diff options
Diffstat (limited to 'src/docs/tune-compression.dox')
| -rw-r--r-- | src/docs/tune-compression.dox | 62 |
1 files changed, 0 insertions, 62 deletions
diff --git a/src/docs/tune-compression.dox b/src/docs/tune-compression.dox deleted file mode 100644 index 8db2151aa76..00000000000 --- a/src/docs/tune-compression.dox +++ /dev/null @@ -1,62 +0,0 @@ -/*! @page tune_compression Compression - -WiredTiger includes a number of optional compression techniques. Configuring -compression generally decreases on-disk and in-memory resource requirements -and the amount of I/O, and increases CPU cost when data are read and written. - -Configuring compression may change application throughput. For example, -in applications using solid-state drives (where I/O is less expensive), -turning off compression may increase application performance by reducing -CPU costs; in applications where I/O costs are more expensive, turning on -compression may increase application performance by reducing the overall -number of I/O operations. - -An example of turning on row-store key prefix compression: - -@snippet ex_all.c Configure key prefix compression on - -An example of turning on row-store or column-store dictionary compression: - -@snippet ex_all.c Configure dictionary compression on - -@section compression_formats Block Compression Formats -WiredTiger provides two methods of compressing your data when using block -compression: the raw and noraw methods. These methods change how WiredTiger -works to fit data into the blocks that are stored on disk. - -@subsection noraw_compression Noraw Compression -Noraw compression is the traditional compression model where a fixed -amount of data is given to the compression system, then turned into a -compressed block of data. The amount of data chosen to compress is the -data needed to fill the uncompressed block. Thus when compressed, the block will -be smaller than the normal data size and the sizes written to disk will often -vary depending on how compressible the data being stored is. Algorithms -using noraw compression include zlib-noraw, lz4-noraw and snappy. - -@subsection raw_compression Raw Compression -WiredTiger's raw compression takes advantage of compressors that provide a -streaming compression API. Using the streaming API WiredTiger will try to fit -as much data as possible into one block. This means that blocks created -with raw compression should be of similar size. Using a streaming compression -method should also make for less overhead in compression, as the setup and -initial work for compressing is done fewer times compared to the amount of -data stored. Algorithms using raw compression include zlib, lz4. - -@subsection to_raw_or_noraw Choosing between Raw and Noraw Compression -When looking at which compression method to use the biggest consideration is -that raw compression will normally provide higher compression levels while -using more CPU for compression. - -An additional consideration is that raw compression may provide a performance -advantage in workloads where data is accessed sequentially. That is because -more data is generally packed into each block on disk. Conversely, noraw -compression may perform better for workloads with random access patterns -because each block will tend to be smaller and require less work to read and -decompress. - -See @ref file_formats_compression for more information on available -compression techniques. - -See @ref compression for information on how to configure and enable compression. - - */ |