v.24.2New Feature

LZ4HC Codec Adds Faster Level 2 with Reduced Compression

The codec LZ4HC will accept a new level 2, which is faster than the previous minimum level 3, at the expense of less compression. In previous versions, LZ4HC(2) and less was the same as LZ4HC(3). Author: Cyan4973. #60090 (Alexey Milovidov).
The LZ4HC codec in ClickHouse now supports a new compression level 2, which is faster than the previous minimum level 3 but provides less compression.

Why it matters

This feature allows users to choose a faster compression level for LZ4HC, improving compression speed at the cost of reduced compression ratio. It is useful for scenarios where compression speed is more critical than compression ratio.

How to use it

To use the new compression level, specify LZ4HC(2) as the codec in your table or column compression settings. Previously, LZ4HC(2) was treated the same as LZ4HC(3), but now it provides a faster compression option.