pt-config-diff does not see difference

Description

Notice the change of 'innodb_autoextend_increment' from 64 to 128 within a running mysql server. pt-config-diff, comparing the global my.cnf to the running config does not see the change.

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Lalit Choudhary July 6, 2020 at 2:39 PM

I do not think this as a bug since we are comparing  option file (e.g. my.cnf) to an active config  in such case as per documentation "Only values of the variables present in both configs are compared."

https://www.percona.com/doc/percona-toolkit/LATEST/pt-config-diff.html#description

Only variables that all CONFIG sources have are compared because if a variable is not present then we cannot know or safely guess its value. For example, if you compare an option file (e.g. my.cnf) to an active config (i.e. SHOW VARIABLES from a DSN CONFIG), the option file will probably only have a few variables, whereas the active config has every variable. Only values of the variables present in both configs are compared.

Lalit Choudhary July 6, 2020 at 2:30 PM
Edited

Issue reproduciable when we do the comparison for mysql config file and running global ( “active config”)variables.

 Test 1:
my.sandbox.cnf

 

 

Test2: 
my.sandbox.cnf

Lalit Choudhary July 6, 2020 at 2:01 PM
Edited

Hi Matthew, 

Thank you for the report. 

 

Not a Bug

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Created June 16, 2020 at 9:42 PM
Updated July 6, 2020 at 2:40 PM
Resolved July 6, 2020 at 2:40 PM