[pgpool-general: 3516] Node disabled problems
james.sewell at lisasoft.com
Mon Mar 16 16:19:19 JST 2015
I am using PGpool on an AWS instance with the following settings:
backend_flag0 = 'ALLOW_TO_FAILOVER'
backend_flag1 = 'ALLOW_TO_FAILOVER'
failover_command = ''
failback_command = ''
fail_over_on_backend_error = off
I am managing failovers from an external product (EDB Enterprise Failover
Manager). This seems to work well most of the time.
Sometimes I get the master node failing because of the AWS network flaking
out on me, this works as expected and I get into the following state:
postgres=# show pool_nodes;
node_id | hostname | port | status | lb_weight | role
0 | 10.51.9.174 | 5432 | 3 | 0.500000 | primary
1 | 10.51.10.173 | 5432 | 2 | 0.500000 | standby
My question is, is there any way in PGPool to automatically re-enable the
primary node when it shows up again? If it *really* went down then my EFM
would fail it over (which runs pcp_promote_node) - so I just want it to
enable it when it shows up again. I can't explain why EFM seems to be more
fault tolerant than PGPool - but I'm ignoring that for now.
I tried using DISALLOW_TO_FAILOVER , but this removes any way of disabling
a single node and stops all PGPool access when I stop the standby node.
This won't work for me. I need to be able to perform the following
- promote a node in PGPool to master (I use pcp_promote_node currently)
- disable a node in PGPool (I use pcp_detach_node currently)
- enable a node I have disabled (I use pcp_enable_node currently)
- Operate on just the master node
- Operate on just the slave node (read only)
I can't seem to find a way to hit all these and still have a functioning
I'm getting the feeling that maybe I can't get all this from PGPool, but
any help would be appreciated. I'm on PGPool 3.3.1
PostgreSQL Team Lead / Solutions Architect
Level 2, 50 Queen St, Melbourne VIC 3000
*P *(+61) 3 8370 8000 *W* www.lisasoft.com *F *(+61) 3 8370 8099
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