![]() But this is not necessarily the same as the plan that was used at the time the given statement was actually executed. For best results, use the Oracle Trace or SQL trace facility and TKPROF to examine performance information on individual SQL statements.Īttention: EXPLAIN PLAN tells you the execution plan the optimizer would choose if it were to produce an execution plan for a SQL statement at the current time, with the current set of initialization and session parameters. Instead, you should examine the statement's actual resource consumption. It is not necessarily useful to subjectively evaluate the plan for a statement, and decide to tune it based only on the execution plan. The index might be very inefficient! Use EXPLAIN PLAN to determine the access plan, and to test modifications to improve the performance. For example, just because EXPLAIN PLAN indicates that a statement will use an index does not mean that the statement will run quickly. By examining the execution plan, you can see exactly how Oracle executes your SQL statement.ĮXPLAIN PLAN results alone cannot tell you which statements will perform well, and which badly. A statement's execution plan is the sequence of operations that Oracle performs to execute the statement. ![]() The EXPLAIN PLAN command displays the execution plan chosen by the Oracle optimizer for SELECT, UPDATE, INSERT, and DELETE statements. See Also: For the syntax of the EXPLAIN PLAN command, see the Oracle7 Server SQL Reference. This chapter shows how to use the SQL command EXPLAIN PLAN. The EXPLAIN PLAN Command Oracle7 Tuning, release 7.3.3
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