Skip to main content

Do Comments Throw Off Error Backtrace? No!


Just received this feedback on an Oracle Magazine article:
I’ve just started using DBMS_UTILITY.FORMAT_ERROR_BACKTRACE and it’s a great utility when the code contains no comments, but unless I’m missing something it’s not terribly useful with regard to pinpointing the exact line number when the code contains comments.
Now, I must confess that I am tempted to respond with such questions along these lines:
Did you try it out? That's the best way to learn!
But I am always looking for another reason to post on my blog and add to the LiveSQL repository. So that's what I am doing! :-)

The answer is quite straightforward:

Comments do not interfere with "pinpointing the exact line number" on which the error was raised.

But I bet you want proof, so let's get down to business.

I create a procedure with comments and a RAISE statement:

CREATE OR REPLACE PROCEDURE comments_throw_off_line# 
IS 
/* 
Here's my header 
 
Blah blah blah 
*/ 
BEGIN 
   DBMS_OUTPUT.put_line ('wow!'); 
   /* 
   And here's another comment because I really love 
   to fill my code with meaningless comments! 
   */ 
   RAISE PROGRAM_ERROR; /* This is line 14 */ 
EXCEPTION 
   WHEN OTHERS 
   THEN 
      DBMS_OUTPUT.put_line (DBMS_UTILITY.format_error_backtrace); 
END;

I run the procedure and see this output:

BEGIN 
   comments_throw_off_line#; 
END;

wow!
ORA-06512: at "COMMENTS_THROW_OFF_LINE#", line 14

So, there's your answer.

Next question? :-)

Comments

Popular posts from this blog

Running out of PGA memory with MULTISET ops? Watch out for DISTINCT!

A PL/SQL team inside Oracle made excellent use of nested tables and MULTISET operators in SQL, blending data in tables with procedurally-generated datasets (nested tables).  All was going well when they hit the dreaded: ORA-04030: out of process memory when trying to allocate 2032 bytes  They asked for my help.  The error occurred on this SELECT: SELECT  *    FROM header_tab trx    WHERE (generated_ntab1 SUBMULTISET OF trx.column_ntab)       AND ((trx.column_ntab MULTISET             EXCEPT DISTINCT generated_ntab2) IS EMPTY) The problem is clearly related to the use of those nested tables. Now, there was clearly sufficient PGA for the nested tables themselves. So the problem was in executing the MULTISET-related functionality. We talked for a bit about dropping the use of nested tables and instead doing everything in SQL, to avoid the PGA error. That would, however require lots of work, revamping algorithms, ensuring correctness, you know the score. Then my eyes snagge

How to Pick the Limit for BULK COLLECT

This question rolled into my In Box today: In the case of using the LIMIT clause of BULK COLLECT, how do we decide what value to use for the limit? First I give the quick answer, then I provide support for that answer Quick Answer Start with 100. That's the default (and only) setting for cursor FOR loop optimizations. It offers a sweet spot of improved performance over row-by-row and not-too-much PGA memory consumption. Test to see if that's fast enough (likely will be for many cases). If not, try higher values until you reach the performance level you need - and you are not consuming too much PGA memory.  Don't hard-code the limit value: make it a parameter to your subprogram or a constant in a package specification. Don't put anything in the collection you don't need. [from Giulio Dottorini] Remember: each session that runs this code will use that amount of memory. Background When you use BULK COLLECT, you retrieve more than row with each fetch,

Quick Guide to User-Defined Types in Oracle PL/SQL

A Twitter follower recently asked for more information on user-defined types in the PL/SQL language, and I figured the best way to answer is to offer up this blog post. PL/SQL is a strongly-typed language . Before you can work with a variable or constant, it must be declared with a type (yes, PL/SQL also supports lots of implicit conversions from one type to another, but still, everything must be declared with a type). PL/SQL offers a wide array of pre-defined data types , both in the language natively (such as VARCHAR2, PLS_INTEGER, BOOLEAN, etc.) and in a variety of supplied packages (e.g., the NUMBER_TABLE collection type in the DBMS_SQL package). Data types in PL/SQL can be scalars, such as strings and numbers, or composite (consisting of one or more scalars), such as record types, collection types and object types. You can't really declare your own "user-defined" scalars, though you can define subtypes  from those scalars, which can be very helpful from the p