Range partition ordering for ORDER BY LIMIT queries

[Nikos Sarkas]

Hello,

Suppose that I perform range partition on a column `date'. Consider now a query

SELECT *
FROM table
WHERE date<=20110127 ORDER BY date DESC LIMIT 1

A possible optimization in this case would be to consider the matching partitions in descending order of date upper bounds and stop early. Does this optimization happen? Does it depend on whether `date' is part of the primary key? If the optimization doesn't happen, is there a well defined order that the partitions will be considered (i.e., lexicographically)?

Thank you,
Nikos