Problem with paralell execution of DatabaseReader Nod in the same workflow

KNIME Analytics Platform
1

Hi all,

I use Database Reader Node for read  milion of row from Oracle Database 11g.

I want execute at the same time mutiple query an the join the result.

The problem is that only one node is reading rows from db, the other are waiting the end of the node that is reading rows.

How you can view in the attached pricture 

Correntisti is reading rows

Clienti is waiting the previous node finishs

It's possible execute the node in parallel?

thank you for help

Giorgio

 

The driver I'm using is (ojdbc6.jar) "<entry key="driver" type="xstring" value="oracle.jdbc.driver.OracleDriver"/>

2

Reading in parallel from the same databases usually doesn't work reliably and can cause all kinds of problems. Therefore the DB connection is only used by a single node at a time. We try to improve this in the next release.

3

ok

thankYou for answer

see you soon

Giorgio

4

Hi,

I've solved this problem changing Knime.ini file.

I've added this row:

 

-Dknime.async.io.cachesize=50000
-Dknime.database.fetchsize=50000
-Dknime.database.enable.concurrency=false
 

So Knime opens a cursor for time then fetch seem executein  in parallel on multiple nodes.

 

Thats good for  me

see you soon

Giorgio