Bug #20228 engine_condition_pushdown = on in my.cnf should work. currently must be 1
Submitted: 2 Jun 2006 15:04 Modified: 2 Jun 2006 15:16
Reporter: Jonathan Miller Email Updates:
Status: Verified Impact on me:
None 
Category:MySQL Server: General Severity:S4 (Feature request)
Version:5.1.12/5.0BK OS:Linux (Linux 32 Bit OS)
Assigned to: CPU Architecture:Any

[2 Jun 2006 15:04] Jonathan Miller
Description:
You can set through SQL either engine_condition_pushdown = on or engine_condition_pushdown = 1, but in the my.cnf you must use engine_condition_pushdown = 1 to get it on at startup. 

Customers should be able to use either "on" or "1" in the my.cnf for readability 

How to repeat:
Try in the my.cnf
engine_condition_pushdown = on
restart and look at variables, then switch to 
engine_condition_pushdown = 1
restart and look at variables

Suggested fix:
Customers should be able to use either "on" or "1" in the my.cnf for readability
[2 Jun 2006 15:16] MySQL Verification Team
Thank you for the bug report. Verified as described.
[2 Jun 2006 16:09] Paul DuBois
This behavior is not specific to this option. It occurs in general.

http://dev.mysql.com/doc/refman/5.0/en/using-system-variables.html:

Note: Some system variables can be enabled with the SET statement 
by setting them to ON or 1, or disabled by setting them to OFF or
0. However, to set such a variable on the command line or in an
option file, you must set it to 1 or 0; setting it to ON or OFF
will not work. For example, on the command line, --delay_key_write=1
works but --delay_key_write=ON does not.

So this might be a feature request, but as it is documented behavior,
it is not a bug.