Re: [ADMIN] Q: Structured index - which one runs faster?

Vivek Khera <khera@kcilink.com>

From: Vivek Khera <khera@kcilink.com>
To: pgsql-general@postgresql.org
Date: 2003-05-23T15:09:00Z
Lists: pgsql-performance
A related question:

Are any of these indexes redundant:

 CREATE UNIQUE INDEX user_list_id_email ON user_list (owner_id,user_email);
 CREATE INDEX user_list_owner_id ON user_list (owner_id);
 CREATE INDEX user_list_oid_created ON user_list (owner_id,user_created);

In particular, is user_list_owner_id redundant to
user_list_oid_created?  Will the latter be used for queries such as

 SELECT user_fname from user_list where owner_id=34

If so, I can drop the owner_id index.  the _id columns are integers,
created is a datetime, and email is a string.  owner_id is also a
foreign key into the owners table (via REFERENCES), if that matters.

I'd try it out by dropping the index, but reindexing it takes a *LONG*
time which I cannot afford to be unavailable.

Thanks.

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Vivek Khera, Ph.D.                Khera Communications, Inc.
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