Variables ambiguities in names and values

Writing up some scripts, I see more and more ambiguities with regard to global variables.

For one thing, the names ambiguity between the hyphen (‘-‘) and the underscore (‘_’). So wait_timeout and wait-timeout are the same variable.

But just check out the many levels of inconsistency:

  • Command line arguments (e.g. run mysqld with option variables) use the hyphen convention
  • mysql –verbose –help shows the hyphen convention
  • SHOW GLOBAL VARIABLES uses the underscore convention
  • The MySQL supplied sample configuration files use both conventions interchangeably

Enough? Not quite: there are ambiguities in values, as well. For example, you may set query_cache_type to 1 or ON. These are equivalent. That’s very friendly. However:

  • mysql –verbose –help will show “query_cache_type 1
  • SHOW GLOBAL VARIABLES will show “query_cache_type ON

We also have:

  • 1 <==> YES
  • OFF <==> FALSE
  • ON <==> TRUE

Time to decide. Ambiguities are evil. They make for a difficult parsing/analysis/comparison/validation work. Will anyone pick the glove?

PS – Drizzle falk – isn’t this the kind of stuff you’re happy to drop?

6 thoughts on “Variables ambiguities in names and values

  1. The programming public is Boolean-challenged. I get so irritated every time I see (in any of several languages)
    if () x = TRUE else x = FALSE;

    The equivalence of 0/false/off and 1/true/on will be hard to ‘teach’, regardless of which way you go.

    I do agree that consistency would be nice. Fortunately, MySQL is usually forgiving.

    Another frustration: The flags that are done by there presence/absence, perhaps including
    log-slave-updates
    skip-external-locking

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.