Script is failing on MySQL 5.6.10(AWS Aurora)

[kirtangajjar]

Getting following error when running it on Mysql 5.6 (AWS Aurora) -

 >>  MySQLTuner 1.7.15 - Major Hayden <major@mhtx.net>

Use of uninitialized value in division (/) at mysqltuner.pl line 2657 (#1)
    (W uninitialized) An undefined value was used as if it were already
    defined.  It was interpreted as a "" or a 0, but maybe it was a mistake.
    To suppress this warning assign a defined value to your variables.

    To help you figure out what was undefined, perl will try to tell you
    the name of the variable (if any) that was undefined.  In some cases
    it cannot do this, so it also tells you what operation you used the
    undefined value in.  Note, however, that perl optimizes your program
    and the operation displayed in the warning may not necessarily appear
    literally in your program.  For example, "that $foo" is usually
    optimized into "that " . $foo, and the warning will refer to the
    concatenation (.) operator, even though there is no . in
    your program.

Illegal division by zero at mysqltuner.pl line 2657 (#2)
    (F) You tried to divide a number by 0.  Either something was wrong in
    your logic, or you need to put a conditional in to guard against
    meaningless input.

Uncaught exception from user code:
	Illegal division by zero at mysqltuner.pl line 2657.
	main::calculations() called at mysqltuner.pl line 6307

[jmrenouard]

Hi @kirtangajjar

I hav no AWS env. to perform tests.

Help welcomes !

[kirtangajjar]

@jmrenouard I debugged the issue and found that the error is occuring here - https://github.com/major/MySQLTuner-perl/blob/master/mysqltuner.pl#L2657

At that line, $myvar{'innodb_buffer_pool_size'} is not initialized. That is because running SHOW VARIABLES in AWS RDS does not return innodb_buffer_pool_size(maybe because it's dynamic). To fix this problem, we just have to ensure that $myvar{'innodb_buffer_pool_size'} and $mycalc{'innodb_log_size_pct'} are initialized

I did make a hackish attempt to solve this problem with below code and it seems to work, but I'm not sure if it might have other unintended consequences.

    # InnoDB
    if ( $myvar{'have_innodb'} eq "YES" && defined $myvar{'innodb_buffer_pool_size'} ) {
        $mycalc{'innodb_log_size_pct'} =
          ( $myvar{'innodb_log_file_size'} *
              $myvar{'innodb_log_files_in_group'} * 100 /
              $myvar{'innodb_buffer_pool_size'} );
    }

    if( !defined $myvar{'innodb_buffer_pool_size'}) {
      $mycalc{'innodb_log_size_pct'} = 0;
      $myvar{'innodb_buffer_pool_size'} = 0;
    }

If this looks fine to you, I can raise a PR for it.

[jmrenouard]

Hi, fixed in MySQLTuner 1.7.18

[dhsathiya]

@jmrenouard Seems lilke same error with some other variable.
Getting following error when running it on Mysql 5.6 (AWS Aurora) -

 >>  MySQLTuner 1.7.19 - Major Hayden <major@mhtx.net>
Use of uninitialized value in division (/) at mysqltuner.pl line 2706 (#1)
    (W uninitialized) An undefined value was used as if it were already
    defined.  It was interpreted as a "" or a 0, but maybe it was a mistake.
    To suppress this warning assign a defined value to your variables.
    
    To help you figure out what was undefined, perl will try to tell you
    the name of the variable (if any) that was undefined.  In some cases
    it cannot do this, so it also tells you what operation you used the
    undefined value in.  Note, however, that perl optimizes your program
    and the operation displayed in the warning may not necessarily appear
    literally in your program.  For example, "that $foo" is usually
    optimized into "that " . $foo, and the warning will refer to the
    concatenation (.) operator, even though there is no . in
    your program.
    
Illegal division by zero at mysqltuner.pl line 2706 (#2)
    (F) You tried to divide a number by 0.  Either something was wrong in
    your logic, or you need to put a conditional in to guard against
    meaningless input.
    
Uncaught exception from user code:
        Illegal division by zero at mysqltuner.pl line 2706.
        main::calculations() called at mysqltuner.pl line 6376

[jmrenouard]

If someone want to handle that.

[RafalLukawiecki]

Just tried on Aurora and the error is still present, though lists line 2707. I am new to this script. Also getting "274 CVE(s) found"—I suspect it does not get the version string correctly from Aurora.

[OliverBailey]

	line 2 (#1)
    (W uninitialized) An undefined value was used as if it were already
    defined.  It was interpreted as a "" or a 0, but maybe it was a mistake.
    To suppress this warning assign a defined value to your variables.
    
    To help you figure out what was undefined, perl will try to tell you
    the name of the variable (if any) that was undefined.  In some cases
    it cannot do this, so it also tells you what operation you used the
    undefined value in.  Note, however, that perl optimizes your program
    and the operation displayed in the warning may not necessarily appear
    literally in your program.  For example, "that $foo" is usually
    optimized into "that " . $foo, and the warning will refer to the
    concatenation (.) operator, even though there is no . in
    your program.
    
Illegal division by zero at mysqltuner.pl line 2707, <STDIN> line 2 (#2)
    (F) You tried to divide a number by 0.  Either something was wrong in
    your logic, or you need to put a conditional in to guard against
    meaningless input.
    
Uncaught exception from user code:
	Illegal division by zero at mysqltuner.pl line 2707, <STDIN> line 2.
	main::calculations() called at mysqltuner.pl line 6377

Aye, same thing here