Whoops,
I meant this query (ordering my messageid):
SELECT messageID FROM Message WHERE modificationDate>= 1302627793988 ORDER BY messageID LIMIT 1;
Sometimes this gives the better plan. But not always.
On 04/15/2011 11:13 AM, Kevin Grittner wrote:
Mark Williams<mark.williams@xxxxxxxxxxxxxxxx> 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
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