ydb/library/cpp/yt/misc/unittests/hash_ut.cpp, branch oidc-1.2.8.12-devMirror of YDB github reposhttps://code.mastervirt.ru/ydb/atom?h=oidc-1.2.8.12-dev2026-03-05T10:11:05Z[yt] make SplitMix & HashCombine bit-independent2026-03-05T10:11:05Zvaskovasko@yandex-team.com2026-03-05T08:17:14Zurn:sha1:d0739058c7dbc0e2e2b8aa6c5bc399522d5e6fca
add realization of hash-functions for 32-bit platforms
commit_hash:3247a0524d3b66d759bf5ebd598be84c8dfb5837
YT-27167: Better TBitwiseUnversionedValueHash2026-02-11T01:27:50Zpavookpavook@yandex-team.com2026-02-11T01:03:48Zurn:sha1:72e2e4fb5634001484795bce3f6ca27e21b24905
+20-30% throughput on UpdateColumnarStatistics benchmark (with large statistics enabled)
- Do not factor in value.Id when calculating column digest
- Pack metadata directly instead of multiple HashCombine calls
- Use SplitMix64 finalizer for proper bit distribution
- Use cheaper xor with metadata instead of HashCombine
- Use XXH3 for strings
- Remove unnecessary copy
- Measured quality increased: on 20 (c=1..20) sequences `{nc | n \in [1..10^6]}` MAE dropped from ~36% to ~20%
HLL digests might temporarily suffer a 2x increase upon merging with the previously computed ones.
commit_hash:0bf661245cf1848ba9ef8b6c840c18dfd05bd2a4
NaN-safe comparison and hashing2024-11-06T10:54:01Zbabenkobabenko@yandex-team.com2024-11-06T10:24:38Zurn:sha1:b60a78031c047a8c8543bf6a3dc4f828d104dd3c
commit_hash:46d59ab3acbd313753d3e46f3a6f10a8ebc424d8