sql/opt_range.cc のいろんなところに出てくる "ROR" は Ruby On Rails の略ではありません。
00453 /*
http://dev.mysql.com/sources/doxygen/mysql-5.1/opt__range_8h-source.html#00454
00454 Rowid-Ordered Retrieval (ROR) index intersection quick select.
00455 This quick select produces intersection of row sequences returned
00456 by several QUICK_RANGE_SELECTs it "merges".
00457
00458 All merged QUICK_RANGE_SELECTs must return rowids in rowid order.
00459 QUICK_ROR_INTERSECT_SELECT will return rows in rowid order, too.
00460
00461 All merged quick selects retrieve {rowid, covered_fields} tuples (not full
00462 table records).
00463 QUICK_ROR_INTERSECT_SELECT retrieves full records if it is not being used
00464 by QUICK_ROR_INTERSECT_SELECT and all merged quick selects together don't
00465 cover needed all fields.
00466
00467 If one of the merged quick selects is a Clustered PK range scan, it is
00468 used only to filter rowid sequence produced by other merged quick selects.
00469 */
00470
00471 class QUICK_ROR_INTERSECT_SELECT : public QUICK_SELECT_I
このあと external lock で got signal 6 なフローがあるんだけど、まだ調査中。
