Pattern matching strings without decompression

Logged at IST: 2026-07-19 23:32 IST

What it is: Spiral/Vortex deep dive on evaluating SQL LIKE predicates directly over FSST-compressed strings.

Gist: The post explains how Vortex can match string patterns in compressed code space instead of decompressing values first. It builds deterministic finite automata over FSST symbol codes, then uses a SIMD Teddy prefilter to cheaply identify candidate positions before running the verifier. On selective patterns like ClickBench Q20’s %google%, the prefilter cuts candidate stops from about ten million to 44,158 and confirms 646 true matches, producing roughly 2.4x to 3.6x single-thread speedups across tested x86 machines, with smaller but still positive wins at high thread counts.

Newsletter angle: Strong database-systems piece because it shows compression as an execution format, not only a storage format: predicate pushdown can operate over encoded data when the codec preserves enough structure.