Does timescale do it’s own compression alg too? I see in pg 14 toast column compression can be lz4 instead of ootb pglz which has a few probs appr, I see mentions on the mailing list of significant possible optimizations. When dealing with EBS style storage where read latencies can be multi millis compression is always going to be a win, but is an easy optimization either way I’d think.
Timescale implements its own compression algorithms. It includes several ones, and automatically applies the choice of algorithm based on the data types of columns.
- Gorilla compression for floats
- Delta-of-delta + Simple-8b with run-length encoding compression for timestamps and other integer-like types
- Whole-row dictionary compression for columns with a few repeating values (+ LZ compression on top)
- LZ-based array compression for all other types
This means within even the same table, different columns will be compressed using different algorithms based on their type (or inferred entropy).