Keyvi - the short form for "Key value index" - defines a special subtype of the popular key value store (KVS) technologies. As you can imagine from the name, keyvi is an immutable key value store, therefore an index not a store. Keyvi's strengths: high compression ratio and extreme scalability. So if you need online read/writes keyvi is not for you, however, if your use case is mostly reads and infrequent writes you might be interested in checking keyvi out.
Build status
| Linux | Coveralls |
|---|---|
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Install
Quick
Precompiled binaries for Ubuntu 14.04LTS are available at the keyvi PPA. To install use:
sudo add-apt-repository ppa:hendrik-muhs/keyvi
sudo apt-get update
sudo apt-get install keyvi python-keyvi
From Source
The core part is a C++ header-only library, but the TPIE 3rdparty library needs to be compiled once. The commandline tools are also part of the C++ code. For instructions check the Readme file.
For the python extension pykeyvi check the Readme file in the pykeyvi subfolder.
Read
Usage
- Howtos
- [Compiling Dictionaries/Indexes](/doc/usage/Building keyvi dictionaries.md)
- Pykeyvi
- [Compiling](/doc/usage/Building keyvi dictionaries with python.md)
- Crashcourse
- [Using pykeyvi with EMR (mrjob or pyspark)](/doc/usage/Using pykeyvi in EMR.md)
Development
- [Build/Packaging](/doc/development/Packaging keyvi.md)
Internals
If you like to go deep down in the basics, keyvi is inspired by the following 2 papers:
- Sparse Array (See Storing a Sparse Table, Robert E. Tarjan et al. http://infolab.stanford.edu/pub/cstr/reports/cs/tr/78/683/CS-TR-78-683.pdf)
- Incremental, which means minimization is done on the fly (See Incremental Construction of Minimal Acyclic Finite-State Automata, J. Daciuk et al.: http://www.mitpressjournals.org/doi/pdf/10.1162/089120100561601)
Licence and 3rdparty dependencies
keyvi is licenced under apache license 2.0, see licence for details.
In addition keyvi uses 3rdparty libraries which define their own licence. Please check their respective licence. The 3rdparty libraries can be found at keyvi/3rdparty.