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author | Keith Bostic <keith@wiredtiger.com> | 2012-09-17 12:47:04 +0000 |
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committer | Keith Bostic <keith@wiredtiger.com> | 2012-09-17 12:47:04 +0000 |
commit | 1b35ca42e02af9539fa62ab56732b33230e856b0 (patch) | |
tree | cc9e9a0e9d48296d94fcdac181cee90c839ca9bc | |
parent | 674152f0e5b01f3a18fdeca285267a10a0136f95 (diff) | |
download | mongo-1b35ca42e02af9539fa62ab56732b33230e856b0.tar.gz |
Replace "stream" with "block", it's clearer.
-rw-r--r-- | src/docs/architecture.dox | 20 | ||||
-rw-r--r-- | src/docs/file-formats.dox | 18 |
2 files changed, 19 insertions, 19 deletions
diff --git a/src/docs/architecture.dox b/src/docs/architecture.dox index 595cd728d4d..71781fe633a 100644 --- a/src/docs/architecture.dox +++ b/src/docs/architecture.dox @@ -53,13 +53,13 @@ same file. Applications can maximize the amount of data transferred in each I/O by configuring large leaf pages, and still minimize CPU cache misses when searching the tree. +WiredTiger supports key prefix encoding and value dictionaries, reducing +the amount of memory keys and values require. + WiredTiger supports static encoding with a configurable Huffman engine, which typically reduces the amount of information maintained in memory by 20-50%. -WiredTiger supports key prefix encoding, reducing the number of bytes -from each key maintained in memory. - @section io Making I/O more valuable WiredTiger uses compact file formats to minimize on-disk overhead. @@ -73,13 +73,13 @@ WiredTiger supports variable-length pages, meaning there is less wasted space for large objects, and no need for compaction as pages grow and shrink naturally when key/value pairs are inserted or deleted. -WiredTiger supports stream compression on every page of a table. -Because WiredTiger supports variable-length pages, pages do not have to -shrink by a fixed amount in order to benefit from stream compression. -Stream compression is selectable on a per-table basis, allowing -applications to choose the compression algorithm most appropriate for -their data. Stream compression typically reduces the amount of -information written to disk by 30-80%. +WiredTiger supports block compression on table pages. Because +WiredTiger supports variable-length pages, pages do not have to shrink +by a fixed amount in order to benefit from block compression. Block +compression is selectable on a per-table basis, allowing applications +to choose the compression algorithm most appropriate for their data. +Block compression typically reduces the amount of information written +to disk by 30-80%. WiredTiger supports leaf pages of up to 512MB in size. Disk seeks are less likely when reading large amounts of data from disk, significantly diff --git a/src/docs/file-formats.dox b/src/docs/file-formats.dox index 0b4c0f21592..8a35de4b782 100644 --- a/src/docs/file-formats.dox +++ b/src/docs/file-formats.dox @@ -39,7 +39,7 @@ maximum file allocation unit is 512MB. File block offsets are 64-bit @section file_formats_compression File formats and compression Row-stores support four types of compression: prefix compression, -dictionary compression, Huffman encoding and stream compression. +dictionary compression, Huffman encoding and block compression. - Prefix compression reduces the size requirement of both in-memory and on-disk objects by storing any identical key prefix only once per page. @@ -63,15 +63,15 @@ from the in-memory tree and when writing pages to disk. Note the additional CPU cost of Huffman encoding can be high, and should be considered. (See @subpage huffman for details) -- Stream compression reduces the size requirement of on-disk objects by +- Block compression reduces the size requirement of on-disk objects by compressing blocks of the backing object's file. The cost is additional CPU and memory use when reading and writing pages to disk. Note the -additional CPU cost of stream compression can be high, and should be +additional CPU cost of block compression can be high, and should be considered. (See @ref compression for details). Column-stores with variable-length byte string values support three types of compression: run-length encoding, Huffman encoding and block -stream compression. +compression. - Run-length encoding reduces the size requirement of both the in-memory and on-disk objects by storing sequential, duplicate values in the store @@ -86,19 +86,19 @@ tree and when writing pages to disk. Note the additional CPU cost of Huffman encoding can be high, and should be considered. (See @ref huffman for details) -- Stream compression reduces the size requirement of on-disk objects by +- Block compression reduces the size requirement of on-disk objects by compressing blocks of the backing object's file. The cost is additional CPU and memory use when reading and writing pages to disk. Note the -additional CPU cost of stream compression can be high, and should be +additional CPU cost of block compression can be high, and should be considered. (See @ref compression for details). Column-stores with fixed-length byte values support a single type of -compression: stream compression. +compression: block compression. -- Stream compression reduces the size requirement of on-disk objects by +- Block compression reduces the size requirement of on-disk objects by compressing blocks of the backing object's file. The cost is additional CPU and memory use when reading and writing pages to disk. Note the -additional CPU cost of stream compression can be high, and should be +additional CPU cost of block compression can be high, and should be considered. (See @ref compression for details). */ |