From: Johan De Meersman Date: March 31 2011 6:20pm Subject: Re: A common request List-Archive: http://lists.mysql.com/mysql/224740 Message-Id: <60f09b80-e912-4537-af10-44eb3d671c06@zimbra> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit ----- Original Message ----- > From: "mos" > > The IN() clause is very inefficient because MySQL will NOT use the > index. > It will have to traverse the entire table looking for these values. Has that still not been remedied ? > It will get the information from the index and not have to access the > record data from disk. If the index is stored in memory, then it > won't have to go to disk (unless you also have a sort). That is why the query > cache is so important. Indices don't go in the query cache, strictly speaking, they go in the MyISAM index cache or in the InnoDB pool. -- Bier met grenadyn Is als mosterd by den wyn Sy die't drinkt, is eene kwezel Hy die't drinkt, is ras een ezel