Hi pgpool hackers,
I'm heading to release 2.2 on this December. Followings is the release
note I want to include the release. Please let me know if I have
missed something or left "must fix" things.
--
Tatsuo Ishii
SRA OSS, Inc. Japan
2.2 2008/12/?
* Version 2.2
This version enhances on line recovery and includes important
fixes for serializable transactions which could cause data
inconsistency among DB nodes.
* New features
- Add client_idle_limit_in_recovery directive. This will
prevent 2nd stage in online recovery from not going foward
by idle clients sitting forever(Tatsuo)
- Allow to load balance DECLARE, FETCH and CLOSE(Tatsuo)
* Bug fixes
- Close all file descriptors when running in daemon mode.
Otherwise we inherit sockets from apache when it's started by
pgpoolAdmin. This results in that port 80 is occupied for
example. Pach provided by Akio Ishida. Also add
chdir("/"). This is always good for daemon programs(Tatsuo)
- Allow MD5 authentication in raw mode as stated in
docs(Tatsuo)
- Check transaction serialization failure error in
serializable mode and abort all nodes if so. Otherwise we
allow data inconsistency among DB nodes(Tatsuo).
See following scenario: (M:master, S:slave)
M:S1:BEGIN;
M:S2:BEGIN;
S:S1:BEGIN;
S:S2:BEGIN;
M:S1:SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
M:S2:SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
S:S1:SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
S:S2:SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
M:S1:UPDATE t1 SET i = i + 1;
S:S1:UPDATE t1 SET i = i + 1;
M:S2:UPDATE t1 SET i = i + 1; <-- blocked
S:S1:COMMIT;
M:S1:COMMIT;
M:S2:ERROR: could not serialize access due to
concurrent update
S:S2:UPDATE t1 SET i = i + 1; <-- success in UPDATE and
data becomes inconsistent!
* Incompatible changes
- Always fail over and restart all children. Before we do
restart only if master has not been changed. This is
wrong. If we have trouble with network cable or something,
TCP/IP stack keeps on retrying for long time and the only
way to prevent it is restarting process(Tatsuo)
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