vqf

Vector Quotient Filters: Overcoming the Time/Space Trade-Off in Filter Design

This work appeared at SIGMOD 2021. If you use this software please cite us:

@inproceedings{PandeyCDB21,
  author    = {Prashant Pandey and
               Alex Conway and
               Joe Durie and
               Michael A. Bender and
               Martin Farach-Colton and
               Rob Johnson},
  title     = {Vector Quotient Filters: Overcoming the Time/Space Trade-Off in Filter Design},
  booktitle={Proceedings of the 2021 ACM international conference on Management of Data},
  year      = {2021},
}

Overview

The VQF supports approximate membership testing of items in a data set. The VQF is based on Robin Hood hashing, like the quotient filter, but uses power-of-two-choices hashing to reduce the variance of runs, and thus offers consistent, high throughput across load factors. Power-of-two-choices hashing also makes it more amenable to concurrent updates.

API

• 'vqf_insert(item)': insert an item to the filter
• 'vqf_is_present(item)': return the existence of the item. Note that this method may return false positive results like Bloom filters.
• 'vqf_remove(item)': remove the item.

Build

This library depends on libssl.

The code uses AVX512 instructions to speed up operatons. However, there is also an alternate implementation based on AVX2.

 $ make main
 $ ./main 24

To build the code with thread-safe insertions:

 $ make THREAD=1 main_tx
 $ ./main_tx 24 4

The argument to main is the log of the number of slots in the VQF. For example, to create a VQF with 2^30 slots, the argument will be 30.

Contributing

Contributions via GitHub pull requests are welcome.

Authors

• Prashant Pandey [email protected]
• Alex Conway [email protected]
• Rob Johnson [email protected]