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Type: Bug
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Resolution: Fixed
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Priority: Major - P3
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None
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Affects Version/s: 4.2.14, 4.4.6, 5.0.0-rc7
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Component/s: None
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None
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Storage Execution
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Fully Compatible
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ALL
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Execution Team 2021-06-28, QE 2021-11-01, QE 2021-11-15, QE 2021-11-29, QE 2021-12-13, QE 2021-12-27, QE 2022-01-10, QE 2022-02-07, QE 2022-02-21, QE 2022-01-24
Delete performance appears to suffer greatly if there are multiple secondary indexes with the same first field in a key. This does not appear to have an obvious reason, because using a hint improves performance significantly.
For example:
- Say collection has two secondary indexes {a: 1, b: 1} and {a: 1, c: 1} with 10K documents
- Perform a delete on {a: <value>}
- This query takes 5 seconds. If an index is dropped or a hint is used, the same query performance improves to around 200ms.
- As additional indexes are added, performance degrades linearly
Investigate the reason for this discrepancy.
Note: I tested this regression and it exists at least as far back as 4.2
- depends on
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SERVER-58712 Inconsistent update performance on collections with multiple secondary indexes on same key
- Closed
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SERVER-55750 Enable Feature flag for PM-2227
- Closed
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SERVER-65528 Use range bounded cursors for restoring index cursors after yielding
- Closed
- is related to
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SERVER-56274 TTL deletes are much slower on descending indexes than ascending indexes
- Closed
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SERVER-57307 Improve deletion of config.chunks entries with hint and retries
- Closed
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SERVER-56509 Wrap unique index insertion _keyExists call in a WT cursor reconfigure.
- Closed
- related to
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SERVER-58712 Inconsistent update performance on collections with multiple secondary indexes on same key
- Closed
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SERVER-70184 Complete TODO listed in SERVER-57221
- Blocked
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WT-7619 Add a new optimization to skip pages in cursor traversal when all entries on the page are deleted
- Closed