[pgpool-committers: 486] pgpool: Fix bug with treatment of BEGIN TRANSACTION in master/slave

[Tatsuo Ishii]

Fix bug with treatment of BEGIN TRANSACTION in master/slave
mode. Original complain is [pgpool-general: 714]. From 3.1, pgpool-II
sends BEGIN.. to all DB nodes. Of course we cannot send BEGIN
TRANSACTION READ WRITE to standby nodes. Problem is, we did not check
BEGIN WORK ISOLATION LEVEL SERIALIZABLE; and sent to standby nodes.
Of course this is wrong, since it's not allowed to run transactions in
serializable mode on standby nodes. So I added check for BEGIN WORK
ISOLATION LEVEL SERIALIZABLE case, with some refactoring because
there's lots of redundant codes.

Branch
------
master

Details
-------
http://git.postgresql.org/gitweb?p=pgpool2.git;a=commitdiff;h=8bd0baeb9c0ca737eca6bd0e77b87e4c51c2fd39

Modified Files
--------------
pool_proto_modules.c |    9 +++---
pool_query_context.c |   69 ++++++++++++++++++++++++++++++++++++++++++--------
pool_query_context.h |    2 +
3 files changed, 64 insertions(+), 16 deletions(-)