matanper commented on issue #69916: URL: https://github.com/apache/doris/issues/69916#issuecomment-6555423780
**Update.** We have run a fix in production. Two additions to the proposal above. **1. Share compiled databases across queries, not only across clones.** Even after compiling once per fragment, every fragment instance of every query still compiles its constant LIKE/REGEXP pattern again. Some patterns take seconds to compile, and scheduled queries repeat the same patterns. A per-BE cache of compiled Hyperscan databases, keyed by expression, removes that: - Flags and mode are fixed, so the expression alone is the key. - A compiled database is read-only, so all users share it and each allocates only its own scratch. - Concurrent misses on one expression wait for a single compile. - Eviction is LRU, with a mutable byte cap. - `regexp_fn`, used when the pattern is constant within a block, uses the cache too. - RE2 and Boost fallbacks stay per state, uncached, because RE2 locks its DFA cache on every search. The cache complements #66788. #66788 routes quantifiers above 50 to RE2; everything that stays on Hyperscan, including other compile-heavy shapes, now compiles once per BE. **2. A trap when caching failed compiles.** A cache that keeps patterns Hyperscan rejects, so they go straight to the RE2 fallback, has to tell rejections apart from transient failures. hyperscan 5.4.2 and vectorscan 5.4.11 report "Unable to allocate memory.", "Internal error." and "Allocator returned misaligned memory." with `expression == 0`, despite `hs_compile.h` saying they are negative. So `expression >= 0` is not enough on its own; those three messages have to be retried, not cached. **Result:** a bounded-repeat `(?i)` pattern that takes ~14.8 s to compile drops to ~30 ms on every later run on the same BE. Happy to open a PR with both parts. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
