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  1. WiredTiger
  2. WT-3766

Lookaside sweep for obsolete updates

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Details

    • Improvement
    • Status: Closed
    • Major - P3
    • Resolution: Fixed
    • None
    • 3.6.3, 3.7.2, WT3.1.0
    • None
    • Storage 2018-01-29, Storage 2018-02-12
    • v3.6

    Description

      We currently only sweep the lookaside table after a drop (to free lookaside entries for dropped trees).

      It would improve efficiency of reads and reduce the disk footprint of the lookaside table if we could sweep obsolete entries as well. To do this, we would need to mark which entry in the lookaside table is the on-page version. Sweep would track for each key when it has seen a stable update with a full copy of data, and could remove entries for the key after that. The on-page entry can also be removed once it is globally visible.

      Attachments

        Issue Links

          causes

          Bug - A problem which impairs or prevents the functions of the product. WT-3982 Fix transaction visibility bugs related to lookaside usage.

          • Blocker - P1 - Blocks development and/or testing work, production could not run.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. WT-3891 Take the sweep walk rwlock whenever removing content from lookaside

          • Major - P3 - Major loss of function.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. WT-5150 LAS sweep is not removing the entries that are no longer required

          • Major - P3 - Major loss of function.
          • Closed
          depends on

          Bug - A problem which impairs or prevents the functions of the product. WT-3878 Iteration can lose its position when updating a limbo page

          • Major - P3 - Major loss of function.
          • Closed

          Improvement - An improvement or enhancement to an existing feature or task. WT-3768 Lookaside optimization: birthmarks

          • Major - P3 - Major loss of function.
          • Closed
          is depended on by

          Bug - A problem which impairs or prevents the functions of the product. SERVER-32154 Unbounded lookaside table growth during insert workload

          • Major - P3 - Major loss of function.
          • Closed

          Improvement - An improvement or enhancement to an existing feature or task. WT-3805 Avoid reading lookaside pages in truncate fast path

          • Major - P3 - Major loss of function.
          • Closed
          is duplicated by

          Improvement - An improvement or enhancement to an existing feature or task. WT-3737 Enahance lookaside sweep to remove aged out entries

          • Major - P3 - Major loss of function.
          • Closed
          is related to

          Bug - A problem which impairs or prevents the functions of the product. SERVER-32547 Mongo stalls while evicting dirty cache

          • Major - P3 - Major loss of function.
          • Closed
          related to

          Bug - A problem which impairs or prevents the functions of the product. SERVER-32154 Unbounded lookaside table growth during insert workload

          • Major - P3 - Major loss of function.
          • Closed
          links to

          Web Link https://github.com/wiredtiger/wiredtiger/pull/3897

          Activity

            People

              sue.loverso@mongodb.com Susan LoVerso
              michael.cahill@mongodb.com Michael Cahill (Inactive)
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              Dates

                Created:
                Updated:
                Resolved: