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Locking Data Explicitly

The V$SQL_PLAN_STATISTICS_ALL view contains memory usage statistics for row sources that use SQL memory (sort or hash-join). This view concatenates information in V$SQL_PLAN with execution statistics from

V$SQL_PLAN_STATISTICS and V$SQL_WORKAREA.

See Also: Oracle Database Reference for details on these views

Closing Cursors

Closing a cursor means that the information currently in the associated private area is lost and its memory is deallocated. Once a cursor is opened, it is not closed until one of the following events occurs:

The user program terminates its connection to the server.

If the user program is an OCI program or precompiler application, then it explicitly closes any open cursor during the execution of that program. (However, when this program terminates, any cursors remaining open are implicitly closed.)

Cancelling Cursors

Cancelling a cursor frees resources from the current fetch.The information currently in the associated private area is lost but the cursor remains open, parsed, and associated with its bind variables.

Note: You cannot cancel cursors using Pro*C or PL/SQL.

See Also: Oracle Call Interface Programmer's Guide for more information about cancelling cursors

Locking Data Explicitly

Oracle Database always performs necessary locking to ensure data concurrency, integrity, and statement-level read consistency. You can override these default locking mechanisms. For example, you might want to override the default locking of Oracle Database if:

You want transaction-level read consistency or "repeatable reads"—where transactions query a consistent set of data for the duration of the transaction, knowing that the data has not been changed by any other transactions. This level of consistency can be achieved by using explicit locking, read-only

5-10 Oracle Database Application Developer's Guide - Fundamentals

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