----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Better choice between range and index_merge/intersection options CREATION DATE..: Wed, 27 May 2009, 15:20 SUPERVISOR.....: Monty IMPLEMENTOR....: Psergey COPIES TO......: CATEGORY.......: Server-RawIdeaBin TASK ID........: 26 (http://askmonty.org/worklog/?tid=26) VERSION........: Server-9.x STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: DESCRIPTION: The optimizer does a cost-based choice between possible range and index_merge/intersection scans. There are some issues with it: - index_merge/intersection gets chosen even when there is a single multi-part index that covers all keys. Measurements show that this is a poor choice. - The picked index_merge/intersection can use a redundant set of indexes: it will be intersect(idx1, ..., idxN) where all columns in idxN are covered by other used indexes. This WL is to fix these limitations. ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)