Invalidate cache when data refreshed using external process

Question

Hi all, I have some reference tables that are loaded in memory using cache. I have some external processes - sql scripts - that refreshes these tables. I would like to have a mechanism to notify the cache that the underlined tables have been refreshed.
What options do we have here? I was thinking at using some jms notifications to the cache.
Did you encounter this requirement before?
Thanks.

Answer 1

Hello.
One way to do this is to create a shadow table, who is updated via triggers corresponding to change events on the master table. Next, you need to write and start an "update thread" whose purpose is to poll that table and update the cache accordingly. In order to prevent echo-ing, you will need to include a last updating process column in both the master and the shadow table. That will prevent updates orginating from your cache from infinitely recursing. Essentially, your "update thread" will need to ignore rows created by the write/through or behind mechanism of your cache.
I hope this helps,
-Adrian