Uploaded image for project: 'Percona XtraBackup'
  1. Percona XtraBackup
  2. PXB-1668

Off by one error for --throttle option

    XMLWordPrintable

    Details

    • Type: Bug
    • Status: Pending Release
    • Priority: Medium
    • Resolution: Done
    • Affects Version/s: None
    • Fix Version/s: 2.4.13, 2.3.NEXT, 8.0.4
    • Component/s: None
    • Labels:
      None

      Description

      As stated in https://jira.percona.com/browse/PXB-1631 with --throttle option we should be limiting the disk transfer to number of specified 10MB units per second.

      However, effectively the limit is N+1 of units per second due to the code issue:

      void
      xtrabackup_io_throttling(void)
      {
      	if (xtrabackup_throttle && (io_ticket--) < 0) {
      		os_event_reset(wait_throttle);
      		os_event_wait(wait_throttle);
      	}
      }
      

      I can confirm in my tests that using --throttle=1 option results in disk reads of ~20MB/s, --throttle=2 gives ~30MB/s, etc.

        Attachments

          Activity

            People

            • Assignee:
              sergei.glushchenko Sergei Glushchenko
              Reporter:
              przemyslaw.malkowski@percona.com Przemyslaw Malkowski
            • Votes:
              0 Vote for this issue
              Watchers:
              1 Start watching this issue

              Dates

              • Created:
                Updated:
                Resolved:

                Time Tracking

                Estimated:
                Original Estimate - Not Specified
                Not Specified
                Remaining:
                Remaining Estimate - 0 minutes
                0m
                Logged:
                Time Spent - 3 hours
                3h