[pgpool-general: 308] Re: Transaction replicated to streaming slave

[Tatsuo Ishii]

Pgpool-II does not support multi statement query.

begin;delete from channels where hostname='';delete from channels where hostname='';commit;

So pgpool only analyzes the first component of the multi statement
query. i.e. "begin". This is a known limitation and clearly stated in
pgpool's document.

Also it seems you use very old client. I notice this from the log:

> 2012-03-26 20:07:08 DEBUG: pid 19119: pool_read_string: read all from

pool_read_string is only called if client use old version 2 protocol,
which was used by PostgreSQL 7.3 or older. I recommend to use more
modern client software.
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp

> Hello everyone,
> 
> 
> I'm finding that pgpool is replicating transactions to the streaming
> slave, even though I believe I've configured pgpool to only communicate
> with the master.
> 
> I've verified the log on the slave, and it is indeed receiving that
> transaction;
> 
> If I shut down the slave and re-run the query, everything proceeds normally.
> 
> Does anyone have any advice?
> 
> Thanks,
> Bill
> 
> pgpool-II-3.1.2
> postgresql-server-9.1.1
> 
> Log:
> --------------
> 2012-03-26 20:07:08 DEBUG: pid 19119: statement2: begin;delete from
> channels where hostname='';delete from channels where hostname='';commit;
> 
> 2012-03-26 20:07:08 DEBUG: pid 19119: pool_set_query_in_progress: done
> 
> 2012-03-26 20:07:08 DEBUG: pid 19119: send_to_where: 3 query:
> begin;delete from channels where hostname='';delete from channels where
> hostname='';commit;
> 
> 2012-03-26 20:07:08 DEBUG: pid 19119: wait_for_query_response: waiting
> for backend 0 completing the query
> 
> 2012-03-26 20:07:08 DEBUG: pid 19119: wait_for_query_response: waiting
> for backend 1 completing the query
> 
> 2012-03-26 20:07:08 DEBUG: pid 19119: read_kind_from_backend: read kind
> from 0 th backend C NUM_BACKENDS: 2
> 
> 2012-03-26 20:07:08 DEBUG: pid 19119: read_kind_from_backend: read kind
> from 1 th backend C NUM_BACKENDS: 2
> 
> 2012-03-26 20:07:08 DEBUG: pid 19119: ProcessBackendResponse: kind from
> backend: C
> 
> 2012-03-26 20:07:08 DEBUG: pid 19119: pool_read_string: read all from
> pending data. po:7 len:29
> 
> 2012-03-26 20:07:08 DEBUG: pid 19119: pool_read_string: read all from
> pending data. po:7 len:60
> 
> 2012-03-26 20:07:08 DEBUG: pid 19119: CompletedResponse: string: "BEGIN"
> 
> 2012-03-26 20:07:08 DEBUG: pid 19119: read_kind_from_backend: read kind
> from 0 th backend C NUM_BACKENDS: 2
> 
> 2012-03-26 20:07:08 DEBUG: pid 19119: read_kind_from_backend: read kind
> from 1 th backend E NUM_BACKENDS: 2
> 
> 2012-03-26 20:07:08 ERROR: pid 19119: read_kind_from_backend: 1 th kind
> E does not match with master or majority connection kind C
> 
> 2012-03-26 20:07:08 DEBUG: pid 19119: pool_read_string: read all from
> pending data. po:66 len:1
> 
> 2012-03-26 20:07:08 ERROR: pid 19119: kind mismatch among backends.
> Possible last query was: "begin;delete from channels where
> hostname='';delete from channels where hostname='';commit;" kind details
> are: 0[C] 1[E: ERROR:  cannot execute DELETE in a read-only transaction
> ]
> 
> 2012-03-26 20:07:08 LOG:   pid 19119: do_child: exits with status 1 due
> to error
> --------------
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