Comments on: SQL SERVER – Maximum Number of Index per Table

By: madhivanan

madhivanan — Fri, 14 Oct 2011 12:50:46 +0000

the total indexes are 250 (including 1 clustered index) for 2005 and 1000 (including 1 clustered index) from version >2005. So they are 250 and 1000 in total

By: Rajesh

Rajesh — Thu, 13 Oct 2011 17:07:23 +0000

Why we have 249 non clustered index in sql server 2005? why not 240 or 300? and the same question for sql server 2008, why 999 ? Why not 800 or 1000?

By: Srinivas Kadiyala

Srinivas Kadiyala — Thu, 13 Oct 2011 11:10:53 +0000

Thanks :)

By: Josh Geake

Josh Geake — Fri, 15 Jul 2011 13:17:43 +0000

As ever Pinal, you’re so helpful!

Thanks a lot, Josh.

By: SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 14 of 31 Journey to SQLAuthority

Thu, 14 Jul 2011 01:31:45 +0000

[...] 1 Clustered Index + 999 Nonclustered Index = 1000 Index. (Read more here) [...]

By: SQL SERVER – Database Worst Practices – New Town and New Job and New Disasters Journey to SQLAuthority

Tue, 12 Jul 2011 01:32:53 +0000

[...] As a fact, we all know that a set of data can be only stored in only one order; that is why only one clustered index is possible.(Read more here) [...]

By: Gennadiy Chornenkyy

Gennadiy Chornenkyy — Mon, 17 Jan 2011 18:19:24 +0000

Looks like yes – if you try to create index on table with max number of statistics you’ll get en error message

By: Yogesh Goswami

Yogesh Goswami — Fri, 18 Jun 2010 10:09:51 +0000

Well we can have a unique index. You just need to use Unique key word in Create Index statement.
/*Sample script*/
Use tempdb

Create table test1 (col1 int, col2 int)
Create unique index idx_uni1 on test1(col1)

So in short, an index could be clustered and non-clustered as well as unique and non-unique(total 4 variations). A unique index will not allow duplicate entry in the table based on the index key columns.
By default any index is non-cluster and non-unique unless specified otherwise in create statement.

By: hennie

hennie — Wed, 07 Apr 2010 08:27:05 +0000

Two questions:

* What’s the number of indexes in SQL Server 2000 ?
* Do statistics occupy ’slots’ of this number. In other words clusterd index + non clustered + statistcs = 250 (SQL 2000/SQL 2005?)

thnx!

By: hennie

hennie — Wed, 07 Apr 2010 08:26:21 +0000

Two questions:

* What’s the number of indexes in SQL Server ?
* Do statistics occupy ‘slots’ of this number. In other words clusterd index + non clustered + statistcs = 250 (SQL 2000/SQL 2005?)

By: Imran Mohammed

Imran Mohammed — Sat, 27 Mar 2010 21:07:42 +0000

Cluster Index Physically Stores data, or arranges data in one order (depends on which column(s) you have defined Clustered index and in which order.

As a fact we all know that set of data can be only stored in only one order, that is why only one clustered index is possible.

You can create a view on top of table and then you can created Clustered index on that view.

Hope this helps.
~ IM.

By: Aniket Bhoyar

Aniket Bhoyar — Sat, 27 Mar 2010 08:59:55 +0000

Why can there be only 1 clustered index and not more than 1?

By: Harish Sharma

Harish Sharma — Fri, 12 Feb 2010 10:18:44 +0000

Good information. Thanks Pinal for sharing. Keep posting.

By: Nitin Sharma

Nitin Sharma — Tue, 02 Feb 2010 06:59:26 +0000

Very Informative..!

By: kailash Dhanke

kailash Dhanke — Wed, 20 Jan 2010 07:34:37 +0000

In SQL 2005

1 Cluster Index
249 Non Cluster Index

Total 250
———————————–
In SQL 2008

1 Cluster Index
999 Non Cluster Index

Total
1000

By: Kalyan Kumar Navana

Kalyan Kumar Navana — Fri, 25 Sep 2009 13:16:38 +0000

There are 2 types of indexes
1. Clustered Indexes
2. Non-clustered Indexes

There can be only one Clustered index in a table
and there can be 249 non-clustered indexes on a table

By: Imran Mohammed

Imran Mohammed — Fri, 18 Sep 2009 03:04:46 +0000

@Darshan,

There are no unique indexes in any version of SQL Server.

There are basically two types of indexes.
Clustered Indexes and Non-Clustered Indexes.

In SQL Server 2005 :
you can have
1 Clustered Index on a table and
249 Non Clustered Indexes.

Reference: Books Online

Follow this link :
http://www.sql-server-helper.com/sql-server-2005/maximum-capacity-specifications.aspx

But, When ever you create a unique constraint on a column in a table, it automatically creates a non-clustered indexes.

A unique Key constraint cannot be created with out an index, either the index could be Clustered or Non-Clustered.

So your question could be, How many unique constraints you can have on a table or how many Non-Clustered indexes you can have on a table.

Answer is 249. (Given, no other Non-Clustered index is created Separately)

~ IM.

By: Darshan

Darshan — Thu, 17 Sep 2009 19:52:43 +0000

Can you tell me what’s the maximum number of unique indexes in a table in sql server 2005 ?

By: Darth Sonic

Darth Sonic — Tue, 11 Aug 2009 10:07:15 +0000

@Vijay: You are using SQL Server 2005, right? Read the post above or: http://msdn.microsoft.com/en-us/library/ms143432(SQL.90).aspx

By: Vijay

Vijay — Tue, 11 Aug 2009 06:47:38 +0000

Hi Friends,

Can any one tell me why we cannot create more than 249 Non-Clustered Indexes??

Thanks in advance,
Vijay Vasudevan

By: pinaldave

pinaldave — Mon, 29 Jun 2009 13:51:54 +0000

Thank you Imran and everybody.

Error has been fixed.

Kind Regards,
Pinal

By: Darth Sonic

Darth Sonic — Mon, 29 Jun 2009 12:07:56 +0000

A little fault in your addition:
1 Clustered Index + 999 Nonclustered Index = 250 Index

Must be 1000 Index ;-)

By: John

John — Mon, 29 Jun 2009 10:44:51 +0000

Your total for SQL2008 isn’t right either (1+999 = 1000).

Of course the likelihood is that any table that hits the maximum limits is part of a bad design. Can anyone think of any scenario where even 250 nonclustered indexes might be necessary?

By: Deepak

Deepak — Mon, 29 Jun 2009 10:32:54 +0000

Yes, Imran is right. The link for SQL Server 2005 is referred to SQL Server 2000.

Also I am little confused for SQL Server 2008 as it shows
1 Clustered Index + 999 Nonclustered Index = 250 Index

Is it not 1000 Index?

Thanks,
DV

By: Artiom

Artiom — Mon, 29 Jun 2009 09:26:03 +0000

I suppose you meant 100 indexes for SQL 2008 :)