Re: [Postgres-xc-general] Problem with starting datanode slave

[Juned K. <jkh...@gm...>]

yeah sure i would like to test it first

you mean this presentation
http://sourceforge.net/apps/mediawiki/postgres-xc/index.php?title=PGOpen2013_Postgres_Open_2013
?

On Fri, Apr 18, 2014 at 2:30 PM, 鈴木 幸市 <ko...@in...> wrote:
> No, ALTER TABLE tablename DELETE NODE (nodename);
>
> This is very similar to the thing you should do to add the node
>
> ALTER TABLE table name ADD NODE (ndoename);
>
> It is included in my demo story at the last PG Open presentation.
>
> If you’re not sure, you can test it using smaller work table.
>
> Regards;
> ---
> Koichi Suzuki
>
> 2014/04/18 16:54、Juned Khan <jkh...@gm...> のメール：
>
>> You mean first i have to modify my table structure lets consider i
>> have replicated tables so  i have to remove "DISTRIBUTE by
>> REPLICATION" right ?
>>
>> And then i have to run DROP node command to remove datanode slave
>>
>> pgxc_ctl won't do it for me ?
>> i.e
>> PGXC remove datanode slave datanode1
>>
>> PGXC add datanode slave datanode3 node5 20008 /home/postgres/pgxc/nodes/dn_slave
>>
>> And how it will copy database after adding datanode slave ?
>>
>>
>>
>> On Fri, Apr 18, 2014 at 12:59 PM, 鈴木 幸市 <ko...@in...> wrote:
>>> Reverse order.
>>>
>>> First, exclude removing node from the node set your tables are distributed
>>> or replicated.    You can do this with ALTER TABLE.   All the row in the
>>> table will be redistributed to modified set of nodes for distributed tables.
>>> In the case of replicated tables, tables in the removing node will just be
>>> detached.
>>>
>>> Then, you can issue DROP NODE before you really stop and clear the node
>>> resource.
>>> ---
>>> Koichi Suzuki
>>>
>>> 2014/04/18 16:13、Juned Khan <jkh...@gm...> のメール：
>>>
>>> what if i just remove datanode slave and add it again ? all data will be
>>> copied to slave ?
>>> will it impact on master ?
>>>
>>>
>>> On Fri, Apr 18, 2014 at 6:29 AM, 鈴木 幸市 <ko...@in...> wrote:
>>>>
>>>> The impact to the master server is almost the same as in the case of
>>>> vanilla PG to build a slave using pg_basebackup.   It sends all the master
>>>> database file resource to the slave together with its WAL.   Good thing
>>>> compared with more primitive way of pg_start_backup() and pg_stop_backup()
>>>> is the data are read directly from the cache so impact to I/O workload will
>>>> be smaller.
>>>>
>>>> If you’re concerning safety to the master resource, there could be another
>>>> means, for example, to stop the master, copy everything to the slave, change
>>>> master to enable WAL shipping and slave to run as the slave.   Principally,
>>>> this should work and you can keep the master resource safer but I’ve not
>>>> tested this yet.
>>>>
>>>> Regards;
>>>> ---
>>>> Koichi Suzuki
>>>>
>>>> 2014/04/17 20:23、Juned Khan <jkh...@gm...> のメール：
>>>>
>>>> Hi koichi,
>>>>
>>>> Is there any other short solution to fix this issue ?
>>>>
>>>> 1. Run checkpoint and vacuum full at the master,
>>>>    Found the docs to perform vacuum full but i have confusion about how
>>>> to run checkpoint manually.
>>>>
>>>> 2. Build the slave from the scotch using pg_basebackup (pgxc_ctl provides
>>>> this means).
>>>>    should i run this command from datanode slave server something like (
>>>> pg_basebackup -U postgres -R -D /srv/pgsql/standby --host=192.168.1.17
>>>> --port=5432)
>>>>
>>>> And very important thing how it will impact on datanode master server ? as
>>>> of now i have only this master running on server.
>>>> so as of now i just don't want to take a chance, and somehow want to start
>>>> slave for backup.
>>>>
>>>> Please advice
>>>>
>>>> Regards
>>>> Juned Khan
>>>>
>>>> On Thu, Apr 17, 2014 at 4:43 PM, Juned Khan <jkh...@gm...> wrote:
>>>>>
>>>>> so i have to do experiment for this. i really need that much connection.
>>>>>
>>>>> Thanks for  the suggestion  @Michael
>>>>>
>>>>>
>>>>> On Thu, Apr 17, 2014 at 11:40 AM, Michael Paquier
>>>>> <mic...@gm...> wrote:
>>>>>>
>>>>>> On Thu, Apr 17, 2014 at 2:51 PM, Juned Khan <jkh...@gm...> wrote:
>>>>>>> And i can use pgpool and pgbouncer with pgxc right ?
>>>>>> In front of the Coordinators, that's fine. But I am not sure in from
>>>>>> of the Datanodes as XC has one extra connection parameter to identify
>>>>>> the node type from which connection is from, and a couple of
>>>>>> additional message types to pass down transaction ID, timestamp and
>>>>>> snapshot data from Coordinator to Datanodes (actually Coordinators as
>>>>>> well for DDL queries). If those message types and/or connection
>>>>>> parameters get filtered by pgpool or pgbouncer, well you cannot use
>>>>>> them. I've personally never given a try though, but the idea is worth
>>>>>> an attempt to reduce lock contention that could be caused by a too
>>>>>> high value of max_connections.
>>>>>> --
>>>>>> Michael
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
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>>>>
>>>
>>>
>>>
>>> --
>>
>



-- 
Thanks,
Juned Khan
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