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  1. WiredTiger
  2. WT-5090

Log a message to the event handler when rolling back due to cache full

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    Details

    • Type: Improvement
    • Status: Open
    • Priority: Major - P3
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: Backlog
    • Component/s: None
    • Labels:

      Description

      There is some code in WiredTiger that automatically rolls back the oldest transaction that's done any updates, if the cache gets stuck full:

      https://github.com/wiredtiger/wiredtiger/blob/develop/src/evict/evict_lru.c#L2306

      The filter for "has done any updates" isn't obvious - but it works because the transaction ID only gets allocated the first time a transaction does an update.

      It is an unusual path, and logging something to the message event handler would make diagnosing such a failure mode easier. If logging a message in that case makes internal testing noisier we could consider adding a new verbose=rollback_messages or similar configuration string.

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            • Assignee:
              backlog-server-storage-engines Backlog - Storage Engines Team
              Reporter:
              alexander.gorrod Alexander Gorrod
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              • Created:
                Updated: