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ea72cf34d6
* Rename BlockwiseLinear to BlockwiseLinearLegacy Reimplements the blockwise multilinear codec using integer arithmetics. Added comments * add estimate for blockwise * Added one unit test * use int based for linear interpol * fix merge conflicts * reuse code * cargo fmt * fix clippy * fix test * fix off by one fix off by one to accurately interpolate autoincrement fields * extend test, fix estimate * remove legacy codec Co-authored-by: Pascal Seitz <pascal.seitz@gmail.com>
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
FastFieldCodecReaderto read the codec. - A serializer implementing
FastFieldCodecSerializerfor 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 |
+----------------------------------+-------------------+------------------------+