Internals
Compression
DuckDB uses [lightweight compression](https://duckdb.org/2022/10/28/lightweight-compression).
Note that compression is only applied to persistent databases and is **not applied to in-memory instances**.  
#### Compression Algorithms {#docs:internals:storage::compression-algorithms}  
The compression algorithms supported by DuckDB include the following:  
* [Constant Encoding](https://duckdb.org/2022/10/28/lightweight-compression#constant-encoding)
* [Run-Length Encoding (RLE)](https://duckdb.org/2022/10/28/lightweight-compression#run-length-encoding-rle)
* [Bit Packing](https://duckdb.org/2022/10/28/lightweight-compression#bit-packing)
* [Frame of Reference (FOR)](https://duckdb.org/2022/10/28/lightweight-compression#frame-of-reference)
* [Dictionary Encoding](https://duckdb.org/2022/10/28/lightweight-compression#dictionary-encoding)
* [Fast Static Symbol Table (FSST)](https://duckdb.org/2022/10/28/lightweight-compression#fsst) – [VLDB 2020 paper](https://www.vldb.org/pvldb/vol13/p2649-boncz.pdf)
* [Adaptive Lossless Floating-Point Compression (ALP)](https://duckdb.org/2024/02/13/announcing-duckdb-0100#adaptive-lossless-floating-point-compression-alp) – [SIGMOD 2024 paper](https://ir.cwi.nl/pub/33334/33334.pdf)
* [Chimp](https://duckdb.org/2022/10/28/lightweight-compression#chimp--patas) – [VLDB 2022 paper](https://www.vldb.org/pvldb/vol15/p3058-liakos.pdf)
* [Patas](https://duckdb.org/2022/11/14/announcing-duckdb-060#compression-improvements)