On 04/01/13 21:05, OQ wrote:
> On Fri, Jan 4, 2013 at 1:55 PM, Aaron Halfaker <[email protected]> 
> wrote:
>> Hello,
>>
>> I've been working on a new script that will access the MySQL database.  In
>> testing this script, I was worried about the complexity of some of my
>> queries, so I naturally went to the MySQL client and ran them with
>> "explain".  It appears that I do not have permission to do so.  Is this
>> intended?  Is something wrong?
> 
> EXPLAIN can leak information from underlying tables, so if you dont
> have permissions for those tables the explain will fail with the error
> message provided.

It was possible until the last mysql update. And yes, being able to
EXPLAIN queries is *very* useful. Otherwise the already-a-guessing-game
of making efficient queries is even harder.

I don't think an EXPLAIN can leak information not already available to
us by querying the view (possibly multiple times).

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