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A high performance persistent bloom filter

Project Description

[![Build Status](](

Hydra: The Python Bloom Filter.

Compile with Cython 0.24 or higher.

Hydra is a high performance bloom filter. It’s basically a port of the Cassandra bloom filter with some fun Cython hackery.

1) It’s persistent using memory mapped io. On Linux, the mmap uses the MAP_POPULATE flag so the entire file is loaded into kernel space virtual memory. In other words - fast.

2) The hash function uses the MurmurHash3 algorithm, so it should be fast and have excellent key distribution and avalanche properties.

3) The filter exports a set-like interface. Use .add(..), .contains() or use the “in” operator.

  1. Tests. OMG what is wrong with people with no tests?

The filter supports periodic forced synchronization to disk using fdatasync(), or you can just let the deallocator flush everything to disk when your filter goes out of scope, or your process terminates.

Hydras are snakes with multiple heads. They’re also bad dudes with snake logos on their chest who regularly try to beat on Nick Fury. Now it’s a bloom filter.

Mostly, I couldn’t bear to make this yet another PySomeLibraryName library.

Build, install a dev build and test:

$ pip install -r requirements.txt $ cythonize src/_hydra.pyx $ python develop $ python test

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