![]() ![]() In 2018 the algorithm was published as RFC 8478, which also defines an associated media type "application/zstd", filename extension "zst", and HTTP content encoding "zstd". Support was added to Debian (and subsequently, Ubuntu) in April 2018 (in version 1.6~rc1). ![]() Compared with xz compression of deb packages, zstd at level 19 decompresses significantly faster, but at the cost of 6% larger package files. In March 2018, Canonical tested the use of zstd as a deb package compression method by default for the Ubuntu Linux distribution. The AWS Redshift and RocksDB databases include support for field compression using Zstandard. It was also used to create a proof-of-concept OpenZFS compression method which was integrated in 2020. In 2017, Allan Jude integrated Zstandard into the FreeBSD kernel, and it was subsequently integrated as a compressor option for core dumps (both user programs and kernel panics). The Linux kernel has included Zstandard since November 2017 (version 4.14) as a compression method for the btrfs and squashfs filesystems. com /facebook /zstd /blob /dev /doc /zstd _compression _format. ![]() Because of the way that FSE carries over state between symbols, decompression involves processing symbols within the Sequences section of each block in reverse order (from last to first). It uses both Huffman coding (used for entries in the Literals section) and finite-state entropy (FSE) - a fast tabled version of ANS, tANS, used for entries in the Sequences section. Zstandard combines a dictionary-matching stage ( LZ77) with a large search window and a fast entropy-coding stage. In particular, one dictionary can be loaded to process large sets of files with redundancy between files, but not necessarily within each file, e.g., log files. It also offers a training mode, able to generate a dictionary from a set of samples. ĭictionaries can have a large impact on the compression ratio of small files, so Zstandard can use a user-provided compression dictionary. Zstandard reaches the current Pareto frontier, as it decompresses faster than any other currently available algorithm with similar or better compression ratio. Lzham, and ppmx, and performs better than lza, or bzip2. Zstd at its maximum compression level gives a compression ratio close to lzma, Zstandard command-line has an "adaptive" ( -adapt) mode that varies compression level depending on I/O conditions, mainly how fast it can write the output. Ĭompression speed can vary by a factor of 20 or more between the fastest and slowest levels, while decompression is uniformly fast, varying by less than 20% between the fastest and slowest levels. Starting from version 1.3.2 (October 2017), zstd optionally implements very long range search and deduplication ( -long, 128 MiB window) similar to rzip or lrzip. It is tunable with compression levels ranging from negative 7 (fastest) to 22 (slowest in compression speed, but best compression ratio). Zstandard was designed to give a compression ratio comparable to that of the DEFLATE algorithm (developed in 1991 and used in the original ZIP and gzip programs), but faster, especially for decompression. Version 1 of this implementation was released as open-source software on 31 August 2016. ![]() Zstd is the reference implementation in C. Zstandard, commonly known by the name of its reference implementation zstd, is a lossless data compression algorithm developed by Yann Collet at Facebook. ![]()
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