Uploaded image for project: 'MariaDB Server'
  1. MariaDB Server
  2. MDEV-107

Provide statistics counters for MRR

Details

    • Task
    • Status: Closed (View Workflow)
    • Major
    • Resolution: Fixed
    • 5.3.5
    • None
    • None

    Description

      We need statistics counters for MRR. In particular, we need

      • How many MRR scans were performed
      • How many key/rowid re-sort operations were made (Need separate counters for key and rowid ops).

      The first attempt at counters was:

      However, the names/semantics were deemed too complicated. Now, we need to come up with simpler definitions.

      == Proposal#1 ==

      • Handler_mrr_init - stays the same, counts rowid-ordered scans, key-ordered scans, and key-ordered rowid-ordered scans
      • Handler_mrr_rowid_ordered_passes - counts number of { sort rowids; do a rowid-ordered read sweep; }

        passes

      • Handler_mrr_key_ordered_passes - counts number of { sort keys; do a key-ordered read sweep; }

        passes

      == Proposal#2 ==
      Same as above but break Handler_mrr_init into three:

      • Handler_mrr_key_ordered
      • Handler_mrr_rowid_ordered
      • Handler_mrr_key_rowid_ordered

      == Decision ==

      On the last optimizer call, we've decided to go with these counters:

      Handler_mrr_init
      Handler_mrr_key_refills
      Handler_mrr_rowid_refills

      and the first fill is not counted as a "refill".

      Attachments

        Activity

          This is now coded, pushed, and documented.

          psergei Sergei Petrunia added a comment - This is now coded, pushed, and documented.

          Counters, as they are added, are inappropriate (Igor's feedback). We'll need to fix them.

          psergei Sergei Petrunia added a comment - Counters, as they are added, are inappropriate (Igor's feedback). We'll need to fix them.

          current counters:

          • Handler_mrr_init - counts how many MRR scans were performed
          • Handler_mrr_extra_rowid_sorts - counts rowid sort operations done in MRR scans, except the first scan in each operation
          • Handler_mrr_extra_key_sorts - counts key sort operations done in MRR scans, except the first scan in each operation
          psergei Sergei Petrunia added a comment - current counters: Handler_mrr_init - counts how many MRR scans were performed Handler_mrr_extra_rowid_sorts - counts rowid sort operations done in MRR scans, except the first scan in each operation Handler_mrr_extra_key_sorts - counts key sort operations done in MRR scans, except the first scan in each operation

          Push the patch with the new names.

          psergei Sergei Petrunia added a comment - Push the patch with the new names.

          New counters were pushed.

          psergei Sergei Petrunia added a comment - New counters were pushed.

          People

            psergei Sergei Petrunia
            psergei Sergei Petrunia
            Votes:
            0 Vote for this issue
            Watchers:
            0 Start watching this issue

            Dates

              Created:
              Updated:
              Resolved:

              Git Integration

                Error rendering 'com.xiplink.jira.git.jira_git_plugin:git-issue-webpanel'. Please contact your Jira administrators.