7.1 DBMS_PROFILER: Providing Code Profiling | Oracle PL/SQL Programming: Guide to Oracle8i Features


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	Oracle PL/SQL Programming Guide to Oracle 8 i Features By Steven Feuerstein
	Table of Contents

	Chapter 7. New and Enhanced Built-in Packages in Oracle8i

7.1 DBMS_PROFILER: Providing Code Profiling

In Oracle8 i , Oracle adds a new package, DBMS_PROFILER, to facilitate performance and code coverage analysis of your PL/SQL application. Use this package to define one or more runs of your code and collect a wide range of information about the code that is executed in that run.

The API for this package is very simple. You start the profiler, run your code, and stop the profiler. The PL/SQL engine will have populated up to three different tables with the performance and code coverage information. You can then use SQLeither your own queries or one of the reports offered by Oracleto examine the results of the run.

7.1.1 DBMS_PROFILER Programs

The DBMS_PROFILER package contains the two functions listed in Table 7.2.

Table 7.2. DBMS_PROFILER Programs

Program	Description
DBMS_PROFILER.START_PROFILER function	Starts profiling in the current connection. You can provide an optional string to give a name to the profiling session.
DBMS_PROFILER.STOP_PROFILER function	Ends profiling in the current connection.

7.1.2 Installing DBMS_PROFILER

The DBMS_PROFILER package may not have been installed automatically for you when the database was set up. In this case, you will need to install the package specification and body. After that, you will want to create profiler tables and packages to help you analyze the output (stored in the profiler tables) more effectively.

Table 7.3 shows all of the files related to DBMS_PROFILER that you will probably want to run. You will find most of these files on Windows NT in one of the following directories (the exceptions are the demo files profrep.sql and profsum.sql) , depending on how you installed the database:

\Oracle\Ora81\Rdbms\Admin\

\Ora81\Rdbms\Admin\

Regardless of the higher-level directory structure, these files will always be found in the Rdbms\Admin subdirectory under the Oracle 8.1 home directory.

Table 7.3. DBMS_PROFILER Files

File	Description
dbmspbp.sql	DBMS_PROFILER package specification; this package should be created automatically when you install the Oracle8 i database. You may want to examine this file to read the documentation.
prvtpbp.plb	DBMS_PROFILER package body/library definition. This is a wrapped file and should be executed automatically when you install the Oracle8 i database.
profload.sql	Orchestrates the loading of dbmspbp.sql and prvtpbp.plb. This script must be run under a DBA account.
proftab.sql	Script to create the profiling tables. When you profile a program, data is written to one or more of these tables: plsql_profiler_runs plsql_profiler_units plsql_profiler_data
profrep.sql	Creates a set of views and a reporting package named prof_report_utilities that offers an API to more easily extract reports from the profiling tables. Found under \plsql\demo .
profsum.sql	A set of ad hoc queries and calls to programs in the prof_report_utilities package. Don't run the whole file unless you have a small volume of data in your profiling tables. Instead, go through the file and extract those queries that you want to run. Found under \plsql\demo .

You can define the profiler tables in each individual schema developers want to profile. You can also define the profiler tables in a central schema, to be shared among multiple developers. In this case, you need to grant full access to all of the tables and to the sequence that defines the run number. You will also need to create public synonyms.

The profiler will not profile a PL/SQL block unless the current user has CREATE access on the block.

7.1.3 DBMS_PROFILER Example

It's certainly easy enough to use the PL/SQL profiler. Here's an example of the code you would execute:

 /* Filename on companion disk: profiler.sql */ BEGIN    DBMS_OUTPUT.PUT_LINE (       DBMS_PROFILER.START_PROFILER (          'showemps '            TO_CHAR (SYSDATE, 'YYYYMMDD HH24:MI:SS')          )       );    showemps;    DBMS_OUTPUT.PUT_LINE (       DBMS_PROFILER.STOP_PROFILER); END; /

If you do not pass an argument to START_PROFILER, then the "name" of the profile run is SYSDATE. In the example just given, I want to record both the name of the program I am running and the date-time stamp so that I can distinguish this run from others for the same program.

7.1.4 Profiler Return Codes

Both START_PROFILER and END_PROFILER are functions that return a status code. A value of 0 means that the program was called successfully. A nonzero return code indicates a problem, and may be one of the values listed in Table 7.4.

Table 7.4. DBMS_PROFILER Return Codes

Database Constant	Value	Description
DBMS_PROFILER.SUCCESS		No problem!
DBMS_PROFILER.ERROR_PARM	1	A subprogram was called with an incorrect parameter.
DBMS_PROFILER.ERROR_IO	2	An attempt to flush profile data to the tables failed. Make sure the tables are present and accessible and have sufficient space for the inserts .
DBMS_PROFILER.ERROR_VERSION	-1	The engine has detected a mismatch between the profiler package and the database version. The only possible recovery is to install the correct version of the package.

Consider yourself warned : unless you are running a very simple application, the profiler will write thousands of rows of data to its tables. To make it easier for you to manage all this information, I have created the following scripts, located on the companion disk:

proftrunc.sql: Truncates all three profiling tables
profdel.sql: Deletes all rows from the three profiling tables for the specified run number


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