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Type:
Improvement
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Resolution: Unresolved
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Priority:
Major - P3
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None
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Affects Version/s: None
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Component/s: Configuration
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Storage Engines, Storage Engines - Foundations
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Megabat - 2024-05-14, SE Foundations - 2025-06-06
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3
We tried to remove the MongoDB cursor caching layer in SERVER-82970, but we found regressions caused by extra overhead in the WiredTiger cursor caching layer.
The main sources of overhead seem to come from two places:
- Config string parsing
- Having to close and re-open the actual dhandle. In the MongoDB layer, we just call reset() when caching a cursor, which does not appear to incur the same overhead.
In the mixed_multi_deletes_batched workload, this is the time spent constructing a WiredTigerCursor:
- Before: 3.0%
- After: 6.6%
And this is zoomed into the unindex path:
Before:
After:
- is related to
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SERVER-89811 Evaluate setting wiredTigerCursorCacheSize to 100
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- Closed
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- Closed
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- related to
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- Open
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- Closed
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