[pgpool-committers: 3905] pgpool: Mega patch to fix "kind mismatch" (or derived) errors in stream

[Tatsuo Ishii]

Mega patch to fix "kind mismatch" (or derived) errors in streaming replication mode.

The errors are caused by wrong prediction in which (or both) database
node will send response to Pgpool-II. Previous implementation using
"sync map" are weak and sometimes fail in the prediction.

This patch introduces new implementation using "pending message
queue", which records all sent message to backends. The element of the
queue stores info regarding messages types
(parse/bind/execute/describe/close/sync), to which database node the
message was sent and so on. It's a simple FIFO queue. When a message
arrives from backend, by looking at the head of the "pending message
queue", it is possible to reliably predict what kind of message and
from which database node it will arrive. After receiving the message,
the element is removed from the queue.

I would like to thank to Sergey Kim, who has been helping me in
testing series of patches.

See bug 271:
http://www.pgpool.net/mantisbt/view.php?id=271

and discussion in pgpool-hackers mailing list [pgpool-hackers: 2043]
and [pgpool-hackers: 2140] for more details.

Branch
------
V3_6_STABLE

Details
-------
http://git.postgresql.org/gitweb?p=pgpool2.git;a=commitdiff;h=18f95017586aacb7254bbccda18ba67c01468483

Modified Files
--------------
src/auth/pool_auth.c                       |  13 +-
src/context/pool_query_context.c           |  80 ++++-
src/context/pool_session_context.c         | 545 +++++++++++++++++++---------
src/include/context/pool_query_context.h   |   3 +-
src/include/context/pool_session_context.h | 107 +++---
src/include/pool.h                         |   2 +
src/include/protocol/pool_proto_modules.h  |   9 +-
src/protocol/CommandComplete.c             | 130 ++++---
src/protocol/pool_process_query.c          | 556 +++++++++++++++--------------
src/protocol/pool_proto_modules.c          | 424 +++++++++++++---------
src/query_cache/pool_memqcache.c           |  12 +-
11 files changed, 1124 insertions(+), 757 deletions(-)