Re: pgpool not load balancing via foreign table - Mailing list pgsql-admin

From Sbob
Subject Re: pgpool not load balancing via foreign table
Date
Msg-id b0292ac1-67e8-48c2-b59d-9cdecc4d93e2@quadratum-braccas.com
Whole thread Raw
In response to Re: pgpool not load balancing via foreign table  ("David G. Johnston" <david.g.johnston@gmail.com>)
List pgsql-admin


On 6/21/24 11:12 PM, David G. Johnston wrote:
On Friday, June 21, 2024, David G. Johnston <david.g.johnston@gmail.com> wrote:
On Friday, June 21, 2024, Sbob <sbob@quadratum-braccas.com> wrote:

however no matter how many selects I run via the foreign tables a "show pool_nodes" on the pgpool server shows  a select_cnt of 0 for all 3 nodes.

If I connect to the pgpool server/cluster and run a number of select statements then a "show pool_nodes"  shows increasing values for all 3 backend nodes for select_cnt


It appears that a foreign table / FDW connection to a pgpool node does not trigger the collection of any load balancing stats


Skimming over the project and the extension (for the first time ever…) it seems pgpool only does stats in response to Execute messages while FDW is using the simple query protocol.  That pgpool doesn’t do stats for Query as well seems like an oversight.

Nevermind…or at least while possible further reading of the pgpool code doesn’t support it - the simple query case is present.

David J.
 

Im not sure what the 'simple query protocol' is, is this an option when setting up a FDW/Foreign Table? Or is this something that pgpool just does not support?


I also ran a test where I set all 3 backend nodes to have 'log_min_duration_statement = 0' and I ran a tail on the logs for all 3 backend data nodes while I ran a series of selects via a new connection to the FDW database for each select. And I only see selects logged in the logfile of the master/primary backend db.


Is there anything I can do to force the load balancing?



pgsql-admin by date:

Previous
From: Muhammad Ikram
Date:
Subject: Re: My Database getting dropped anonymously
Next
From: Wasim Devale
Date:
Subject: Restoration