There was a problem which one can face in high availability environment (clustered) .
We had one Integration between Oracle Ebiz and third party system in which we get data from Oracle Ebiz and send them to third party application. This integration was running fine till the time our server environment upgraded for high availability means clustered ones...
We had two clustered which were configured to be synchronous to idealised HA situation. But this causes one design issue in that Integration.
The issue starts coming in our DB Adapter that now the DB Adapter starting polling Staging table(OEBS) in parallel with the initialised interval. Cluster1 and Cluster2 starts initiating DB Adapter instances in parallel and if we increase the clusters form 2 to 3. The same way three instances of pooling components started. Which leads to a situation in which if we increase the clusters in future from 2 to 50 then in parallel 50 instances of pooling component will be created in parallel and will hit the third party application in parallel. This could be a problem for a target system if it doesn't supports parallel processing.
The solution to this problem was that we need a concept of singleton pattern in our pooling component / DB Adapter.
To enable this feature for high availability environment for a given inbound adapter endpoint, one must add the
singletonJCA service binding property in the
<binding.jca>element and set it to a value of