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  1. WiredTiger
  2. WT-6490

Acquire snapshot for eviction threads

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Details

    • Improvement
    • Status: Closed
    • Major - P3
    • Resolution: Fixed
    • None
    • WT10.0.0, 4.4.2, 4.9.0
    • None
    • None
    • 5
    • Storage - Ra 2020-09-07, Storage - Ra 2020-09-21, Storage - Ra 2020-10-19

    Description

      At the moment eviction threads use checks based on global visibility rules - which means that they don't evict anything that isn't globally visible (based on transaction ID checks, not timestamp checks).

      We should update eviction so that it can evict anything that is committed or prepared. A possible way to do that is to allocate a transaction snapshot when doing evictions, but that requires care because application threads might be doing the eviction and we need to be careful not to use or disrupt their snapshot.

      See WT-6444 for more context and a workload where this change is beneficial.

      Attachments

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        2. a-2.png
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        3. a-3.png
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        4. eviction.patch
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        5. FTDC_base.zip
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        6. FTDC_eviction_improvement.zip
          1.81 MB
        7. image-2020-08-20-10-22-34-887.png
          image-2020-08-20-10-22-34-887.png
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        8. image-2020-08-20-10-38-59-705.png
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        9. image-2020-08-20-10-49-07-353.png
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        10. Screen Shot 2020-08-18 at 4.32.35 pm.png
          Screen Shot 2020-08-18 at 4.32.35 pm.png
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        11. Screen Shot 2020-08-18 at 4.33.54 pm.png
          Screen Shot 2020-08-18 at 4.33.54 pm.png
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        Issue Links

          causes

          Bug - A problem which impairs or prevents the functions of the product. WT-7995 Fix the global visibility so that it cannot go beyond checkpoint visibility

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

          Build Failure - WT-6725 Skip checking visibility for updates restored from disk

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

          Build Failure - WT-6740 Fix unintentionally releasing the snapshot by mistreating the recovery session as an eviction session

          • Major - P3 - Major loss of function.
          • Closed
          has to be done before

          Task - A task that needs to be done. WT-6624 Use transaction snapshot for applications performing eviction

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

          Bug - A problem which impairs or prevents the functions of the product. SERVER-47681 Background validation uses the kNoOverlap read source instead of kAllDurableSnapshot to prevent us from having to take the PBWM lock on secondaries

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

          Build Failure - WT-6726 test_txn24.test_snapshot_isolation_and_eviction failed with WT_ROLLBACK

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

          Bug - A problem which impairs or prevents the functions of the product. WT-6503 Cache stuck: eviction couldn't able to progress triggered by number of updates in cache

          • Critical - P2 - Crashes, loss of data, severe memory leak.
          • Closed
          related to

          Bug - A problem which impairs or prevents the functions of the product. WT-6444 Abort a transaction if it is force evicting and oldest

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

          Bug - A problem which impairs or prevents the functions of the product. WT-6524 Data mismatch between primary and secondaries in mongodb

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

          Improvement - An improvement or enhancement to an existing feature or task. WT-6707 Allow eviction to operate with snapshot when checkpoint is running

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

          Activity

            People

              haseeb.bokhari@mongodb.com Haseeb Bokhari (Inactive)
              alexander.gorrod@mongodb.com Alexander Gorrod
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              Dates

                Created:
                Updated:
                Resolved: