[pgpool-hackers: 455] Re: Multi statement query

[Bruce Momjian]

On Tue, Feb 11, 2014 at 07:18:16PM +0900, Tatsuo Ishii wrote:
> Hi pgpool hackers,
> 
> Pgpool-II has a long standing restriction regarding "multi-statement
> query". A multi-statement query is a series of queries separated by
> ";". An example is "BEGIN;SELECT 1;SELECT 2;END". Currently pgpool-II
> sends such a query to primary node only (in streaming replication
> mode) or sends to certain node by just looking at the first query
> ("BEGIN" in the example).
> 
> 1) Analyze each query in a multi-statement query to find a query which
>    needs to be sent to all DB nodes. "BEGIN" or "END" are such query
>    in the example above.
> 
> 2) If such a query is found, sends to all DB nodes.
> 
> 3) Otherwise sends to the primary node.
> 
> This seems to work except following case:
> 
> SET SQL_inheritance TO off; INSERT INTO t1...;
> 
> "SET" needs be sent to all nodes but "INSERT" must only be sent to
> primary node. It seems it's impossible to satify those conditions at a
> same time. Probably it's users fault to create sunch a query...

Are you saying that "SET SQL_inheritance TO off; INSERT INTO t1...;"
comes to the server as a single string?

-- 
  Bruce Momjian  <bruce at momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + Everyone has their own god. +