storage: avoid heap allocation per value in pebbleIterator.FindSplitKey #58120
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This was fallout from 95b836d. ``` name old time/op new time/op delta MVCCFindSplitKey_Pebble/valueSize=32-16 97.0ms ± 5% 76.5ms ±15% -21.08% (p=0.000 n=9+10) name old speed new speed delta MVCCFindSplitKey_Pebble/valueSize=32-16 693MB/s ± 5% 881MB/s ±13% +27.19% (p=0.000 n=9+10) name old alloc/op new alloc/op delta MVCCFindSplitKey_Pebble/valueSize=32-16 27.8MB ± 0% 0.0MB ±27% -99.99% (p=0.000 n=10+10) name old allocs/op new allocs/op delta MVCCFindSplitKey_Pebble/valueSize=32-16 580k ± 0% 0k ± 0% -100.00% (p=0.000 n=10+9) ``` At the end of a 4 hour, 2.2 TB IMPORT of TPC-E, this was responsible for 15.96% of all heap allocations (by object).
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sumeerbhola
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Dec 21, 2020
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glad you found this!
Reviewed 1 of 1 files at r1.
Reviewable status:complete! 1 of 0 LGTMs obtained
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This was fallout from 95b836d.
pebble.Iterator.Valueis unsafe (no copy) butpebbleIterator.Valueis safe (alloc + copy).At the end of a 4 hour, 2.2 TB IMPORT of TPC-E, this was responsible for 15.96% of all heap allocations (by object).