On Mon, Aug 3, 2026 at 10:36 PM Tomas Vondra <[email protected]> wrote: > > On 8/3/26 15:36, Hannu Krosing wrote: > > For the CPU usage vs compression ratio discussion, please remember > > that for both lz4 and zstd this depends on certain "compression > > effort" flags, which we do not expose to customers (we claim we > > already choose the best ones for them :) ) > > > > I'm not sure we really make such claims.
Yeah, I re-checked and all the claims I remembered were from mailing list discussions, not official docs. > AFAIK we simply use the default > compression levels, specified by the lz4/zstd library, and assume the > authors picked the right trade offs. I think that's sensible. It's a bit more complicated than that - we use zstd level 1 while the default for the zstd command-line utility is level 3 We should keep this in mind when running any manual compression tests. My recollection from running some manual tests a year or two ago is that on compression side there was a fair bit of overlap in speed between lz4 and zstd when looking across many compression levels. However, lz4 was a clear winner in decompression speeds, being 2-3 times faster than zstd. ---- Hannu Krosing
