Uploaded image for project: 'Documentation'
  1. Documentation
  2. DOCS-3177

The per-database RW-lock is not yielded when searching an index

    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Minor - P4
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: v1.3.7
    • Component/s: manual
    • Labels:
      None
    • # Replies:
      2
    • Last comment by Customer:
      true
    • Actual Time:
      8

      Description

      The docs at http://smalldatum.blogspot.com/2014/04/mongodb-tokumx-and-innodb-for-disk-io_15.html were not clear to me on three issues:
      1) the per-db RW-lock is not yielded from page faults while searching an index.
      2) this is only done for "predicted page faults", not real page faults. And I am not suggesting that it should be done on real page faults.
      3) a pending write lock request prevents new read requests when the per-db RW-lock is currently locked in read-mode. The FAQ states that W has precedence over read but I think that you should also mention this behavior.

      See http://smalldatum.blogspot.com/2014/04/mongodb-tokumx-and-innodb-for-disk-io_15.html for performance results and a brief description of the code.

        Activity

        Hide
        mdcallag Mark Callaghan added a comment -
        Show
        mdcallag Mark Callaghan added a comment - First link should be http://docs.mongodb.org/manual/faq/concurrency/
        Hide
        xgen-internal-githook Githook User added a comment -

        Author:

        {u'username': u'tychoish', u'name': u'Sam Kleinman', u'email': u'samk@10gen.com'}

        Message: DOCS-3177 concurency FAQ updates
        Branch: master
        https://github.com/mongodb/docs/commit/e06b57ff6cca21fda63bd58429e035d3c7b9c065

        Show
        xgen-internal-githook Githook User added a comment - Author: {u'username': u'tychoish', u'name': u'Sam Kleinman', u'email': u'samk@10gen.com'} Message: DOCS-3177 concurency FAQ updates Branch: master https://github.com/mongodb/docs/commit/e06b57ff6cca21fda63bd58429e035d3c7b9c065

          People

          • Votes:
            0 Vote for this issue
            Watchers:
            3 Start watching this issue

            Dates

            • Created:
              Updated:
              Resolved:
              Days since reply:
              3 years ago
              Date of 1st Reply: