International Business Machines Corporation
Updating of in-memory synopsis metadata for inserts in database table

Abstract:

In updating a synopsis table of a database system, a database management unit performs a transaction to insert row(s) in a section of the base table and determines whether a synopsis entry for the section is stored in the memory. If stored in the memory, the in-memory synopsis entry is retrieved and metadata values in the in-memory synopsis entry are updated with data from the row(s) to be inserted. If not stored in the memory, the in-memory synopsis entry is generated and the metadata values in the in-memory synopsis entry are updated with data from the row(s). The insert transaction is then committed. Synopsis entry on-disk updates are thus avoided, significantly reducing the cost of updating the synopsis entries from the insert transaction. This yields enhanced performance especially for inserts of a small number of rows, while the benefits of synopsis entries are still available.