Investigate CE cache performance degradation for large MatchExpressions

    • Type: Improvement
    • Resolution: Unresolved
    • Priority: Major - P3
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    • Affects Version/s: None
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    • Query Optimization
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      SERVER-124126 disabled the CE cache when an IXSCAN plan has more than a threshold number of intervals, at which point the cost of converting the intervals to a MatchExpression and hashing it to check for a matching key in the CE cache outweighs the cost of performing cardinality estimation.

      Since this fix only applies for plans with index bounds, investigate whether a similar issue exists for COLLSCAN filters being checked for/inserted into the CE cache.

      See SERVER-108776 for examples of what the performance issues looked like with IXSCAN plans.

            Assignee:
            Unassigned
            Reporter:
            Natalie Hill
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              Created:
              Updated: