Xaprb

It’s been ages since we’ve had an update to innotop, or at least, it’s been a while since the changes were bundled up and released officially. Barring any bug reports against the trunk code, I’m about ready to release more than a year’s worth of improvements to it:

   Changes:
   * Don't re-fetch SHOW VARIABLES every iteration; it's too slow on many hosts.
   * Add a filter to remove EVENT threads in SHOW PROCESSLIST (issue 32).
   * Add a timestamp to output in -n mode, when -t is specified (issue 37).
   * Add a new U mode, for Percona/MariaDB USER_STATISTICS enhancements (issue 39).
   * Add support for millisecond query time in Percona Server (issue 39).
   * Display a summary of queries executed in Query List mode (issue 26).

   Bugs fixed:
   * Hostname parsing wasn't standards compliant (issue 30).
   * MKDEBUG didn't work on some Perl versions (issue 22).
   * Don't try to get InnoDB status if have_innodb != YES (issue 33).
   * Status text from the InnoDB plugin wasn't parsed correctly (issue 36).
   * Transaction ID from the InnoDB plugin wasn't subtracted correctly (issue 38).
   * Switching modes and pressing ? for help caused a crash (issue 40).

After a long time working mostly on Maatkit and neglecting innotop, Aaron Racine has stepped forward to take over the development. I moved it off Sourceforge (for the same reasons I moved Maatkit) and onto Google Code. Aaron has set up mailing lists and so on, and there is a discussion about which features to add and change. Your input is welcomed on the mailing lists!

Rob Young has posted a few blog entries lately on the MySQL Enterprise monitoring software. His latest post claims that agent-based monitoring is equivalent to extensibility (MySQL Enterprise Monitor: Agent = Extensibility).

I think this is conflating two completely distinct properties of a monitoring solution. Cacti is extremely extensible, with a plugin-based architecture and templates and all kinds of other goodies; yet it is not agent-based (actually it lets you choose — now that’s extensibility). innotop is not agent-based, and it’s extremely extensible too. Basically everything inside innotop is a lookup table of anonymous subroutines and data structures that you can tweak pretty much infinitely with plugins and configuration files that get merged into the running code dynamically. Extensibility is completely orthogonal to whether the architecture is agent-based. What about WordPress? It’s ridiculously extensible and it has nothing to do with agents.

So now that we’ve clarified that, what can we say about agent-based or agentless architectures? Which is better?