Mark Williams <mark.williams@jivesoftware.com> wrote:
> If I re-write the query like this:
>
> explain SELECT messageID FROM Message WHERE modificationDate >=
> 1302627793988 ORDER BY modificationDate LIMIT 1;
> I also get a better plan.
Yeah, but it's not necessarily the same value. Do you want the
minimum messageID where modificationDate >= 1302627793988 or do you
want the messageID of some row (possibly of many) with the minimum
modificationDate where modificationDate >= 1302627793988?
Since you're asking for a logically different value with that query,
it's not surprising it uses a different plan.
-Kevin