[pgpool-general: 209] Re: pool_read_message_length2: message length (25) in slot 1 does not match with slot 0(26)

[Tatsuo Ishii]

> I have setup pgpool-II in replication mode with two databases running on
> two ubuntu servers.
> 
> During startup, pgpool logs the following message four (4) times:
> 
> pool_read_message_length2: message length (25) in slot 1 does not match
> with slot 0(26)
> 
> To make sure the two database were in sync, I have cleared both databases
> before I imported new data using pgpool. The problem was still there. I
> then turned on debug (using -d) to see whether there was more information
> and it seems that the warning message is caused by a mismatch between the
> minor version of the two databases.
> 
> 
> 2012-01-30 13:41:19 LOG:   pid 12892: pool_read_message_length2: message
> length (25) in slot 1 does not match with slot 0(26)
> 2012-01-30 13:41:19 DEBUG: pid 12892: 0 th backend: name: server_version
> value: 8.4.10
> 2012-01-30 13:41:19 DEBUG: pid 12892: 1 th backend: name: server_version
> value: 8.4.9
> 
> The difference between the two lengths is 1 (26 - 25) and this is reflected
> in the difference of the minor Postgres versions (8.4.10 and 8.4.9).
> 
> The warning message is gone after I upgraded the 8.4.9 Postgres server to
> 8.4.10.
> 
> Is my observation correct? i.e,, a difference in Postgres (minor) version
> results in a pool_read_message_length2 warning message.

Yes.

> If so, it might be
> a good idea to improve the warning message because it is not immediately
> clear what the problem is.

Yeah, I have to admit that there's a room to improve the log
message. Any volunteer?
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp