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. Thanks for the post. Before I got used to the ambiguity, I kept looking into the docs. Having a single notation would be something to look forward to in both drizzle and mysql.

  2. Yes, this has annoyed me too, particularly early on. There’s a discussion right now about refactoring the configuration management for Drizzle into a plugin, hopefully fixing this can be included in that project 🙂

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