From: Aaron Blew (aaronblewgmail.com)
Date: Fri Sep 05 2008 - 16:34:02 CDT

• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

We'd need more information on what the where clauses of the queries
look like to assist with this.

-Aaron

On 9/5/08, Krishna Chandra Prajapati <prajapatikcgmail.com> wrote:
> 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 <ewen.fortunegmail.com> 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
>> <prajapatikcgmail.com> 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
>

--
Sent from my mobile device

--
MySQL General Mailing List
For list archives: http://lists.mysql.com/mysql

• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]