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Merge pull request #5436 from Gu1nness/#5336-meaning-statistical-mean 

Change documentation inaccuracy on chunk size.
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TW 2020-10-23 15:49:07 +02:00 committed by GitHub
parent d56c816cf2 61c92110e6
commit aee10b7497
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1 changed files with 3 additions and 3 deletions
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docs/internals/data-structures.rst
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@ -608,8 +608,8 @@ default is not to have a differently sized header chunk).
"buzhash" chunker "buzhash" chunker
+++++++++++++++++ +++++++++++++++++
The buzhash chunker triggers (chunks) when the last HASH_MASK_BITS bits of The buzhash chunker triggers (chunks) when the last HASH_MASK_BITS bits of the
the hash are zero, producing chunks of 2^HASH_MASK_BITS Bytes on average. hash are zero, producing chunks with a target size of 2^HASH_MASK_BITS Bytes.
Buzhash is **only** used for cutting the chunks at places defined by the Buzhash is **only** used for cutting the chunks at places defined by the
content, the buzhash value is **not** used as the deduplication criteria (we content, the buzhash value is **not** used as the deduplication criteria (we
@ -621,7 +621,7 @@ can be used to tune the chunker parameters, the default is:
- CHUNK_MIN_EXP = 19 (minimum chunk size = 2^19 B = 512 kiB) - CHUNK_MIN_EXP = 19 (minimum chunk size = 2^19 B = 512 kiB)
- CHUNK_MAX_EXP = 23 (maximum chunk size = 2^23 B = 8 MiB) - CHUNK_MAX_EXP = 23 (maximum chunk size = 2^23 B = 8 MiB)
- HASH_MASK_BITS = 21 (statistical medium chunk size ~= 2^21 B = 2 MiB) - HASH_MASK_BITS = 21 (target chunk size ~= 2^21 B = 2 MiB)
- HASH_WINDOW_SIZE = 4095 [B] (`0xFFF`) - HASH_WINDOW_SIZE = 4095 [B] (`0xFFF`)
The buzhash table is altered by XORing it with a seed randomly generated once The buzhash table is altered by XORing it with a seed randomly generated once