[pgpool-general: 1384] Re: PgPool 3.2.2 doesn't appear to be load balancing

[web at mr-paradox.net]

Looks like I had to clear the node status, pgpool thought that my slave node was 
down.

On Mon, Feb 11, 2013 at 03:13:29PM -0800, web at mr-paradox.net wrote:
- pgpool-II version 3.2.2 (namameboshi), CentOS
- 
- My configuration is currently like this
- master_slave_mode = on             # (change requires restart)
- master_slave_sub_mode = 'stream'   # (change requires restart)
- 
- sr_check_period = 10
- sr_check_user = 'nobody'
- sr_check_password = 'n0b0dy'
- delay_threshold = 10000000
- 
- backend_hostname0 = master
- backend_port0 = 5432
- backend_weight0 = 0
- backend_data_directory0 = '/db/pg'
- backend_flag0 = 'ALLOW_TO_FAILOVER'
- 
- backend_hostname1 = slave
- backend_port1 = 5432
- backend_weight1 = 1
- backend_data_directory1 = '/db/pg'
- backend_flag1 = 'ALLOW_TO_FAILOVER'
- 
- All reads and writes are currently going to the master.
- 
- load_balance_mode = on
- ignore_leading_white_space = on
- white_function_list = ''
- black_function_list = 'currval,lastval,nextval,setval'
- 
- I've read the FAQ:
- 
- > It seems my pgpool-II does not do load balancing. Why?
- > First of all, pgpool-II' load balancing is "session base", not "statement base". That means, DB node
- > selection for load balancing is decided at the beginning of session. So all SQL statements are sent to the
- > same DB node until the session ends.
- 
- To mitigate this I have a low client_idle_limit, since rails will attempt to retain it's own pool.
- I'd love an opinion on this.
- 
- > Another point is, whether statement is in an explicit transaction or not. If the statement is in a
- > transaction, it will not be load balanced in the replication mode. In pgpool-II 3.0 or later, SELECT will be
- > load balanced even in a transaction if operated in the master/slave mode.
- 
- I read this as: in version >3 that I should expect to see SELECTs load balanced in master/slave mode.
- 
- > Note the method to choose DB node is not LRU or some such. Pgpool-II chooses DB node randomly considering
- > the "weight" parameter in pgpool.conf. This means that the chosen DB node is not uniformly distributed among
- > DB nodes in short term. You might want to inspect the effect of load balancing after ~100 queries have been
- > sent.
- 
- I set the weight for the master to 0 in hopes that basically all non-writes go to the slave.
- 
- 
- Any help would be great, if i can debug, or log anything I'd be happy to do so. (nothing particularly
- useful is in the current logs)
- 
- Thanks