Candle-lite DB2 - Manual (Page 90)

Background about !DB/EXPLAIN for DB2
90 OMEGAMON II for DB2 User’s Guide: CUA Interface, Version 540
Background about !DB/EXPLAIN for DB2
This section provides an overview of the !DB/EXPLAIN functionality.
Functions provided by !DB/EXPLAIN for DB2
!DB/EXPLAIN provides a window into the operation of DB2. !DB/EXPLAIN offers
benefits for
■ extracting DB2 data
You can extract all or a portion of the data in the DB2 catalog according to the criteria
you specify. This flexible technology lets you
– Extract and combine data from multiple PLAN_TABLES.
– Access data when DB2 is not active.
– Avoid contention on the DB2 catalog.
– Retain histories of plan, package, and DBRM catalog data and their EXPLAINs.
■ DB2 database administration
You can use !DB/EXPLAIN functions to review and improve SQL. These features let
you
– Review application code and monitor specific SQL performance to understand
the access paths and their relative costs.
– Store historical information to perform impact analysis, historical analysis, and
perform “what-if” analysis.
– Manage DB2 objects by viewing statement use by package or plan and DBRMs
and BIND, REBIND, or FREE DB2 objects.
– Facilitate migration to a newer version of DB2.
■ application development
You can use !DB/EXPLAIN to analyze your design and improve SQL. These features
let you
– Analyze SQL code within an ISPF session to obtain access path information.
– Identify potential trouble spots.
– Execute SQL code within a batch facility and obtain a report.
– Obtain direct access from the IBM Query Management Facility (QMF) to different
types of queries.
– Tune your SQL code efficiently by suggesting more efficient alternative
techniques.