----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Subqueries: Inside-out execution for non-semijoin materialized subqueries that are AND-parts of the WHERE CREATION DATE..: Sun, 28 Feb 2010, 14:02 SUPERVISOR.....: Monty IMPLEMENTOR....: COPIES TO......: Igor, Psergey, Timour CATEGORY.......: Server-RawIdeaBin TASK ID........: 92 (http://askmonty.org/worklog/?tid=92) VERSION........: WorkLog-3.4 STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: -=-=(Psergey - Sun, 28 Feb 2010, 14:03)=-=- Observers changed: Psergey,Igor,Timour DESCRIPTION: Consider the following case: SELECT * FROM big_table WHERE oe IN (SELECT ie FROM table_with_few_groups WHERE ... GROUP BY group_col) AND ... Here the best way to execute the query is: Materialize the subquery; # now run the join: for each record R1 in materialized table for each record R2 in big_table such that oe=R1 pass R2 to output Semi-join materialization supports such strategy with SJM-Scan strategy. This WL entry is about adding support for such strategies for non-semijoin subqueries. ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)