RTV-20003: Warning: Cannot perform Partition Exchange Loading

Question

Hi,
We have a unique situation in which the data has to be loaded 4 times each month to the fact table. The fact table is partitioned by month. We have configured the mappings so that DIRECT is false and REPLACE DATA option is also false (so that we don't loose exisiting data, if any). When the data is loaded to the fact for the first time then PEL is performed but when data is loaded for 2nd, 3rd and 4th time in the current partition OWB issues a warning (RTV-20003). We understand that in these cases data is still loaded but without using PEL. Is there any way to force OWB to perform PEL all 4 times without lossing the exisiting data in the current partition?
Thanks, Yashu

Answer 1

Hi, you can't use PEL to add data to an existing partition: by definition PEL swaps the rows in a regular, non-partitioned table with the rows in 1 partition of a partitioned table. Or better said, it swaps the table data segment with the partition data segment, and possibly the corresponding index segments if the indexes match and the part.table indexes are local. This means you are not really moving any rows so you can't add any to the partition using PEL.
As a safety net, OWB provides "replace data = false" by default so you don't trash your data.
If the 4 loads/month are 1 per week, you can consider creating e.g. 4 week partitions instead of month partitions. OWB PEL can't handle weeks: if you follow this route you should disable OWB PEL and exchange partitions 'by hand' inside a stored procedure called in the postmapping. This can be worth if you have really big volumes or if you want to feed your fact table very fast, staging new rows and then swapping them in almost instantaneously. You should evaluate your index rebuild speed requirements too.
Hope this helps, Antonio