…: mysql> explain select * from rnd order by r desc limit 1 \G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: rnd type… badly. Too bad –min-examined-row-limit is not yet implemented EXPLAIN would also return misleading number of rows for queries of the type: SELECT … FROM TBL WHERE KEY_PART1=CONST ORDER BY KEY_PART2 LIMIT…

… exhaust the query in order to determine how many rows it COULD have returned, had you asked for all of them. 2… from a selectivity standpoint, if your limit clause is small relative to the size of your return set, you’ll get out… limit. e.g. if a query returns 100,000 rows order by timestamp limit 99990, 10 is MUCH slower than order by timestamp desc limit…

… think query is simple if it returns few rows while what really matters is amount of rows are analyzed by the query. For… Queries – SELECT name,descr FROM titles ORDER BY rank DESC LIMIT 10 – If there is no proper index and query has… on rank column maxes this query to use 10 rows to return 10 rows – exactly what we’re looking for. However our COUNT…