In Version 8, during an online reorg (SHRLEVEL REFERENCE or SHLEVEL CHANGE) applying changes to non-partitioned indexes happens in the BUILD2 phase after access has been switched to the second copy of the datasets. The entries in the secondary index that point to rows in the partition being reorged are marked as unavailable until the BUILD2 phase completes. This process could be time consuming and the resulting outage could be a significant problem for applications
In DB2 9, the BUILD2 phase is eliminated for online reorgs. Instead, each partition level reorg will create a shadow copy of the entire NPI and rebuild allentries. This results in greater availability since all shadow datasets may be switched at once. This change happens in DB2 9 Conversion Mode.The new online reorg processing without the BUILD2 phase is required. There is no way to force reorg to process in the Version 8 mode. You should be aware of a few possible ramifications of this change:
•The cost of the REORG will likely increase since the utility is building the entire NPI.
•You will need additional temporary disk space in your storage pool for the shadow data sets of each NPI.
•Since the entire NPI will be built and then switched, it is no longer possible to run reorgs of different parts in separate jobs at the same time.
•If contiguous partitions are being reorged and specified using a range (e.g. PART 2:4) or when SCOPE PENDING is employed, then reorg will use parallelism.