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  1. WiredTiger
  2. WT-5606

Read a consistent view of the history store when verifying

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major - P3
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 4.3 Desired
    • Component/s: None
    • Labels:
      None
    • Story Points:
      1
    • Sprint:
      Storage - Tora 2020-05-04

      Description

      When reading the history store as part of verify, we do not have a consistent view of the underlying table. The history store can be modified while we are trying to verify, which is not ideal. WT-5541 tried addressing this by:

      • take a transaction - we can't do that because some of the code that walks the history store is wrapped under WT_WITH_PAGE_INDEX
      • hold a snapshot - that doesnt work because the history store walk can call search() on the history store cursor which refreshes the snapshot.

      History store also doesn't follow the usual transaction semantics as the updates carry transaction-ids from the original commit to the data store. This also prevents us from reading as of a snapshot to get a consistent view. For now, we are reverting the changes using WT-5556.

      We will use this ticket to find a better solution to this problem.

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              Assignee:
              sue.loverso Susan LoVerso
              Reporter:
              sulabh.mahajan Sulabh Mahajan
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                Resolved: