← Back to team overview

openlp-core team mailing list archive

  1. openlp-core team
  2. Mailing list archive
  3. Message #19218

[Bug 1117334] [NEW] can't open/preview a song if db connection is interrupted (mysql)

  Thread Previous • Date Previous • • Thread Next 
Public bug reported:

Hi.

Discovered the following error if OpenLP looses a connection to MySQL.

Scenario: OpenLP configured to use MySQL instead of SQLite.
Environment: Ubuntu 10.04 LTS, localhost for MySQL.

On starting OpenLP, it holds open two connections to MySQL. These are
seen as having growing 'sleep' durations in MySQL by executing "show
process" whilst OpenLP is dormant/not using the DB.

If there is a connection issue, either due to a network timeout, or
forced connection kill - of at least one of these two persistent
connections, when opening/previewing a song in the GUI, the following
debug is displayed:

Traceback (most recent call last):
  File "/usr/lib/pymodules/python2.6/openlp/core/lib/mediamanageritem.py", line 474, in onDoubleClicked
    self.onPreviewClick()
  File "/usr/lib/pymodules/python2.6/openlp/core/lib/mediamanageritem.py", line 496, in onPreviewClick
    serviceItem = self.buildServiceItem()
  File "/usr/lib/pymodules/python2.6/openlp/core/lib/mediamanageritem.py", line 590, in buildServiceItem
    if self.generateSlideData(serviceItem, item, xmlVersion, remote):
  File "/usr/lib/pymodules/python2.6/openlp/plugins/songs/lib/mediaitem.py", line 501, in generateSlideData
    song = self.plugin.manager.get_object(Song, item_id)
  File "/usr/lib/pymodules/python2.6/openlp/core/lib/db.py", line 323, in get_object
    return self.session.query(object_class).get(key)
  File "/usr/lib/pymodules/python2.6/sqlalchemy/orm/query.py", line 507, in get
    return self._get(key, ident)
  File "/usr/lib/pymodules/python2.6/sqlalchemy/orm/query.py", line 1500, in _get
    return q.all()[0]
  File "/usr/lib/pymodules/python2.6/sqlalchemy/orm/query.py", line 1267, in all
    return list(self)
  File "/usr/lib/pymodules/python2.6/sqlalchemy/orm/query.py", line 1361, in __iter__
    return self._execute_and_instances(context)
  File "/usr/lib/pymodules/python2.6/sqlalchemy/orm/query.py", line 1364, in _execute_and_instances
    result = self.session.execute(querycontext.statement, params=self._params, mapper=self._mapper_zero_or_none())
  File "/usr/lib/pymodules/python2.6/sqlalchemy/orm/session.py", line 753, in execute
    clause, params or {})
  File "/usr/lib/pymodules/python2.6/sqlalchemy/engine/base.py", line 824, in execute
    return Connection.executors[c](self, object, multiparams, params)
  File "/usr/lib/pymodules/python2.6/sqlalchemy/engine/base.py", line 872, in _execute_clauseelement
    parameters=params
  File "/usr/lib/pymodules/python2.6/sqlalchemy/engine/base.py", line 938, in __create_execution_context
    return dialect.execution_ctx_cls(dialect, connection=self, **kwargs)
  File "/usr/lib/pymodules/python2.6/sqlalchemy/engine/default.py", line 170, in __init__
    self.cursor = self.create_cursor()
  File "/usr/lib/pymodules/python2.6/sqlalchemy/engine/default.py", line 258, in create_cursor
    return self._connection.connection.cursor()
  File "/usr/lib/pymodules/python2.6/sqlalchemy/engine/base.py", line 576, in connection
    raise exc.InvalidRequestError("Can't reconnect until invalid transaction is rolled back")
InvalidRequestError: Can't reconnect until invalid transaction is rolled back

Note that this was initially seen after OpenLP was left running, and
therefore connected to MySQL, overnight. After the overnight period, an
attempt was made to open/preview a song and the above error was
displayed. At this stage I don't know why the connections were closed -
the server was localhost, the db uptime is days, and there was no laptop
suspend during the overnight period.

Thoughts on why it can't reconnect correctly?

To recreate, configure OpenLP to use a MySQL database (not forgetting,
on ubuntu, to install the package python-mysqldb otherwise you get
"module not found" errors), and configuring the [songs] section for
mysql, as described on the FAQ wiki page.

Then start OpenLP and observe output of "show process", or use the
"processes" tab if using phpmyadmin to observe the database server. Kill
one or both connections. Attempt to open/preview a song, and the result
is as above.


npf@pc-n993019:~$ dpkg --list|grep openlp
ii  openlp                                   1.9.12+bzr2117-0ubuntu1~lucid1                        Church lyrics projection application

--d.

** Affects: openlp
     Importance: Undecided
         Status: New


** Tags: connection mysql openlp

-- 
You received this bug notification because you are a member of OpenLP
Core, which is subscribed to OpenLP.
https://bugs.launchpad.net/bugs/1117334

Title:
  can't open/preview a song if db connection is interrupted (mysql)

Status in OpenLP - Worship Presentation Software:
  New

Bug description:
  Hi.

  Discovered the following error if OpenLP looses a connection to MySQL.

  Scenario: OpenLP configured to use MySQL instead of SQLite.
  Environment: Ubuntu 10.04 LTS, localhost for MySQL.

  On starting OpenLP, it holds open two connections to MySQL. These are
  seen as having growing 'sleep' durations in MySQL by executing "show
  process" whilst OpenLP is dormant/not using the DB.

  If there is a connection issue, either due to a network timeout, or
  forced connection kill - of at least one of these two persistent
  connections, when opening/previewing a song in the GUI, the following
  debug is displayed:

  Traceback (most recent call last):
    File "/usr/lib/pymodules/python2.6/openlp/core/lib/mediamanageritem.py", line 474, in onDoubleClicked
      self.onPreviewClick()
    File "/usr/lib/pymodules/python2.6/openlp/core/lib/mediamanageritem.py", line 496, in onPreviewClick
      serviceItem = self.buildServiceItem()
    File "/usr/lib/pymodules/python2.6/openlp/core/lib/mediamanageritem.py", line 590, in buildServiceItem
      if self.generateSlideData(serviceItem, item, xmlVersion, remote):
    File "/usr/lib/pymodules/python2.6/openlp/plugins/songs/lib/mediaitem.py", line 501, in generateSlideData
      song = self.plugin.manager.get_object(Song, item_id)
    File "/usr/lib/pymodules/python2.6/openlp/core/lib/db.py", line 323, in get_object
      return self.session.query(object_class).get(key)
    File "/usr/lib/pymodules/python2.6/sqlalchemy/orm/query.py", line 507, in get
      return self._get(key, ident)
    File "/usr/lib/pymodules/python2.6/sqlalchemy/orm/query.py", line 1500, in _get
      return q.all()[0]
    File "/usr/lib/pymodules/python2.6/sqlalchemy/orm/query.py", line 1267, in all
      return list(self)
    File "/usr/lib/pymodules/python2.6/sqlalchemy/orm/query.py", line 1361, in __iter__
      return self._execute_and_instances(context)
    File "/usr/lib/pymodules/python2.6/sqlalchemy/orm/query.py", line 1364, in _execute_and_instances
      result = self.session.execute(querycontext.statement, params=self._params, mapper=self._mapper_zero_or_none())
    File "/usr/lib/pymodules/python2.6/sqlalchemy/orm/session.py", line 753, in execute
      clause, params or {})
    File "/usr/lib/pymodules/python2.6/sqlalchemy/engine/base.py", line 824, in execute
      return Connection.executors[c](self, object, multiparams, params)
    File "/usr/lib/pymodules/python2.6/sqlalchemy/engine/base.py", line 872, in _execute_clauseelement
      parameters=params
    File "/usr/lib/pymodules/python2.6/sqlalchemy/engine/base.py", line 938, in __create_execution_context
      return dialect.execution_ctx_cls(dialect, connection=self, **kwargs)
    File "/usr/lib/pymodules/python2.6/sqlalchemy/engine/default.py", line 170, in __init__
      self.cursor = self.create_cursor()
    File "/usr/lib/pymodules/python2.6/sqlalchemy/engine/default.py", line 258, in create_cursor
      return self._connection.connection.cursor()
    File "/usr/lib/pymodules/python2.6/sqlalchemy/engine/base.py", line 576, in connection
      raise exc.InvalidRequestError("Can't reconnect until invalid transaction is rolled back")
  InvalidRequestError: Can't reconnect until invalid transaction is rolled back

  Note that this was initially seen after OpenLP was left running, and
  therefore connected to MySQL, overnight. After the overnight period,
  an attempt was made to open/preview a song and the above error was
  displayed. At this stage I don't know why the connections were closed
  - the server was localhost, the db uptime is days, and there was no
  laptop suspend during the overnight period.

  Thoughts on why it can't reconnect correctly?

  To recreate, configure OpenLP to use a MySQL database (not forgetting,
  on ubuntu, to install the package python-mysqldb otherwise you get
  "module not found" errors), and configuring the [songs] section for
  mysql, as described on the FAQ wiki page.

  Then start OpenLP and observe output of "show process", or use the
  "processes" tab if using phpmyadmin to observe the database server.
  Kill one or both connections. Attempt to open/preview a song, and the
  result is as above.

  
  npf@pc-n993019:~$ dpkg --list|grep openlp
  ii  openlp                                   1.9.12+bzr2117-0ubuntu1~lucid1                        Church lyrics projection application

  --d.

To manage notifications about this bug go to:
https://bugs.launchpad.net/openlp/+bug/1117334/+subscriptions

Follow ups

References

  Thread Previous • Date Previous • • Thread Next