Database connection causing nodes to hang


I’m using the new database ports and I think I’m experiencing the following:

  1. Create a connection (MySQL Connector in my case)
  2. Run a DB Table Selector then DB Reader
  3. After some time reset the DB Table Selector and try to run again. Node then gets stuck as “Copying input object at port 1”.

Between steps 2 and 3 the computer has hibernated, not sure if this is required to trigger though.

It looks like the connection has died and isn’t recreated. If I reset the MySQL Connector all works fine again.

It would be nicer if the node threw an error when a connection can’t be established rather than hanging?

I have the “Restore database connection” ticked but the node description doesn’t say what this does, I expected it to create a new connection automatically if it’s lost?




Hi @swebb -

Maybe this recent topic is related? Not sure if the solution might apply in your case…

Mmm possibly a solution but it feels like knime should be checking if the connection is valid and throwing an error / creating a new connection if it isn’t?

It’s not in valid state and will never execute so shouldn’t indicate that it is and instead should fail with an appropriate error if a new one can’t be reestablished?

Though I haven’t looked at the underlying implementation so my expectation may not line up with others.



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