[Postgres-xc-general] Uncommited transaction? Weird issues with DDL and missing database

[Artur G. <aa...@bo...>]

Hi, 

I just finished the multi-master configuration of Postgres XC on my
test environment (three virtual machines):  

* VM1 - with GTM only
* VM2,
VM2 - two masters with one data-node and one coordinator on each machine


I tried to create some databases on each master to check if everything
works ok, but I found a strange issue with one database that had been
created only on one of the masters (while other databases I created and
deleted afterwards were ok): 

postgres=# l
 List of databases
 Name |
Owner | Encoding | Collate | Ctype | Access privileges

-----------+----------+----------+-------------+-------------+-----------------------

postgres | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | 
 template0 |
postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/postgres +
 | | | | |
postgres=CTc/postgres
 template1 | postgres | UTF8 | en_US.UTF-8 |
en_US.UTF-8 | =c/postgres +
 | | | | | postgres=CTc/postgres
 test2 |
postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | 
 whatnot | postgres | UTF8 |
en_US.UTF-8 | en_US.UTF-8 |  

vs 

postgres=# l
 List of databases
 Name |
Owner | Encoding | Collate | Ctype | Access privileges

-----------+----------+----------+-------------+-------------+-----------------------

postgres | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | 
 template0 |
postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/postgres +
 | | | | |
postgres=CTc/postgres
 template1 | postgres | UTF8 | en_US.UTF-8 |
en_US.UTF-8 | =c/postgres +
 | | | | | postgres=CTc/postgres
 whatnot |
postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 |  

Unfortunately, when I try
to perform any DDL command on a server that sees "test2" database I receive
the following errors: 

postgres=# drop database test2;
ERROR: database
"test2" does not exist
postgres=# create database test2;
ERROR: database
"test2" already exists 

Also, when I try to remove another database called
"whatnot", drop operation never finishes. It looks like a transaction that
hangs some DDL operations: 

postgres=# select * from pgxc_prepared_xacts;

pgxc_prepared_xact 
--------------------
 T74589
(1 row)

postgres=# select
* from pg_prepared_xacts;
 transaction | gid | prepared | owner | database

-------------+--------+-------------------------------+----------+----------

73716 | T73716 | 2015-07-09 12:58:25.823385+02 | postgres | postgres
(1
row)

postgres=#  

When I try to rollback the transaction, Postgres says
that given GID does not exist. 

Is it a bug in Postgres XC? Is there a way
to synchronize the masters? (eg delete "test2" on one master and "whatnot"
on both of them). Please keep in mind that I created/dropped more databases
without any issues, so I'm unsure what went wrong in case of these two
specific databases. 

Cheers, 

Artur