On a distributed system, or in a system where reporting databases are regularly rotated, it may be necessary to merge multiple reporting databases together so that full reports can be generated. Merging databases will transfer all tables and records from the source reporting databases and add them to the destination reporting database. After merging, the source database will be permanently deleted.

There are two major caveats to remember when merging:

  1. If a source database is being written to by active scripts, you may lose some records.
  2. If either a source or a destination database is being written to by a live script, the live script may be delayed while the merging is taking place.

Merges can be performed from the Management > Reports > Merge portion of the Watson™ Explorer Engine administration tool. To merge databases, select the source database from the list of available databases. Under the Merge into heading, choose the destination database from those listed in the pull-down menu. Click Merge.

After the merge, the source database will no longer exist, and the destination database will contain all of its entries. The source database will be recreated, if necessary, if an active script continues to write to it.

Note: Continually merging reporting databases can create huge database files that can be slow to process and merge. HUge database files may even exceed system capabilities such as available memory, causing merge failures. IBM suggests that you maintain no more than one year of merged reporting data online. You can also help avoid such merge problems by minimizing Watson Explorer Engine options, such as system reporting messages from distributed indexing, that can generate large amounts of logged data.