Uploaded image for project: 'Percona XtraBackup'
  1. Percona XtraBackup
  2. PXB-349

LP #1095249: Built-in compression does inefficient I/O

    Details

    • Type: Bug
    • Status: Done
    • Priority: High
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: None
    • Labels:

      Description

      **Reported in Launchpad by Alexey Kopytov last update 13-01-2013 00:07:43

      --compress does 4 unbuffered I/O operations per every 64K block of uncompressed data:

      • it first writes an 8-byte compressed block header
      • then it writes an 8-byte file offset
      • then it writes a 4-byte checksum
      • finally the compressed contents of the original 64K block is written

      Each write is followed by a posix_fadvise(FADV_DONTNEED) call, which is of course very inefficient.

      The fix is to buffer the output compressed stream.

        Smart Checklist

          Attachments

            Activity

              People

              • Assignee:
                Unassigned
                Reporter:
                lpjirasync lpjirasync (Inactive)
              • Votes:
                0 Vote for this issue
                Watchers:
                1 Start watching this issue

                Dates

                • Created:
                  Updated:
                  Resolved: