On Tue, Oct 24, 2023 at 7:49 PM Tatsuo Ishii <is...@sraoss.co.jp> wrote: > I am impressed the simple NFA implementation.
Thanks! > It would be nicer if it > could be implemented without using recursion. Yeah. If for some reason we end up going with a bespoke implementation, I assume we'd just convert the algorithm to an iterative one and optimize it heavily. But I didn't want to do that too early, since it'd probably make it harder to add new features... and anyway my goal is still to try to reuse src/backend/regex eventually. > > SELECT aid, first_value(aid) OVER w, > > count(*) OVER w > > FROM pgbench_accounts > > WINDOW w AS ( > > PARTITION BY bid > > ORDER BY aid > > ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING > > AFTER MATCH SKIP PAST LAST ROW > > INITIAL > > PATTERN (START UP+) > > DEFINE > > START AS TRUE, > > UP AS aid > PREV(aid) > > ); > > I ran this against your patch. It failed around > 60k rows. Nice, that's actually more frames than I expected. Looks like I have similar results here with my second test query (segfault at ~58k rows). Thanks, --Jacob
