From: Eric Savage
Date: March 26 1999 6:27am
Subject: Indexing
List-Archive: http://lists.mysql.com/mysql/992
Message-Id: <199903260627.BAA15815@mail.hotpop.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit

We run an email account management system with mysql.  We use multiple
domains, so our main user table has a unique index on the user/domain
fields.  However, I do alot of work with just the user field.  Should I
create another non-unique index on just the user field, or would this
provide no/worse performance?  This is a varchar(21) field and alot of
substring searches are done.