compaction: Fix key estimation per sstable to produce efficient filters #15727
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The estimation assumes that size of other components are irrelevant, when estimating the number of partitions for each output sstable. The sstables are split according to the data file size, therefore size of other files are irrelevant for the estimation. With certain data models, like single-row partitions containing small values, the index could be even larger than data. For example, assume index is as large as data, then the estimation would say that 2x more sstables will be generated, and as a result, each sstable are underestimated to have 2x less keys. Fix it by only accounting size of data file. Fixes scylladb#15726. Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
🟢 CI State: SUCCESS✅ - Build Build Details:
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denesb
approved these changes
Oct 17, 2023
bhalevy
approved these changes
Oct 17, 2023
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The estimation assumes that size of other components are irrelevant, when estimating the number of partitions for each output sstable. The sstables are split according to the data file size, therefore size of other files are irrelevant for the estimation.
With certain data models, like single-row partitions containing small values, the index could be even larger than data.
For example, assume index is as large as data, then the estimation would say that 2x more sstables will be generated, and as a result, each sstable are underestimated to have 2x less keys.
Fix it by only accounting size of data file.
Fixes #15726.