hi all,
I observed that only one database writer in a workflow is active and all others are waiting. The same is observed if I introduce multiple database connections. Is there any way to activate a concurrent use for this node?
Hi,
currently KNIME uses only one connection per user and database. However we plan to introduce better connection handling which will allow you to write in parallel.
To speedup the writing process you can increase the batch size in the advanced tab of the Database Writer dialog. The default value is 1 which results in a lot of network roundtrips. By increasing the batch size you reduce the network roundtrips but the node consumes more memory since the batch is cached in memory before it is send to the database.
Bye,
Tobias
Hello, has anything chaged since Tobias' reply in Aug 2015? Is there any way to run multiple queries concurrently (other than using different user accounts)?
Best wishes,
Michal
+1 also for faster reading
I currently use the database reader to retrieve monitoring data that is transformed in a lengthy process. Therefore it would be nice to have multiple connections to speed this up. Otherwise the server is not using its full capacity (1 connection = 1 core only at 100%). My current workaround is to pass a list of users to use (=pool) that I pass to the database connector as flowvariable so that I get dedicated, simultanous connections using the parallel chunk loop. This results in a major speedup (and a heavy server load).
Hello, has anything changed since Tobias' reply in Aug 2016?
Is there any way to run multiple queries concurrently (other than using different user accounts)?