[pgpool-general: 2353] Re: Problems with recovered master node.
Tatsuo Ishii
ishii at postgresql.org
Fri Dec 20 08:28:25 JST 2013
> Hi.
>
> It wasn't installed, but I installed it and had the same result.
Can you show the PostgreSQL around "ROLLBACK"?
> By the way, to install it I just need to execute this right?
> CREATE EXTENSION pgpool_regclass;
Yes.
Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp
> On 18/12/13 18:17, Tatsuo Ishii wrote:
>> Have you installed pgpool_regclass?
>>
>> Best regards,
>> --
>> Tatsuo Ishii
>> SRA OSS, Inc. Japan
>> English: http://www.sraoss.co.jp/index_en.php
>> Japanese: http://www.sraoss.co.jp
>>
>>> Hi everyone.
>>>
>>> I'm having an issue with pgpool.
>>> First of all my configuration:
>>> 1 Server with pgpool-II version 3.3.2 (tokakiboshi)
>>> 3 Servers with:
>>> postgresql93-contrib-9.3.2-1PGDG.rhel6.x86_64
>>> postgresql93-devel-9.3.2-1PGDG.rhel6.x86_64
>>> postgresql93-libs-9.3.2-1PGDG.rhel6.x86_64
>>> postgresql93-9.3.2-1PGDG.rhel6.x86_64
>>> postgresql93-server-9.3.2-1PGDG.rhel6.x86_64
>>>
>>> All 4 servers are RHEL 6 machines. (Amazon AMI's actually)
>>>
>>> Pgpool is configured to have Master/Slave Nodes with replication
>>> and Load Balancing.
>>>
>>> #------------------------------------------------------------------------------
>>> # LOAD BALANCING MODE
>>> #------------------------------------------------------------------------------
>>>
>>> load_balance_mode = on
>>> # Activate load balancing mode
>>> # (change requires restart)
>>> ignore_leading_white_space = on
>>> # Ignore leading white spaces of each
>>> query
>>> white_function_list = ''
>>> # Comma separated list of function names
>>> # that don't write to database
>>> # Regexp are accepted
>>> black_function_list = 'nextval,setval'
>>> # Comma separated list of function names
>>> # that write to database
>>> # Regexp are accepted
>>>
>>>
>>> #------------------------------------------------------------------------------
>>> # MASTER/SLAVE MODE
>>> #------------------------------------------------------------------------------
>>>
>>> master_slave_mode = on
>>> # Activate master/slave mode
>>> # (change requires restart)
>>> master_slave_sub_mode = 'stream'
>>> # Master/slave sub mode
>>> # Valid values are combinations slony or
>>> # stream. Default is slony.
>>> # (change requires restart)
>>>
>>> # - Streaming -
>>>
>>> sr_check_period = 1
>>> # Streaming replication check period
>>> # Disabled (0) by default
>>> sr_check_user = 'postgres'
>>> # Streaming replication check user
>>> # This is necessary even if you disable
>>> # streaming replication delay check with
>>> # sr_check_period = 0
>>> sr_check_password = ''
>>> # Password for streaming replication
>>> check user
>>> delay_threshold = 1
>>> # Threshold before not dispatching
>>> query to standby node
>>> # Unit is in bytes
>>> # Disabled (0) by default
>>>
>>> # - Special commands -
>>>
>>> follow_master_command = '/bin/follow_master.sh %d %h %D %m %H %R'
>>> # Executes this command after master
>>> failover
>>> # Special values:
>>> # %d = node id
>>> # %h = host name
>>> # %p = port number
>>> # %D = database cluster path
>>> # %m = new master node id
>>> # %H = hostname of the new master node
>>> # %M = old master node id
>>> # %P = old primary node id
>>> # %r = new master port number
>>> # %R = new master database cluster path
>>> # %% = '%' character
>>>
>>>
>>> #All three nodes are configured like this
>>> backend_hostnamen = 'ip_node_n'
>>> backend_portn = 5432
>>> backend_weightn = 0
>>> backend_data_directoryn = '/var/lib/pgsql/9.3/data/'
>>> backend_flagn = 'ALLOW_TO_FAILOVER'
>>>
>>> I'm using repmgr to handle the replication in the nodes.
>>>
>>>
>>> My problem occurs when I kill the master node, everything works as
>>> expected and a slave takes it's place.
>>> My application continues working with no major issues until I decide to
>>> recover the dead master node.
>>>
>>> After that pgool starts sending this message:
>>> 2013-12-18 17:19:07 LOG: pid 30801: do_child: exits with status 1 due
>>> to error
>>> 2013-12-18 17:19:10 LOG: pid 30802: pool_send_and_wait: Error or
>>> notice message from backend: : DB node id: 0 backend pid: 27585
>>> statement: ROLLBACK message: there is no transaction in progress
>>> 2013-12-18 17:19:10 ERROR: pid 30802: read_kind_from_backend: 1 th kind
>>> C does not match with master or majority connection kind N
>>> 2013-12-18 17:19:10 ERROR: pid 30802: kind mismatch among backends.
>>> Possible last query was: "ROLLBACK" kind details are: 0[N: there is no
>>> transaction in progress] 1[C]
>>>
>>> And I identified that the problem is that pgpool is sending a rollback
>>> to the old master node [node 0] (Something illegal as far as I know) and
>>> then all the transaction is cancelled and my application fails.
>>> If I promote the old master again, then the application works with no
>>> problem.
>>>
>>> Anyone has an idea why is this ocurring?
>>>
>>> Regards!
>>>
>>>
>>>
>>> --
>>>
>>>
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>
>
> --
>
>
> Be aware that if you reply directly to this message, your reply may not be
> secure. Do not send us communications that contain unencrypted confidential
> information such as passwords, account numbers, or Social Security numbers.
>
> This message, including any attachments, is for the sole use of the
> intended recipient(s) and may contain confidential and privileged
> information. If you are not the intended recipient, please destroy all
> copies of this message and any attachments. In addition, please notify
> Gazzang immediately by email to info at gazzang.com.
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