Ensure that these prerequisites are met before using EXPLAIN
snapshots to find and fix changes in multiple access plans or compare
multiple access plans.
You use EXPLAIN snapshots when finding and fixing changes
in these situations:
- After the addition, removal, or modification of SQL statements
in an application
- After release migration or the application of maintenance fixes
- After changes to database structure or authorizations
- After deploying an application from a test system to a production
system
You also use EXPLAIN snapshots when comparing access plans
in these situations:
- After running the RUNSTATS utility
- After generating index recommendations with the Workload Index
Advisor
- After testing candidate indexes virtually
- After twice testing candidate indexes virtually
An EXPLAIN snapshot in InfoSphere® Optim™ Query Workload Tuner is a set of EXPLAIN
information that is collected at a point in time.
- If the SQL statements run on DB2® for z/OS®:
- In the Data Source Explorer, connect to a DB2 for z/OS subsystem
that is configured for query workload tuning and where a license for IBM® InfoSphere Optim Query
Workload Tuner is active.
- You must have the following privilege on these tables:
- SELECT, INSERT, UPDATE, and DELETE privileges on the following
tables: DB2OSC.AOC_WAPC_SESSIONS, DB2OSC.AOC_WAPC_RS and DB2OSC.AOC_WAPC_EX
- SELECT privilege on the following tables: DB2OSC.DSN_WCC_EV_HISTORY,
DB2OSC.DSN_WCC_EP_HISTORY, DB2OSC.DSN_WCC_STMT_INSTS, DB2OSC.DSN_STATEMNT_TABLE,
DB2OSC.DSN_WCC_STMT_RUNTM, and DB2OSC.DSN_WCC_STMT_TEXTS
- SELECT privilege on the EXPLAIN tables (PLAN_TABLE and DSN_STATEMNT_TABLE)
under schema DB2OSC
- If the SQL statements run on DB2 for Linux, UNIX, and Windows:
-