, I guess?

Thanks for your input!
David

Re: [Postgres-xc-general] postgres-xc 0.9.5: Do not have a GTM snapshot available / Failed to get pooled connection

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

On Mon, Jul 11, 2011 at 6:22 PM, David Hartveld
<dav...@me...>wrote:

> Op 09-07-11 04:13, Michael Paquier schreef:
>
>> Hi
>>
>> On Fri, Jul 8, 2011 at 9:04 PM, David Hartveld
>> <dav...@me... <mailto:david.hartveld@mendix.**com<dav...@me...>>>
>> wrote:
>>
>>    Hi all,
>>
>>    I'm experimenting a bit with postgres-xc 0.9.5 on debian squeeze,
>>    with a build from the 0.9.5 sources. I think I've set up a cluster
>>    with three hw systems, two nodes (data node/coordinator each) and a
>>    gtm node, properly, following the installation manual.
>>
>>    However, the data nodes complain when they are started, every so
>>    many seconds: "WARNING: Do not have a GTM snapshot available".
>>
>> This bug is related with autovacuum launcher which is not able to get a
>> valid snapshot from GTM. I am studying this test case and may have a fix
>> for that next week.
>>
>
> Is it a symptom of the nodes not being able to connect to the
> coordinators?
>
Snapshots and GXIDs are fed from GTM. So it is not directly related.
It is a problem with the internal process autovacuum is using to try to get
a snapshot from GTM, and is not related at all with your setting problems.


>
>
>
>>    And when I connect to a coordinator and try to execute 'CREATE
>>    DATABASE mydb;', I get the message: "ERROR: Failed to get pooled
>>    connections". I've attached the configuration files that I am using
>>    for coordinator and datanode (the difference between nodes 1 and 2
>>    being only that pgxc_node_id is 1 and 2 respectively). The GTM is
>>    started with "$GTM -x 628 -p 5000 -D $DATADIR -l $LOGFILE &".
>>
>> Your configuration files look OK.
>> However, a datanode is a node that do not interact with other nodes
>> through a connection pooling, so you do not need to set data_node_hosts,
>> data_node_ports, pooler_port in its configuration file. num_data_nodes
>> also in unnecessary
>>
>>
>>    Any suggestions what I should do or try?
>>
>> Have you started your nodes with -i option so as they accept TCP-IP
>> connections?
>>
>
> They already were, but I actually configured the wrong hostnames. I've now
> reconfigured with the correct IPs.

OK, that's cool if it works.

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