Solved

SQL 2005 Composite Index vs Non Composite Index

Posted on 2010-09-08
4
364 Views
Last Modified: 2012-05-10
I have been told not to create composite index's over tables.
If I have a table and create a composite index over Cust#, Invoice# and Date,
I was told that it is better to create 3 index's one over Cust#, one over Invoice# and one over Date.

Any truth to this ?

What is best way ?
0
Comment
Question by:thayduck
  • 2
4 Comments
 
LVL 60

Expert Comment

by:chapmandew
ID: 33627070
The honest truth is...it depends!

Depends on the queries and the usage.  THE query optimizer can intersect indexes, so seperate queries will often show benefit.  However, in terms of bookmark lookups...you need the columns in the same NC index.  

Clear as mud?  :)
0
 
LVL 142

Accepted Solution

by:
Guy Hengel [angelIII / a3] earned 25 total points
ID: 33627091
the answer is: it depends on the queries you run against the table.composite indexes can be helpful, if most queries have more than 1 condition in the where clause for this table.usually, you search in the invoices either by invoice# , or by cust#, but normally not by both at the same time.however, cust# and date might be specified together, so a composite index on cust + date is not "bad".
0
 
LVL 57

Expert Comment

by:Raja Jegan R
ID: 33627095
As mentioned above, it depends..
Its recommended to keep the index size smaller and hence you need to be more careful when adding more and more columns to your indexes.
0
 
LVL 60

Assisted Solution

by:chapmandew
chapmandew earned 25 total points
ID: 33627125
>>Its recommended to keep the index size smaller and hence you need to be more careful when adding more and more columns to your indexes.

From a disk space point of view, having 3 indexes is going to be larger than 1 3-column index.  In the case w/ the 3 indexes, each index has the clustered key contained in the NC.
0

Featured Post

NAS Cloud Backup Strategies

This article explains backup scenarios when using network storage. We review the so-called “3-2-1 strategy” and summarize the methods you can use to send NAS data to the cloud

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

There are some very powerful Data Management Views (DMV's) introduced with SQL 2005. The two in particular that we are going to discuss are sys.dm_db_index_usage_stats and sys.dm_db_index_operational_stats.   Recently, I was involved in a discu…
In this article I will describe the Copy Database Wizard method as one possible migration process and I will add the extra tasks needed for an upgrade when and where is applied so it will cover all.
Get a first impression of how PRTG looks and learn how it works.   This video is a short introduction to PRTG, as an initial overview or as a quick start for new PRTG users.
This is a video that shows how the OnPage alerts system integrates into ConnectWise, how a trigger is set, how a page is sent via the trigger, and how the SENT, DELIVERED, READ & REPLIED receipts get entered into the internal tab of the ConnectWise …

919 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

16 Experts available now in Live!

Get 1:1 Help Now