The solution is to increase the VBD heap size. We have in IH_FACT table around 85Million records. For KPI, Campaign will load all the data in IH_FACT table and it ends up with above issues.
We had a SR with PEGA regarding same and the suggestion was to keep the IH_FACT table records to minimum or increase the VBD heap size accordingly. In our case, we foresee the records in IH_FACT table to increase to 200Million...So the recommendation was to have VBD heap size as 16GB for our requirement.