Subject: pgpool Connection issue: ERROR: unable to read message kind

From: Mukesh Tanuku <[email-masked]>
Date: Fri, 20 Dec 2024 15:49:16 +0530

Hello Everyone,

We have a Postgres setup in Azure (IAAS) with 2 DB nodes in the cluster and
pgpool is running on each DB node. We have enabled the watchdog.

What we are doing: We are testing the connectivity to DB cluster via
HammerDB to apply the load.
HammerDB is connecting to Delegate IP via 9999 port.

Issue: when we initiate the connection it gives error, but when we
re-initiate the connection again then it is successful. What could be the
issue

Error message we are seeing when we initiate the connection for the first
time.

Error in Virtual User 1: Error: Connection to database failed
connection to server at "10.35.8.4", port 9999 failed: ERROR:  unable to
read message kind
DETAIL:  kind does not match between main(53) slot[1] (45)

If you want to see any configuration settings that i made, i can share.

Please help me in this regard.

Thank you
Mukesh Tanuku

---

From: Tatsuo Ishii <[email-masked]>
Date: Mon, 23 Dec 2024 11:13:50 +0900 (JST)

> Please help me in this regard.

The error message can be interpreted that primary PostgreSQL sent 0x53
= 'S'(parameter status message) while standby sent 0x45 = 'E' (error
response). Perhaps the parameter status cannot be processed on standby
for some reasons. In order to study the cause of error, I need a
pgpool log with debug level 1 (log_min_messages = debug1). Can you
provide it?

BTW, cross posting pgpool-general and pgsql-general is not
recommended. Please post to pgpool-general only next time.

Best reagards,
--
Tatsuo Ishii
SRA OSS K.K.
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp