Uploaded image for project: 'WiredTiger'
  1. WiredTiger
  2. WT-6251

Fix splits to reduce the size of index files

    XMLWordPrintableJSON

Details

    • Improvement
    • Status: Closed
    • Major - P3
    • Resolution: Fixed
    • None
    • WT10.0.0, 4.4.0-rc7, 4.7.0
    • None
    • None
    • 8
    • Storage - Ra 2020-06-01

    Description

      WT-6082 worked towards storing the validity window on the data files only when really needed. The driving workload behind that improvement was WiredTiger's simple operations using wtperf. wtperf doesn't use timestamps and only relies on the txn-ids. We noticed that we were storing txn-ids on the data files all the time, causing a performance hit and much larger data file sizes. Having fixed WT-6082, we got the expected simple operation's performance back and reduced the data file sizes.

      Before WT-6082, in 4.4-rc5 mark.callaghan reported _id index sizes that were 3 to 4 times larger than 4.2.6. After WT-6082, in 4.4-rc6 the reported _id index size is 2 to 3 times larger. We need more work in investigating why we still have a larger index size than 4.2.6 and if we can do something to resolve that. I have filed this ticket to look into this issue.

      Attachments

        1. ftdc.rc6.ibench.tar
          60.21 MB
        2. ftdc.rc6.linkbench.tar
          20.39 MB
        3. image-2020-05-18-09-30-44-631.png
          image-2020-05-18-09-30-44-631.png
          54 kB

        Issue Links

          Activity

            People

              michael.cahill@mongodb.com Michael Cahill
              sulabh.mahajan@mongodb.com Sulabh Mahajan
              Votes:
              0 Vote for this issue
              Watchers:
              8 Start watching this issue

              Dates

                Created:
                Updated:
                Resolved: