Files
tantivy/fastfield_codecs
dependabot[bot] fc24842a43 Update more-asserts requirement from 0.2.1 to 0.3.0 (#1384)
Updates the requirements on [more-asserts](https://github.com/thomcc/rust-more-asserts) to permit the latest version.
- [Release notes](https://github.com/thomcc/rust-more-asserts/releases)
- [Commits](https://github.com/thomcc/rust-more-asserts/compare/v0.2.2...v0.3.0)

---
updated-dependencies:
- dependency-name: more-asserts
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
2022-06-10 10:38:28 +09:00
..
2022-01-28 15:55:55 +09:00
2022-03-03 11:25:06 +01:00
2021-06-15 09:19:39 +02:00

Fast Field Codecs

This crate contains various fast field codecs, used to compress/decompress fast field data in tantivy.

Contributing

Contributing is pretty straightforward. Since the bitpacking is the simplest compressor, you can check it for reference.

A codec needs to implement 2 traits:

  • A reader implementing FastFieldCodecReader to read the codec.
  • A serializer implementing FastFieldCodecSerializer for compression estimation and codec name + id.

Tests

Once the traits are implemented test and benchmark integration is pretty easy (see test_with_codec_data_sets and bench.rs).

Make sure to add the codec to the main.rs, which tests the compression ratio and estimation against different data sets. You can run it with:

cargo run --features bin

TODO

  • Add real world data sets in comparison
  • Add codec to cover sparse data sets

Codec Comparison

+----------------------------------+-------------------+------------------------+
|                                  | Compression Ratio | Compression Estimation |
+----------------------------------+-------------------+------------------------+
| Autoincrement                    |                   |                        |
+----------------------------------+-------------------+------------------------+
| LinearInterpol                   | 0.000039572664    | 0.000004396963         |
+----------------------------------+-------------------+------------------------+
| MultiLinearInterpol              | 0.1477348         | 0.17275847             |
+----------------------------------+-------------------+------------------------+
| Bitpacked                        | 0.28126493        | 0.28125                |
+----------------------------------+-------------------+------------------------+
| Monotonically increasing concave |                   |                        |
+----------------------------------+-------------------+------------------------+
| LinearInterpol                   | 0.25003937        | 0.26562938             |
+----------------------------------+-------------------+------------------------+
| MultiLinearInterpol              | 0.190665          | 0.1883836              |
+----------------------------------+-------------------+------------------------+
| Bitpacked                        | 0.31251436        | 0.3125                 |
+----------------------------------+-------------------+------------------------+
| Monotonically increasing convex  |                   |                        |
+----------------------------------+-------------------+------------------------+
| LinearInterpol                   | 0.25003937        | 0.28125438             |
+----------------------------------+-------------------+------------------------+
| MultiLinearInterpol              | 0.18676           | 0.2040086              |
+----------------------------------+-------------------+------------------------+
| Bitpacked                        | 0.31251436        | 0.3125                 |
+----------------------------------+-------------------+------------------------+
| Almost monotonically increasing  |                   |                        |
+----------------------------------+-------------------+------------------------+
| LinearInterpol                   | 0.14066513        | 0.1562544              |
+----------------------------------+-------------------+------------------------+
| MultiLinearInterpol              | 0.16335973        | 0.17275847             |
+----------------------------------+-------------------+------------------------+
| Bitpacked                        | 0.28126493        | 0.28125                |
+----------------------------------+-------------------+------------------------+