Hi, What would you say about the below table . What can i do to make it more efficient.
CREATE TABLE mailer_student_status ( student_id decimal(22,0) NOT NULL default '0', param varchar(128) NOT NULL default '', value varchar(128) default NULL, PRIMARY KEY (student_id,param). KEY idx_value (value) ) On Sat, Sep 6, 2008 at 1:16 AM, ewen fortune <[EMAIL PROTECTED]> wrote: > Hi, > > Following on from what Mike mentioned, indexing all columns does not > really help as MySQL will at most use one index for a query, so its > important to pick your indexes carefully and consider constructing > composite indexes. An index on a single column may not even be used > due to poor cardinality. > > Ewen > > On Fri, Sep 5, 2008 at 9:27 PM, Krishna Chandra Prajapati > <[EMAIL PROTECTED]> wrote: > > Hi all, > > > > I am looking for, is there any specific reason for not indexing all > columns > > of a table. whats the impact on the performance. Although indexing is > meant > > for getting great performance. So, why indexing all columns is not > > feasible. (Read in docs that all columns should not be indexed) > > > > -- > > Krishna Chandra Prajapati > > > -- Krishna Chandra Prajapati
