The key scalability features in SQL Server 2008 database engine include: ■ ■ Partitioning Segmenting of data in large tables and indexes into units that can be distributed across multip
Trang 1The key database engine features in the Enterprise Edition address scalability,
high availability, and security
Scalability is the ability to add more resources In SQL Server 2008 Enterprise
Edition, this is achieved by scaling up servers by adding additional CPUs, memory,
or disks to a single server or by scaling out by moving certain services or databases
to other servers
The key scalability features in SQL Server 2008 database engine include:
■
■ Partitioning Segmenting of data in large tables and indexes into units
that can be distributed across multiple filegroups in a database to improve
IO performance Partitioning is very useful in improving the performance
of very large OLTP and data-warehousing databases
■
■ Data compression Reduces the size of tables, indexes, or partitions,
thereby reducing the database disk requirements
■
■ Resource governor Provides control over the amount of CPU and
memory allocated to SQL Server 2008 workloads without any application
changes
■
■ Partition table parallelism Improves the query processing performance
on partitioned tables for parallel queries by enhancing the partitioning
information in the compile-time and runtime execution plans
■
■ Multi-instance support Establishes the maximum number of SQL
Server 2008 instances that can be created on a server Enterprise Edition
supports up to 50 instances on a server, Compact Edition only supports
one instance, and all the other editions support up to 16 instances
■
■ Log shipping Allows you to automatically send transaction log backups
from a primary database on a primary server instance to one or more
secondary databases on separate secondary server instances Log shipping
supports the high availability option of database mirroring The Express
and Mobile editions do not support this feature
■
■ Replication Enables a primary database server to distribute data to one or
more secondary servers
Partitioning, data compression, and partition table parallelism are exclusive to
the SQL Server 2008 Enterprise Edition Also note that some replication features
are very limited or not available in the Standard Edition
Trang 2High availability refers to the availability of system resources when a component
in the system fails Please note that both log shipping and replication are considered
as features of availability as well as scalability The high availability features only available in the Enterprise Edition include:
■
■ Database snapshots Provide a read-only static version of a source
database on the same database instance One of the many uses of database snapshots is creating separate databases for reporting that are separate from online transactions
■
■ Fast recovery Allows users access the database while the database is rolling
back uncommitted transactions Only the uncommitted transactions during the crash are locked till the rollback of the transaction is complete
■
■ Online indexing Allows index maintenance operations to be performed
while the database is online and active
■
■ Online restore Enables the restoring of backup files using multiple
filegroups while the database is still online
■
■ Mirrored backups Add redundancy of backup media, thereby increasing
backup reliability
■
■ Backup compression Provides smaller backup files, thereby reducing
disk space resources
■
■ Hot Add Memory and CPU Provide the ability to add memory or
New & Noteworthy…
Partition-Aware Seek Operation
Query performance on partitioned tables is significantly enhanced in SQL Server 2008 Enterprise Edition.
In SQL Server 2008 partitioned tables are treated like tables with an index on the partition ID column This allows the creation and management
of simpler query plans and improved performance by using the partition’s column and function.
Trang 3In the area of security, the Enterprise Edition is the only edition that supports
SQL Server auditing and transparent database encryption SQL Server auditing
provides a simpler mechanism using T-SQL to trigger, store, and view audits
An example of an audit implementation is to track log-on activity of specific user
accounts or groups Transparent database encryption (TDE) encrypts the database
data and log files, meeting the regulatory or corporate data security standards
without requiring application changes
In terms of replication, the Enterprise Edition supports Oracle publishing and
peer to peer (P2P) transactional replication Oracle publishing allows an Oracle
database to transmit data via replication to a SQL Server instance P2P transactional
replication provides copies of data that are transaction consistent in near real-time
to all servers participating in the replication topology scheme
Integration Services in SQL Server 2008, provided in the Enterprise and
Standard Editions, have the most of the Integration Services features, while the
other editions have very limited features as noted in Table 2.2
Integration Services
Feature Enterprise Standard Workgroup Web Express
SQL Server Import
and Export Wizard
with basic sources
and destinations and
Execute SQL task
Integration Services
Integration Services
API and object model Yes Yes Yes Yes
Integration Services
service, wizards, and
command-line utilities
Basic tasks and
transformations Yes Yes
Log providers
Data profiling tools Yes Yes
Table 2.2 SQL Server 2008 Integration Services Features by Edition
Continued
Trang 4Integration Services
Feature Enterprise Standard Workgroup Web Express Additional sources
and destinations:
Raw File source
■
■
XML source
■
■
DataReader
■
■
destination
Raw File
■
■
destination
Recordset
■
■
destination
SQL Server Compact
■
■
destination
SQL Server
■
■
destination
Advanced sources,
transformations,
and destinations:
Data Mining Query
■
■
transformation
Fuzzy Lookup and
■
■
Fuzzy
Grouping
■
■
transformations
Term Extraction
■
■
and Term Lookup
transformations
Data Mining
■
■
Model Training
destination
Dimension
■
■
Processing
destination
Partition Processing
■
■
destination
Yes
Table 2.2 Continued SQL Server 2008 Integration Services
Features by Edition
Trang 5Table 2.3 lists the key Analysis Services features between the Enterprise and
Standard Editions in the area of Data Warehouse creation, scale and performance,
multidimensional analytics, and data mining Analysis Services is not available in
the Workgroup, Web, Express, and Compact Editions
Data Warehouse
Creation Create cubes without a database Yes Yes
Auto-generate staging and data warehouse schema Yes Yes Attribute relationship designer Yes Yes Efficient aggregation designers Yes Yes
Data Warehouse
Scale and
Performance
Change data capture Yes Star join query optimization Yes Scalable read-only
AS configuration Yes Proactive caching Yes Auto parallel partition
Partitioned cubes Yes Distributed partitioned cubes Yes
Multidimensional
Analytics SQL Server Analysis Services service Yes Yes
SQL Server Analysis Services
General performance/scale
Table 2.3 SQL Server 2008 Analysis Services Features by Edition
Continued