[Postgres-xc-bugs] Incomplete transaction clean up during pgxc_lock_for_backup violation

[Víctor D. M. O. <vda...@gm...>]

Greetings to everyone, I'm new to the mail list,

I was testing master branch of postgres-xc, and I think exist a strange
behavior during transaction redo when Postgres-XC is violated trying to
create a database while pgxc_lock_for_backup is active.

GIT commit:

$ git log | tail | grep ^commit
commit d31084e9d1118b25fd16580d9d8c2924b5740dff
$ git branch -vv
* master a50bdd3 [origin/master] Replace strndup calls by strdup in makesgml

$ uname -a
Linux eva-01-nerv-seele 3.11.7-200.fc19.x86_64 #1 SMP Mon Nov 4 14:09:03
UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

 ~/.opt/pgxc/bin/initgtm -D ~/.opt/pgxc/var/lib/pgsql/data_gtm
 ~/.opt/pgxc/bin/initdb -D ~/.opt/pgxc/var/lib/pgsql/data_datanode2
--nodename datanode2
 ~/.opt/pgxc/bin/initdb -D ~/.opt/pgxc/var/lib/pgsql/data_datanode1
--nodename datanode1
 ~/.opt/pgxc/bin/initdb -D ~/.opt/pgxc/var/lib/pgsql/data_coord1 --nodename
coord1

~/.opt/pgxc/bin/gtm -D ~/.opt/pgxc/var/lib/pgsql/data_gtm
~/.opt/pgxc/bin/postgres --coordinator -D
~/.opt/pgxc/var/lib/pgsql/data_coord1
~/.opt/pgxc/bin/postgres --datanode -D
~/.opt/pgxc/var/lib/pgsql/data_datanode1 -p 15432


$ ~/.opt/pgxc/bin/psql postgres
psql (PGXC 1.1devel, based on PG 9.2beta2)
Type "help" for help.

postgres=# CREATE NODE datanode1 WITH (TYPE = 'datanode', PORT = 15432);
CREATE NODE
postgres=# select pgxc_pool_reload();
 pgxc_pool_reload
------------------
 t
(1 row)

postgres=# select * from pg_prepared_xacts ;
 transaction | gid | prepared | owner | database
-------------+-----+----------+-------+----------
(0 rows)

postgres=# select pgxc_lock_for_backup();
INFO:  please do not close this session until you are done adding the new
node
 pgxc_lock_for_backup
----------------------
 t
(1 row)

postgres=# select txid_current();
 txid_current
--------------
        10011
(1 row)

postgres=# create database test;
PANIC:  we seem to have dropped a bit somewhere
PANIC:  we seem to have dropped a bit somewhere
The connection to the server was lost. Attempting reset: Failed.
!> \q

--- LOGS IN DIRECTOR ---
LOG:  server process (PID 23684) was terminated by signal 6: Aborted
DETAIL:  Failed process was running: create database test;
LOG:  terminating any other active server processes
WARNING:  terminating connection because of crash of another server process
DETAIL:  The postmaster has commanded this server process to roll back the
current transaction and exit, because another server process exited
abnormally and possibly corrupted shared memory.
HINT:  In a moment you should be able to reconnect to the database and
repeat your command.
FATAL:  the database system is in recovery mode
LOG:  all server processes terminated; reinitializing
LOG:  database system was interrupted; last known up at 2013-11-11 21:38:21
COT
LOG:  database system was not properly shut down; automatic recovery in
progress
LOG:  redo starts at 0/189C940
LOG:  record with zero length at 0/189CB18
LOG:  redo done at 0/189C940
LOG:  recovering prepared transaction 10012
LOG:  database system is ready to accept connections
LOG:  autovacuum launcher started
---

$ ~/.opt/pgxc/bin/psql postgres
psql (PGXC 1.1devel, based on PG 9.2beta2)
Type "help" for help.

postgres=# select * from pg_prepared_xacts ;
 transaction |  gid   |           prepared            | owner | database
-------------+--------+-------------------------------+-------+----------
       10012 | T10012 | 2013-11-11 21:38:22.246206-05 | vdmo  | postgres
(1 row)

postgres=# rollback prepared 'T10012';
ERROR:  prepared transaction with identifier "T10012" does not exist

Unfortunately from here not is possible to rollback or commit the
transaction, and not allow run again pgxc_lock_for_backup because exists a
transaction in prepare stage.

Excuse my ignorance but is this a problem or normal expected behavior?.

Thks,

Daniel.