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Type: Task
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Resolution: Done
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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: Compaction
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None
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Storage Engines
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3
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2024-02-06 tapioooooooooooooca
The work in SERVER-80124 led to this specific scenario:
- Compaction is executed on a table where blocks from the end of the file can be re-written to the start of the file.
- In parallel and, before the blocks selected by compaction are re-written, data is inserted into those blocks at the start of the file by another writer.
- This can happen as the first-fit strategy is set on the file as soon as compaction starts.
- Compaction does little work and keeps trying which impacts performance.
The test should implement the scenario described above and understand why compaction continues and where are the blocks re-written.
In theory, if the previously freed blocks are no longer available, it is possible that compaction may extend the file to rewrite the selected blocks bu t this needs to be proven.
- is related to
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SERVER-80124 Measure performance impact of background compaction
- Closed