Maximum Capacity Specifications for SQL Server 2000 and SQL Server 2005

The following table specifies the maximum sizes and numbers of various objects defined in SQL Server 2000/2005 databases or referenced in Transact-SQL statements. The table does not include Microsoft SQL Server 2000 Windows CE Edition and Microsoft SQL Server 2005 Windows CE Edition.
1 Network Packet Size is the size of the tabular data stream (TDS) packets used to communicate between applications and the relational Database Engine. The default packet size is 4 kilobytes (KB), and is controlled by the network packet size configuration option.

2 The maximum number of bytes in any index key cannot exceed 900 in SQL Server 2005. You can define a key using variable-length columns whose maximum sizes add up to more than 900, provided no row is ever inserted with more than 900 bytes of data in those columns. In SQL Server 2005, you can include nonkey columns in a nonclustered index to avoid the maximum index key size of 900 bytes.

3 Database objects include objects such as tables, views, stored procedures,user-defined functions, triggers, rules, defaults, and constraints.The sum of the number of all objects in a database cannot exceed 2,147,483,647.

4 Although a table can contain an unlimited number of FOREIGN KEY constraints, the recommended maximum is 253. Depending on the hardware configuration hosting SQL Server, specifying additional foreign key constraints may be expensive for the query optimizer to process.

5 This value is for static lock llocation. Dynamic locks are limited only by memory.

6 If a stored procedure accesses more than 8 databases, or more than 2 databases in interleaving, you will receive an error.

7 If the table contains one or more XML indexes, the clustering key of the user table is limited to 15 columns because the XML column is added to the clustering key of the primary XML index. In SQL Server 2005, you can include nonkey columns in a nonclustered index to avoid the limitation of a maximum of 16 key columns.

8 SQL Server 2005 supports row-overflow storage which enables variable length columns to be pushed off-row. Only a 24-byte root is stored in the main record for variable length columns pushed out of row; because of this, the effective row limit is higher than in previous
releases of SQL Server. SQL Server 2005 Books Online.


References:
SQL Server 2005 Books Online

Introduction of SQL Server Integration Services in SQL Server 2005

SQL Server took a leap forward in database maintenance functionality with the introduction of SSIS (SQL Server Integration Services) in SQL Server 2005. The SQL Server Development Team at Microsoft adapted SSIS to offer point-and-click database maintenance, offering vast improvements over DTS (Database Transformation Services) and SQLMaint in SQL Server 2000. The Database Maintenance Wizard still exists to build the initial process, but the modifications are all made to an SSIS package stored locally on the server. Compared to the SQLMaint black box, the new interface will be easier to understand and less intimidating for DBAs. Therefore, database maintenance will be conducted on a more regular basis and overall performance will improve; a little SQL Server care and attention can go along way in improving performance.
That is not to say that DBAs following sophisticated maintenance regimens should abandon them; they should just leverage SSIS' new functionality to simplify the maintenance process. I wholeheartedly praise database administrators who have built such maintenance plans, but I have also worked with DBAs who have no procedures in place. I believe the SSIS interface offers a key stepping stone toward performing regularly scheduled maintenance.In turn, this plan should ensure that overall SQL Server performance is at a consistently high level to suit the organization.