[pgpool-general: 2935] Re: pool members are reporting different backend states
Tatsuo Ishii
ishii at postgresql.org
Fri Jun 20 16:47:53 JST 2014
Attila,
If you restart pgpool-II and the backend status which pgpool-II
recognizes is different from actual PostgreSQL's staus, then it is
likely that you stop or restart PostgreSQL between pgpool-II stops and
restarts. In another other word, you directly changed backend situation
without let pgpool-II notices it. i.e. your fault.
Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp
> Yep, "service pgpool2 force-reload" has corrected this, but I am not happy
> at all.
>
> I thought that the pool status is consistent among the members. If pgpool
> does the replication, it is a disaster to have different backend sets in
> the pool members!
> No way to keep databases consistent... One pool will write just one
> backend, the other will write both.
>
> Attila
>
>
> 2014-06-19 12:08 GMT+02:00 Yugo Nagata <nagata at sraoss.co.jp>:
>
>> Hi,
>>
>> On Thu, 19 Jun 2014 11:05:32 +0200
>> Attila Heidrich <attila.heidrich at gmail.com> wrote:
>>
>> > Dear Guys,
>> >
>> > How on earth it is possible, that the pool members reports different
>> > backend status? It will cause problems very soon I guess.
>>
>> It is possible if pgpool reads old backend status info when this starts up.
>> pgpool will discard the old backend info when starts with -D option.
>>
>> However, it would be better pgpools can detect the status mismatch
>> between them in some way.
>>
>> >
>> > Node: 1
>> > Host: 10.100.1.11
>> > Port: 5433
>> > Weight: 0.500000
>> > Status: Up, in pool (1)
>> > WD status: Standby (2)
>> >
>> > Node: 2
>> > Host: 10.100.1.10
>> > Port: 5433
>> > Weight: 0.500000
>> > Status: Up, in pool (1)
>> >
>> > ---
>> >
>> > Node: 1
>> > Host: 10.100.1.11
>> > Port: 5433
>> > Weight: 0.500000
>> > Status: Up, detached from pool (3)
>> > WD status: Standby (2)
>> >
>> > Node: 2
>> > Host: 10.100.1.10
>> > Port: 5433
>> > Weight: 0.500000
>> > Status: Up, in pool (1)
>> > WD status: Standby (2)
>> >
>> > ---
>> >
>> > Node: 1
>> > Host: 10.100.1.11
>> > Port: 5433
>> > Weight: 0.500000
>> > Status: Up, in pool (1)
>> > WD status: Standby (2)
>> >
>> > Node: 2
>> > Host: 10.100.1.10
>> > Port: 5433
>> > Weight: 0.500000
>> > Status: Up, in pool (1)
>> > WD status: Active (3)
>> >
>> > ---
>> >
>> > Node: 1
>> > Host: 10.100.1.11
>> > Port: 5433
>> > Weight: 0.500000
>> > Status: Up, in pool (1)
>> > WD status: Standby (2)
>> >
>> > Node: 2
>> > Host: 10.100.1.10
>> > Port: 5433
>> > Weight: 0.500000
>> > Status: Up, in pool (1)
>> > WD status: Standby (2)
>> >
>> > ---
>> >
>> > Node: 1
>> > Host: 10.100.1.11
>> > Port: 5433
>> > Weight: 0.500000
>> > Status: Up, detached from pool (3)
>> > WD status: Standby (2)
>> >
>> > Node: 2
>> > Host: 10.100.1.10
>> > Port: 5433
>> > Weight: 0.500000
>> > Status: Up, in pool (1)
>> > WD status: Active (3)
>> >
>> > I have got five pool members, two of them are the backends themselves.
>> >
>> > Every pool member has the other 4 as other_pgpool, and
>> > heartbeat_destination, and the same two backend servers, here is the
>> > relevant part of the config for all pool members:
>> >
>> >
>> > nor-openfire-1:
>> > backend_hostname1 = '10.100.1.11'
>> > backend_port1 = 5433
>> > backend_weight1 = 1
>> > backend_data_directory1 = '/var/lib/postgresql/9.3'
>> > backend_flag1 = 'ALLOW_TO_FAILOVER'
>> > backend_hostname2 = '10.100.1.10'
>> > backend_port2 = 5433
>> > backend_weight2 = 1
>> > backend_data_directory2 = '/var/lib/postgresql/9.3'
>> > backend_flag2 = 'ALLOW_TO_FAILOVER'
>> > fail_over_on_backend_error = on
>> > heartbeat_destination0 = 'nor-postgres-2'
>> > heartbeat_destination_port0 = 9694
>> > other_pgpool_hostname0 = 'nor-postgres-2'
>> > other_pgpool_port0 = 5432
>> > heartbeat_destination1 = 'nor-jboss-2'
>> > heartbeat_destination_port1 = 9694
>> > other_pgpool_hostname1 = 'nor-jboss-2'
>> > other_pgpool_port1 = 5432
>> > heartbeat_destination2 = 'nor-postgres-1'
>> > heartbeat_destination_port2 = 9694
>> > other_pgpool_hostname2 = 'nor-postgres-1'
>> > other_pgpool_port2 = 5432
>> > heartbeat_destination3 = 'nor-jboss-1'
>> > heartbeat_destination_port3 = 9694
>> > other_pgpool_hostname3 = 'nor-jboss-1'
>> > other_pgpool_port3 = 5432
>> > nor-postgres-1:
>> > backend_hostname1 = '10.100.1.11'
>> > backend_port1 = 5433
>> > backend_weight1 = 1
>> > backend_data_directory1 = '/var/lib/postgresql/9.3'
>> > backend_flag1 = 'ALLOW_TO_FAILOVER'
>> > backend_hostname2 = '10.100.1.10'
>> > backend_port2 = 5433
>> > backend_weight2 = 1
>> > backend_data_directory2 = '/var/lib/postgresql/9.3'
>> > backend_flag2 = 'ALLOW_TO_FAILOVER'
>> > fail_over_on_backend_error = on
>> > heartbeat_destination0 = 'nor-postgres-2'
>> > heartbeat_destination_port0 = 9694
>> > other_pgpool_hostname0 = 'nor-postgres-2'
>> > other_pgpool_port0 = 5432
>> > heartbeat_destination1 = 'nor-jboss-2'
>> > heartbeat_destination_port1 = 9694
>> > other_pgpool_hostname1 = 'nor-jboss-2'
>> > other_pgpool_port1 = 5432
>> > heartbeat_destination2 = 'nor-openfire-1'
>> > heartbeat_destination_port2 = 9694
>> > other_pgpool_hostname2 = 'nor-openfire-1'
>> > other_pgpool_port2 = 5432
>> > heartbeat_destination3 = 'nor-jboss-1'
>> > heartbeat_destination_port3 = 9694
>> > other_pgpool_hostname3 = 'nor-jboss-1'
>> > other_pgpool_port3 = 5432
>> > nor-postgres-2:
>> > backend_hostname1 = '10.100.1.11'
>> > backend_port1 = 5433
>> > backend_weight1 = 1
>> > backend_data_directory1 = '/var/lib/postgresql/9.3'
>> > backend_flag1 = 'ALLOW_TO_FAILOVER'
>> > backend_hostname2 = '10.100.1.10'
>> > backend_port2 = 5433
>> > backend_weight2 = 1
>> > backend_data_directory2 = '/var/lib/postgresql/9.3'
>> > backend_flag2 = 'ALLOW_TO_FAILOVER'
>> > fail_over_on_backend_error = on
>> > heartbeat_destination0 = 'nor-jboss-2'
>> > heartbeat_destination_port0 = 9694
>> > other_pgpool_hostname0 = 'nor-jboss-2'
>> > other_pgpool_port0 = 5432
>> > heartbeat_destination1 = 'nor-openfire-1'
>> > heartbeat_destination_port1 = 9694
>> > other_pgpool_hostname1 = 'nor-openfire-1'
>> > other_pgpool_port1 = 5432
>> > heartbeat_destination2 = 'nor-postgres-1'
>> > heartbeat_destination_port2 = 9694
>> > other_pgpool_hostname2 = 'nor-postgres-1'
>> > other_pgpool_port2 = 5432
>> > heartbeat_destination3 = 'nor-jboss-1'
>> > heartbeat_destination_port3 = 9694
>> > other_pgpool_hostname3 = 'nor-jboss-1'
>> > other_pgpool_port3 = 5432
>> > nor-jboss-1:
>> > backend_hostname1 = '10.100.1.11'
>> > backend_port1 = 5433
>> > backend_weight1 = 1
>> > backend_data_directory1 = '/var/lib/postgresql/9.3'
>> > backend_flag1 = 'ALLOW_TO_FAILOVER'
>> > backend_hostname2 = '10.100.1.10'
>> > backend_port2 = 5433
>> > backend_weight2 = 1
>> > backend_data_directory2 = '/var/lib/postgresql/9.3'
>> > backend_flag2 = 'ALLOW_TO_FAILOVER'
>> > fail_over_on_backend_error = on
>> > heartbeat_destination0 = 'nor-postgres-2'
>> > heartbeat_destination_port0 = 9694
>> > other_pgpool_hostname0 = 'nor-postgres-2'
>> > other_pgpool_port0 = 5432
>> > heartbeat_destination1 = 'nor-jboss-2'
>> > heartbeat_destination_port1 = 9694
>> > other_pgpool_hostname1 = 'nor-jboss-2'
>> > other_pgpool_port1 = 5432
>> > heartbeat_destination2 = 'nor-openfire-1'
>> > heartbeat_destination_port2 = 9694
>> > other_pgpool_hostname2 = 'nor-openfire-1'
>> > other_pgpool_port2 = 5432
>> > heartbeat_destination3 = 'nor-postgres-1'
>> > heartbeat_destination_port3 = 9694
>> > other_pgpool_hostname3 = 'nor-postgres-1'
>> > other_pgpool_port3 = 5432
>> > nor-jboss-2:
>> > backend_hostname1 = '10.100.1.11'
>> > backend_port1 = 5433
>> > backend_weight1 = 1
>> > backend_data_directory1 = '/var/lib/postgresql/9.3'
>> > backend_flag1 = 'ALLOW_TO_FAILOVER'
>> > backend_hostname2 = '10.100.1.10'
>> > backend_port2 = 5433
>> > backend_weight2 = 1
>> > backend_data_directory2 = '/var/lib/postgresql/9.3'
>> > backend_flag2 = 'ALLOW_TO_FAILOVER'
>> > fail_over_on_backend_error = on
>> > heartbeat_destination0 = 'nor-postgres-2'
>> > heartbeat_destination_port0 = 9694
>> > other_pgpool_hostname0 = 'nor-postgres-2'
>> > other_pgpool_port0 = 5432
>> > heartbeat_destination1 = 'nor-openfire-1'
>> > heartbeat_destination_port1 = 9694
>> > other_pgpool_hostname1 = 'nor-openfire-1'
>> > other_pgpool_port1 = 5432
>> > heartbeat_destination2 = 'nor-postgres-1'
>> > heartbeat_destination_port2 = 9694
>> > other_pgpool_hostname2 = 'nor-postgres-1'
>> > other_pgpool_port2 = 5432
>> > heartbeat_destination3 = 'nor-jboss-1'
>> > heartbeat_destination_port3 = 9694
>> > other_pgpool_hostname3 = 'nor-jboss-1'
>> > other_pgpool_port3 = 5432
>> >
>> > Other question:
>> >
>> > Our servers are connected via two networks. Is it possible to specify a
>> > pool member with both IP interfaces?
>>
>> One other pgpool must be specified by single IP or hostname. You can use
>> either
>> of them. The exception is heartbeat destination; you can specify both IP
>> as heartbeat_destinationX.
>>
>> >
>> >
>> ----------------------------------------------------------------------------------------
>> > Network #1
>> > | | | |
>> > |
>> > S1 S2 S3 S4
>> S5
>> > | | | |
>> > |
>> >
>> ----------------------------------------------------------------------------------------
>> > Network #2
>> >
>> > none of the networks are connected with failover connections, both use
>> > different IP subnets.
>> >
>> > Regards,
>> >
>> > Attila
>>
>>
>> --
>> Yugo Nagata <nagata at sraoss.co.jp>
>>
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