Execution Plans

Watch Long-Running SQL in Real Time with V$SQL_MONITOR Purpose An AWR report describes what happened over the last hour. A SQL trace file describes what happened after the statement has already finished writing it. V$SQL_MONITOR answers a different question: what is running right now, and how far along is it. …

Get the Actual Execution Plan with DBMS_XPLAN.DISPLAY_CURSOR Purpose EXPLAIN PLAN never runs the statement it describes. It asks the optimizer what it would do, based on statistics and cardinality estimates, and prints that guess — which is exactly why a query that looks fine in EXPLAIN PLAN can still run slow in …