Publishing Reports to the Web - Downloads - Oracle

Note: For large queries, it is imperative to do one of the following:
■ Activate the cost-based optimizer and gather statistics by using
the DBMS_STATS package, the COMPUTER STATISTICS
option, or the ANALYZE command.
■ Optimize all SQL following the rules laid out by the rule-based
optimizer.
The Oracle Application Server documentation provides more information on the
database optimizer’s functionality.
Methodology
20.1.1.3 PL/SQL
Use the ORA_PROF built-in package to tune your report’s PL/SQL program units. The
procedures, functions, and exceptions in the ORA_PROF built-in package allow you to
track the amount of time that pieces of your code takes to run.
Example
PROCEDURE timed_proc (test VARCHAR2) IS
i PLS_INTEGER;
BEGIN
ORA_PROF.CREATE_TIMER('loop2');
ORA_PROF.START_TIMER('loop2');
ColorBand_Program_Unit;
ORA_PROF.STOP_TIMER('loop2');
TEXT_IO.PUTF('Loop executed in %s seconds.\n',
ORA_PROF.ELAPSED_TIME('loop2'));
ORA_PROF.DESTROY_TIMER('loop2');
END;
This procedure creates a timer, starts it, runs a subprogram, stops the timer, and
displays the time it took to run. It destroys the timer when finished.
Refer to Reports Builder online help for more information on the ORA_PROF built-in
package.
Implement PL/SQL program units performing a significant amount of database
operations as stored database procedures. Stored procedures run directly on the Oracle
database and perform operations more quickly than local PL/SQL program units.
Local PL/SQL program units use the Reports Builder’s PL/SQL parser, then the
database’s SQL parser, and also include a network trip.
PL/SQL program units that do not perform any database operations should be coded
as locally as possible using the Program Units node in the Object Navigator. Localizing
the PL/ SQL program unit has a performance advantage over executing PL/SQL from
an external PL/SQL library. Use external PL/SQL libraries only when the benefits of
code sharing can be utilized.
The SRW.DO_SQL() built-in procedure should be used as sparingly as possible. Each
call to the SRW.DO_SQL() built-in procedure necessitates parsing and binding the
command and opening a new cursor like a normal query. Unlike a normal query, this
operation will occur each time the object owning the SRW.DO_SQL() built-in
procedure fires.
For example, a PL/SQL block in a formula column calls the SRW.DO_SQL() built-in
procedure and the data model group returns 100 records. In this case, the parse/ bind/
create cursor operation occurs 100 times. Therefore, use the SRW.DO_SQL() built-in
Tuning Oracle Reports 20-7