Feature Requests item #1737438, was opened at 2007-06-14 19:45 Message generated for change (Comment added) made by nielsnes You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=482471&aid=1737438&group_id=56967
Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. >Category: MonetDB - GDK Group: None >Status: Closed Priority: 5 Private: No Submitted By: Martin Kersten (mlkersten) >Assigned to: Niels Nes (nielsnes) Summary: GDK: kintersect performance issue Initial Comment: One of the active users reported unexpected performance problems on SQL queries involving IN predicates, e.g. ... WHERE attr IN (1,2,3) Analysis of the trace uncovered an area that deserves attention. The semijoin produced by the SQL frontend involved a large left BAT (13Mrows) and against a BAT with the constants. The algorithm went to the default kintersect. A test-case to illustrate the inbalance in performance is added under the name src/mal/Tests/venks.mal Timing large operand is 1M, small 2 elements type :bat[:oid,:sht] #kintersect(largeRev,smallRev) 51356 #count 61 #join(large,smallRev) 103289 #count 61 #kintersect(smallRev,largeRev) 33 #count 3 #join(small,largeRev) 37 #count 3 ---------------------------------------------------------------------- >Comment By: Niels Nes (nielsnes) Date: 2007-12-11 21:40 Message: Logged In: YES user_id=43556 Originator: NO we now also handle this case efficiently. We use a direct hashing approach. ---------------------------------------------------------------------- Comment By: Martin Kersten (mlkersten) Date: 2007-11-10 22:33 Message: Logged In: YES user_id=490798 Originator: YES files exist.. remainder is not a bug but a performance feature request. ---------------------------------------------------------------------- Comment By: Stefan Manegold (stmane) Date: 2007-06-20 18:06 Message: Logged In: YES user_id=572415 Originator: NO The respective test case fails due to missing stable output: http://monetdb.cwi.nl/testing/projects/monetdb/Current/MonetDB5/.mTests103/GNU.64.64.d-Fedora6/src_mal/venks.out.00.html http://monetdb.cwi.nl/testing/projects/monetdb/Current/MonetDB5/.mTests103/GNU.64.64.d-Fedora6/src_mal/venks.err.00.html ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=482471&aid=1737438&group_id=56967 ------------------------------------------------------------------------- SF.Net email is sponsored by: Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ Monetdb-bugs mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/monetdb-bugs
