Thanks for reaching out. Changing the compressor for a table is both safe and common. Future flushes / compactions will use the new codec as SSTables are written, and SSTables currently present on disk will remain readable with the previous codec.
You may also want to take a look at the Zstandard codec once you’ve upgraded to Cassandra 4.0+, which offers a great balance between compression ratio and throughout. > On Sep 19, 2022, at 11:34 PM, Eunsu Kim <eunsu.bil...@gmail.com> wrote: > > Hi all > > According to > https://docs.datastax.com/en/cql-oss/3.3/cql/cql_reference/cqlAlterTable.html, > it can be very problematic to modify the Compaction strategy on a table > running in production. > > Similarly, is it risky to change the compression algorithm to existing table > in production? > > Currently the table is using DeflateCompressor but I want to change it to > LZ4Compressor(for performance) Cassandra version is 3.11.10. > > > Thank you in advance.