[pgpool-general: 8767] Difference between pgpool 'primary' and Watchdog 'MASTER' versus the 'load_balance_node'
Gopikrishnan
nksgopikrishnan at gmail.com
Mon May 15 19:24:53 JST 2023
Hi folks,
Need your help in clearing a confusion regd. basic terminologies:
Regd. which I couldn't gather much from the docs at:
https://www.pgpool.net/docs/pgpool-II-4.0.4/
1. primary
2. MASTER
3. load_balance_node
I have a pgpool with 3 nodes. I have a confusion between the pgpool primary and
the watchdog *MASTER* and the `*load_balance_node*`
In my setup, the pgpool primary node (according to show pool_nodes output)
is : *10.108.104.31, *and also the node designated *load_balance_node*.
While the MASTER node, according to pgpool watchdog, is: *10.108.104.32* And
the *cluster virtual IP* is attached to this node.
I have the following questions in mind:
1. What do the terms '*primary*' and '*MASTER*' and *load_balance_node*
mean?
2. During failover, Is the '*primary*' or '*MASTER*' or '
*load_balance_node* failure taken into account?
3. What is the difference (or any relation) between the '*primary*' and '
*MASTER*' and *load_balance_node* nodes?
4. If the cluster virtual IP is on the non '*primary*' node, wouldn't it
affect the performance of the HA setup?
Below are the outputs for *show pool_nodes *and* watchdog *info:
psql -h delegateIP -p 9999 -U pgpool postgres -c "show pool_nodes"
Password for user pgpool:
node_id | hostname | port | status | lb_weight | role |
select_cnt | load_balance_node | replication_delay |
last_status_change---------+---------------+------+--------+-----------+---------+------------+-------------------+-------------------+---------------------
0 | 10.108.104.31 | 5432 | up | 0.333333 | primary | 0
| true | 0 | 2023-05-12 12:07:13
1 | 10.108.104.32 | 5432 | up | 0.333333 | standby | 0
| false | 0 | 2023-05-12 12:07:13
2 | 10.108.104.33 | 5432 | down | 0.333333 | standby | 0
| false | 0 | 2023-05-12 12:07:13
(3 rows)
And the Watchdog info:
pcp_watchdog_info -h localhost -vw -U pgpool
Watchdog Cluster Information
Total Nodes : 3
Remote Nodes : 2
Quorum state : QUORUM EXIST
Alive Remote Nodes : 2
VIP up on local node : NO
Master Node Name : vm-104-32.eng.dev.com:9999 Linux vm-104-32.eng.dev.com
Master Host Name : 10.108.104.32
Watchdog Node Information
Node Name : vm-104-31.eng.dev.com:9999 Linux vm-104-31.eng.dev.com
Host Name : vm-104-31.eng.dev.com
Delegate IP : 10.108.104.34
Pgpool port : 9999
Watchdog port : 9000
Node priority : 1
Status : 7
Status Name : STANDBY
Node Name : vm-104-32.eng.dev.com:9999 Linux vm-104-32.eng.dev.com
Host Name : 10.108.104.32
Delegate IP : 10.108.104.34
Pgpool port : 9999
Watchdog port : 9000
Node priority : 1
Status : 4
Status Name : MASTER
Node Name : vm-104-33.eng.dev.com:9999 Linux vm-104-33.eng.dev.com
Host Name : 10.108.104.33
Delegate IP : 10.108.104.34
Pgpool port : 9999
Watchdog port : 9000
Node priority : 1
Status : 7
Status Name : STANDBY
*Thanks & Regards*
*Gopi*
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