Does level 3 optimization change PL/Scope data? No!

I gave a webinar on April 6, 2017 for the Taste of Kscope17 series for ODTUG (odtug.com) on Change Impact Analysis with PL/Scope. Here are the slides from SlideShare. I will add a link to the video when it is available.

Impact Analysis with PL/Scope from Steven Feuerstein

After my presentation, this question came up: if you set the optimization level to 3 (inlining of subprogram code), will that change the PL/Scope data gathered? Interesting question.

Suppose your function body contains an assignment to variable x. Just that one place. But the function is called in ten places. Will PL/Scope find ten assignments to x or just one?

Just one, as you can see in this LiveSQL script. The identifier information is gathered before optimization. Which makes perfect sense. Post-optimized code is no longer PL/SQL code.

Here's the procedure I tested this one:

CREATE OR REPLACE PROCEDURE PLSCOPE_DEMO
IS
   PRAGMA INLINE (f1, 'YES');

   FUNCTION f1 (p NUMBER)
      RETURN PLS_INTEGER
   IS
   BEGIN
      RETURN p * 10;
   END;

   FUNCTION f2 (p BOOLEAN)
      RETURN PLS_INTEGER
   IS
   BEGIN
      RETURN CASE WHEN p THEN 10 ELSE 100 END;
   END;

   FUNCTION f3 (p PLS_INTEGER)
      RETURN PLS_INTEGER
   IS
   BEGIN
      RETURN p * 10;
   END;
BEGIN
   DBMS_OUTPUT.put_line (f1 (1));
   
   PRAGMA INLINE (f2, 'YES');
   DBMS_OUTPUT.put_line (f2 (TRUE) + f2 (FALSE));

   PRAGMA INLINE (f3, 'NO');
   DBMS_OUTPUT.put_line (f3 (55));
END;

Here's the query I used to get my identifier information back out.

  SELECT i.signature ||'-'|| s.line ||'-'|| s.text text 
    FROM    user_identifiers i 
         JOIN 
            user_source s 
         ON (    s.name = i.object_name 
             AND s.TYPE = i.object_type 
             AND s.line = i.line) 
   WHERE object_name = 'PLSCOPE_DEMO'  
ORDER BY s.line

And the output is the same regardless of the optimization level:

7189BE581AF770C7FA9F660333721E03-1-PROCEDURE PLSCOPE_DEMO
7189BE581AF770C7FA9F660333721E03-1-PROCEDURE PLSCOPE_DEMO
47BFC756469F1D97B6C84EF73A9C5D48-5-   FUNCTION f1 (p NUMBER)
785705602C9312732B24D9A341360ACF-5-   FUNCTION f1 (p NUMBER)
C762ED3C314ABB3D7257031401DD1583-5-   FUNCTION f1 (p NUMBER)
C762ED3C314ABB3D7257031401DD1583-5-   FUNCTION f1 (p NUMBER)
2C17DB6428F739B212C1E11EED057D63-6-      RETURN PLS_INTEGER
785705602C9312732B24D9A341360ACF-9-      RETURN p * 10;
1B5895A65C6952FDD192221BFC45A132-12-   FUNCTION f2 (p BOOLEAN)
C0BA9F319D1E759AD02A3C7138D62232-12-   FUNCTION f2 (p BOOLEAN)
EE1C5F13825B7DF0BF06D82DE633992E-12-   FUNCTION f2 (p BOOLEAN)
1B5895A65C6952FDD192221BFC45A132-12-   FUNCTION f2 (p BOOLEAN)
2C17DB6428F739B212C1E11EED057D63-13-      RETURN PLS_INTEGER
C0BA9F319D1E759AD02A3C7138D62232-16-      RETURN CASE WHEN p THEN 10 ELSE 100 END;
335958BDCA260D5E550A47F8194048DC-19-   FUNCTION f3 (p PLS_INTEGER)
205AC954A1ADD2BC3DC6A112A2081ADA-19-   FUNCTION f3 (p PLS_INTEGER)
2C17DB6428F739B212C1E11EED057D63-19-   FUNCTION f3 (p PLS_INTEGER)
335958BDCA260D5E550A47F8194048DC-19-   FUNCTION f3 (p PLS_INTEGER)
2C17DB6428F739B212C1E11EED057D63-20-      RETURN PLS_INTEGER
205AC954A1ADD2BC3DC6A112A2081ADA-23-      RETURN p * 10;
C762ED3C314ABB3D7257031401DD1583-26-   DBMS_OUTPUT.put_line (f1 (1));
1B5895A65C6952FDD192221BFC45A132-29-   DBMS_OUTPUT.put_line (f2 (TRUE) + f2 (FALSE));
1B5895A65C6952FDD192221BFC45A132-29-   DBMS_OUTPUT.put_line (f2 (TRUE) + f2 (FALSE));
335958BDCA260D5E550A47F8194048DC-32-   DBMS_OUTPUT.put_line (f3 (55));

For more information about PL/Scope:

• Full set of LiveSQL PL/Scope scripts
• Other blog posts by yours truly on PL/Scope
• PL/Scope documentation
• Powerful Impact Analysis: Oracle Magazine article on PL/Scope's ability to analyze SQL statements in your PL/SQL code.

For more information about Inlining:

• A PL/SQL Inlining Primer