KNIME 3.7 - DB(Labs): Loading errors, losing settings/content of 3.6.1 workflow DB nodes

Dear Knimler,

upgrading from 3.6.1 to 3.7 I encountered serious problems with the ‘DB Connection(Lab)’ and ‘DB Query Reader(Lab)’ nodes. Openening a WF in 3.7 - which worked fine with 3.6.1 - brings an ‘Error during load’ message - some of the details are:

DB Connector (Labs) 4:1
Loading model settings failed: Config for key “external_to_knime_mapping” not found.
Unable to load port content for node “DB Connector (Labs)”: knimeToExternal
Loading model internals failed: DB Session 772420cb-3408-40c1-b560-cd13c26cef59 is invalid. ORA-01017: invalid username/password; logon denied
State has changed from EXECUTED to CONFIGURED
DB Query Reader (Labs) 4:129
Loading model settings failed: Config for key “external_to_knime_mapping” not found.
Fast Block Reader 4:134
DB Query Reader (Labs) 4:134:133
Loading model settings failed: Config for key “external_to_knime_mapping” not found.
DB Query Reader (Labs) 4:134:120
Loading model settings failed: Config for key “external_to_knime_mapping” not found.
State has changed from CONFIGURED to IDLE
DB Query Reader (Labs) 4:102
Loading model settings failed: Config for key “external_to_knime_mapping” not found.

As a result:

  • All my queries in the ‘DB Query Reader (Labs)’ nodes were lost
  • All the type mapping - here KNIME-Oracle - has to be done from scratch (I think in 3.6.1 a default mapping was provided)

Any chance to get my queries back?


Hi there!

Have you checked settings.xml file of DB Query Reader nodes in your workspace file location?

Have you saved workflow after you opened it with 3.7?


Hi Ivan,

thx for your hint. I hadt a look at these file and found my queries. And after a full restart (PC, KNIME) the DB Nodes got their correct settings/content back. So I assume that it was side-effect of the upgrading process …


1 Like

Glad you found it.

Hello Erich,
unfortunately we had to change the type mapping settings of the new db nodes in a way that they are no longer backward compatible. This can only happen for features that are still in preview in the labs category which is the case for the new db framework and then only if it is really necessary.
With 3.6 we introduced a complete new type mapping framework with the new db framework and received a lot of feedback which caused us to rewritten major parts of it for the 3.7 release.
All nodes that used the previous type mapping implementation (e.g. DB Connector, DB Query Reader, Parameterized DB Query Reader, DB Inserter, …) need to be replaced with a new node from the node repository which unfortunately causes the settings to be lost. We do not expect any further major changes in the new db framework which will cause a similar problem for workflows created with KNIME 3.7 and the production ready version of the framework.
I’m sorry for the inconveniences this problem caused you.