> On Sat, Oct 21, 2023 at 7:39 PM Tatsuo Ishii <is...@sraoss.co.jp> wrote: >> Attached is the v10 patch. This version enhances the performance of >> pattern matching. > > Nice! I've attached a couple of more stressful tests (window > partitions of 1000 rows each). Beware that the second one runs my > desktop out of memory fairly quickly with the v10 implementation. > > I was able to carve out some time this week to implement a very basic > recursive NFA, which handles both the + and * qualifiers (attached).
Great. I will look into this. > It's not production quality -- a frame on the call stack for every row > isn't going to work Yeah. > -- but with only those two features, it's pretty > tiny, and it's able to run the new stress tests with no issue. If I > continue to have time, I hope to keep updating this parallel > implementation as you add features to the StringSet implementation, > and we can see how it evolves. I expect that alternation and grouping > will ratchet up the complexity. Sounds like a plan. By the way, I tested my patch (v10) to handle more large data set and tried to following query with pgbench database. On my laptop it works with 100k rows pgbench_accounts table but with beyond the number I got OOM killer. I would like to enhance this in the next patch. 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) ); Best reagards, -- Tatsuo Ishii SRA OSS LLC English: http://www.sraoss.co.jp/index_en/ Japanese:http://www.sraoss.co.jp
