DB2 10.5 for Linux, UNIX, and Windows

Locking and concurrency considerations for online index reorganization

In this topic, online index reorganization applies to an index reorganization that is run with the ALLOW READ ACCESS or ALLOW WRITE ACCESS parameters.

These options allow you to access the table while its indexes are being reorganized. During online index reorganization with the REBUILD option, new indexes are built as additional copies while the original indexes remain intact. Concurrent transactions use the original indexes while the new indexes are created. At the end of the reorganization operation, the original indexes are replaced by the new indexes. Transactions that are committed in the meantime are reflected in the new indexes after the replacement of the original indexes. If the reorganization operation fails and the transaction is rolled back, the original indexes remain intact. During online index reorganization with the CLEANUP and RECLAIM EXTENTS options, space is reclaimed and made available for use for all objects in the table space.

An online index reorganization operation can hold the following locks: