[pgpool-general: 9300] Re: pgpool Connection issue: ERROR: unable to read message kind

[Mukesh Tanuku]

Hello Tatsuo,

I have few questions, If you again look back the pgpool.log

at 2024-12-23 04:17:00.310: [unknown] pid 1227285: DETAIL:  SSLRequest from
client, there is connection to DB and
at 2024-12-23 04:17:00.392: [unknown] pid 1227285: DETAIL:  destination = 0
for query= "CREATE DATABASE "tpcc" OWNER "tpcc""
query got fired to create database tpcc

again there is new connection at 2024-12-23 04:17:00.653: [unknown] pid
1227285: DETAIL:  SSLRequest from client
then this connection got failed with error message

Questions:
1. what is the destination = 0 means
2. How can we see which backend node got selected while the connection got
established?
3. According to your recommendation i have set synchronous commit, but this
parameter *synchronous_commit = on, *but still failing (intermittently). So
is the replication delay might be purely on Azure networking?

 Regards
Mukesh Tanuku




On Mon, Dec 23, 2024 at 5:01 PM Tatsuo Ishii <ishii at postgresql.org> wrote:

> > Thanks Tatsuo for giving a response to my ask.
> >
> > *doubt:* Is this because we set a Asynchronous streaming replication on
> > postgresql nodes?
>
> Yeah, that's a legitimate explanation.
>
> tpcc database was created at 2024-12-23 04:17:00.392.
>
> > 2024-12-23 04:17:00.392: [unknown] pid 1227285: DETAIL:  destination = 0
> > for query= "CREATE DATABASE "tpcc" OWNER "tpcc""
>
> 273 ms after the error occured.
>
> > 2024-12-23 04:17:00.665: [unknown] pid 1227285: LOG:  pool_read_kind:
> error
> > message from 1 th backend:database "tpcc" does not exist
>
> Probably 273 ms was not enough to replicate the tpcc database.  You
> could avoid the error by using synchronous streaming replication with
> synchronous_commit = remote_apply option.
>
> Best reagards,
> --
> Tatsuo Ishii
> SRA OSS K.K.
> English: http://www.sraoss.co.jp/index_en/
> Japanese:http://www.sraoss.co.jp
>
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