Chapter 25. Using EXPLAIN
In This Chapter
• Access Paths and the PLAN_TABLE
• Cost Estimates and the DSN_STATEMNT_TABLE
• Function Resolution and the DSN_FUNCTION_TABLE
You can use the EXPLAIN
feature to detail the access paths chosen by the DB2 optimizer for SQL statements. EXPLAIN
should be a key component of your performance monitoring strategy. The information provided by EXPLAIN
is invaluable for determining the following:
• The work DB2 does “behind the scenes” to satisfy a single SQL statement
• Whether DB2 uses available indexes and, if indexes are used, how DB2 uses them
• Whether ...
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