Webdev:Meetings:2008-12-23

• laura
  • SUMO release OMG.
• lars
  • finished initial coding of perfomatic's new collector w/ unit tests
  • wrote a quickie for chofmann to get urls from uuids
• rdoherty
  • Community Store push last week
  • Rewriting Graph server javascript code
• lorchard
  • LizardFeeder launch attempt, still pending
  • AMO Bandwagon feed working, lessons learned:
    • Problem:
      • Models yield truckloads of deeply nested arrays, even with unbindFully()
      • Sanitizing is heavily recursive, slow, and appears to tickle PHP-level memory leaks with is_array() and other functions.
      • This combination lead to an inability to build the feed in under 90 seconds and 64mb of RAM.
        • The function was called 1M times before optimization, and 50K after, still leaked memory like a sieve (12MB before first call, 64MB after last).
        • Since our php.ini limits to 30 seconds and 16MB, this is fail. (Never mind that it's insane on the face of it.)
    • Solution:
      • Never feed Model result arrays straight into sanitizing.
      • Build an intermediate array, as flat as possible, with only the minimal amount of data necessary for the View.
      • This reduces both the recursion and work sanitizing needs do to in general.
    • Bonus:
      • Learned all about using XDebug with 650MB cachegrind files, which don't work in webgrind and require KCachegrind or WinCachegrind to view.
      • Turning on function tracing (separate from profiling) offers a peek at memory usage from call to call.
      • Even with memcache available, CakePHP adds 100000's of function calls of overhead, for what it's worth.