Problem creating two connections

[mattwg]

I am struggling to create two connections in a single python program. My use case is that I want to connect to a source database and a target database to move data around. My single program requires both connections to be live at the same time. I am trying to run this code in Python 2.7.5:

    import jaydebeapi as jdbc

    ct = jdbc.connect('com.teradata.jdbc.TeraDriver',
                     ['jdbc:teradata://vivaldi.vip.ebay.com', getpass.getuser(), p[0]],
                     ['/Library/Frameworks/R.framework/Versions/3.1/Resources/library/ebaytd/terajdbc4.jar',
                      '/Library/Frameworks/R.framework/Versions/3.1/Resources/library/ebaytd/tdgssconfig.jar'],)

    cm = jdbc.connect('com.mysql.jdbc.Driver',
                    ['jdbc:mysql://10.9.250.213:3306','root',p[0]],
                    ['/Users/magardner/Documents/Development/R/mysqljdbc/mysql-connector-java-5.1.33-bin.jar'],)

I get an error when the second call to jdbc.connect is made:

Traceback (most recent call last):
  File "/Users/magardner/PycharmProjects/ebayep-backend/process.py", line 82, in <module>
    main()
  File "/Users/magardner/PycharmProjects/ebayep-backend/process.py", line 61, in main
    ['/Users/magardner/Documents/Development/R/mysqljdbc/mysql-connector-java-5.1.33-bin.jar'],)
  File "/Users/magardner/untitled/lib/python2.7/site-packages/jaydebeapi/dbapi2.py", line 269, in connect
    jconn = _jdbc_connect(jclassname, jars, libs, *driver_args)
  File "/Users/magardner/untitled/lib/python2.7/site-packages/jaydebeapi/dbapi2.py", line 116, in _jdbc_connect_jpype
    jpype.JClass(jclassname)
  File "/Users/magardner/untitled/lib/python2.7/site-packages/jpype/_jclass.py", line 58, in JClass
    raise _RUNTIMEEXCEPTION.PYEXC("Class %s not found" % name)
jpype._jexception.RuntimeExceptionPyRaisable: java.lang.RuntimeException: Class com.mysql.jdbc.Driver not found

However if I comment out either of the jdbc.connect statements each runs successfully on it's own and allows me to connect to the relevant database. If I reverse the order of the jdbc.connect statements I still get the error on the second call.

I think this may have something to do with the way that JPype is being reused in the second call. Is this something I am doing wrong? Or is there a known issue here?

Thanks in advance for any suggestions,
Matt

[mattwg]

Typical! I posted the question - had a swig of beer ;-) and realised what might be going on. I can only add the paths for finding the JDBC drivers once - so in effect I have to specify the path for all JDBC drivers my program requires in both calls to jdbc.connect(). So if I change the code to look like this it works a treat:

    import jaydebeapi as jdbc
    ct = jdbc.connect('com.teradata.jdbc.TeraDriver',
                     ['jdbc:teradata://vivaldi.vip.ebay.com', getpass.getuser(), p[0]],
                     ['/Library/Frameworks/R.framework/Versions/3.1/Resources/library/ebaytd/terajdbc4.jar',
                      '/Library/Frameworks/R.framework/Versions/3.1/Resources/library/ebaytd/tdgssconfig.jar',
                      '/Users/magardner/Documents/Development/R/mysqljdbc/mysql-connector-java-5.1.33-bin.jar'],)

    cm = jdbc.connect('com.mysql.jdbc.Driver',
                    ['jdbc:mysql://10.9.250.213:3306','root',p[0]],
                    ['/Library/Frameworks/R.framework/Versions/3.1/Resources/library/ebaytd/terajdbc4.jar',
                      '/Library/Frameworks/R.framework/Versions/3.1/Resources/library/ebaytd/tdgssconfig.jar',
                      '/Users/magardner/Documents/Development/R/mysqljdbc/mysql-connector-java-5.1.33-bin.jar'],)

FIxed! Not sure if this is technically a bug - but I am sure it will catch folks out.

Matt

[baztian]

Thank you Matt, I've opened #2 to find a solution to avoid such problems in the future.
BTW: Your second call to connect() can leave the jar parameter off. It won't get used with the current implementation.

[mattwg]

Thanks. Yeah I figured the second call was redundant this morning!
On Oct 26, 2014 1:04 AM, "baztian" notifications@github.com wrote:

Thank you Matt, I've opened #2 to find a solution to avoid such problems
in the future.
BTW: Your second call to connect() can leave the jar parameter off. It
won't get used with the current implementation.

—
Reply to this email directly or view it on GitHub.

[pybokeh]

This issue is a life saver! I was having the same issue and couldn't figure out why for the longest time. Now I know! I agree that a warning is needed for this.