fork of https://github.com/oxigraph/rocksdb and https://github.com/facebook/rocksdb for nextgraph and oxigraph

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Siying Dong 0bb555630f Consolidate hash function used for non-persistent data in a new function (#5155) ... Summary: Create new function NPHash64() and GetSliceNPHash64(), which are currently implemented using murmurhash. Replace the current direct call of murmurhash() to use the new functions if the hash results are not used in on-disk format. This will make it easier to try out or switch to alternative functions in the uses where data format compatibility doesn't need to be considered. This part shouldn't have any performance impact. Also, the sharded cache hash function is changed to the new format, because it falls into this categoery. It doesn't show visible performance impact in db_bench results. CPU showed by perf is increased from about 0.2% to 0.4% in an extreme benchmark setting (4KB blocks, no-compression, everything cached in block cache). We've known that the current hash function used, our own Hash() has serious hash quality problem. It can generate a lots of conflicts with similar input. In this use case, it means extra lock contention for reads from the same file. This slight CPU regression is worthy to me to counter the potential bad performance with hot keys. And hopefully this will get further improved in the future with a better hash function. cache_test's condition is relaxed a little bit to. The new hash is slightly more skewed in this use case, but I manually checked the data and see the hash results are still in a reasonable range. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5155 Differential Revision: D14834821 Pulled By: siying fbshipit-source-id: ec9a2c0a2f8ae4b54d08b13a5c2e9cc97aa80cb5		5 years ago
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cache_bench.cc	comment unused parameters to turn on -Wunused-parameter flag	6 years ago
cache_test.cc	Consolidate hash function used for non-persistent data in a new function (#5155)	5 years ago
clock_cache.cc	Add final annotations to some cache functions (#5156)	5 years ago
clock_cache.h	Change RocksDB License	7 years ago
lru_cache.cc	Make adaptivity of LRU cache mutexes configurable (#5054)	5 years ago
lru_cache.h	Add final annotations to some cache functions (#5156)	5 years ago
lru_cache_test.cc	Make adaptivity of LRU cache mutexes configurable (#5054)	5 years ago
sharded_cache.cc	Revert "Move MemoryAllocator option from Cache to BlockBasedTableOpti… (#4697)	6 years ago
sharded_cache.h	Consolidate hash function used for non-persistent data in a new function (#5155)	5 years ago