storage: optimize DeleteRange when deleting entire Raft range
#85522
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CC @ajwerner, relevant for schema GC. Btw, there's a risk here that if the MVCC stats are completely off then we may not run MVCC GC. Maybe schema GC should do a stats scan for any ranges with estimates, to make sure we correctly account for the garbage and that MVCC GC will pick it up? |
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This patch adds a fast path for `DeleteRange` when deleting an entire Raft range, by simply marking all live data as deleted in MVCC stats instead of scanning across all point keys. It will still perform a time-bound scan to look for conflicts with newer writes, and a range key scan to take range key fragmentation into account for stats. There are no behavioral changes. The fast path is therefore tested comprehensively by adding a metamorphic parameter for it in `TestMVCCHistories`. Benchmarks confirm that the fast path is ~constant, while the slow path is asymptotically linear. ``` BenchmarkMVCCDeleteRangeUsingTombstone_Pebble/numKeys=1000/valueSize=64/entireRange=false-24 499 2319384 ns/op 48.29 MB/s BenchmarkMVCCDeleteRangeUsingTombstone_Pebble/numKeys=1000/valueSize=64/entireRange=true-24 577 1965157 ns/op 56.99 MB/s BenchmarkMVCCDeleteRangeUsingTombstone_Pebble/numKeys=10000/valueSize=64/entireRange=false-24 216 5531790 ns/op 202.47 MB/s BenchmarkMVCCDeleteRangeUsingTombstone_Pebble/numKeys=10000/valueSize=64/entireRange=true-24 576 2014470 ns/op 555.98 MB/s BenchmarkMVCCDeleteRangeUsingTombstone_Pebble/numKeys=100000/valueSize=64/entireRange=false-24 32 37814215 ns/op 296.18 MB/s BenchmarkMVCCDeleteRangeUsingTombstone_Pebble/numKeys=100000/valueSize=64/entireRange=true-24 589 2022481 ns/op 5537.75 MB/s ``` Release note: None
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TFTR! bors r=aliher1911 |
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This patch adds a fast path for
DeleteRangewhen deleting an entireRaft range, by simply marking all live data as deleted in MVCC stats
instead of scanning across all point keys. It will still perform a
time-bound scan to look for conflicts with newer writes, and a range key
scan to take range key fragmentation into account for stats.
There are no behavioral changes. The fast path is therefore tested
comprehensively by adding a metamorphic parameter for it in
TestMVCCHistories.Benchmarks confirm that the fast path is ~constant, while the slow path
is asymptotically linear.
Resolves #83696.
Release note: None