Using dynamic lookup from parallel sessions with synchronized cache in Informatica

Question

Using Informatica 9.1.0

Scenario

Get the Dimension key generated and inserted to the Fact table from the Fact load.

I have to load the Fact table with a dimension key along with other columns. This dimension record is created from within the same mapping. There are five different sessions using the same mapping and executes simultaneously to load the Fact table. In this case I'm using a dynamic lookup with 'Synchronize dynamic cache' enabled to get unique dimension records generated from the 5 sessions using some conditions. The dimension ID is generated using the Sequence-ID in associated expression of the lookup. When a single session alone is run it worked perfectly fine. But when the sessions were run parallely it started to show unique key violation error as random sessions tried to insert the same sequence which was already there.

To fix the issue I had to give persistent lookup cache enabled and Cache file name prefix. But I did not find this solution or this issue in any of the forums or in INFA communities. So not sure this is the right way of doing it or this is a bug of some kind.

Please let me know if you had similar issue or some different thoughts.

Thanks in advance

Answer 1

One other possible solution I can think of is to have the database generate a sequence instead of using Informatica's sequencer. The database should be capable of avoiding any unique key violations.