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Some factors alone might be enough for you to decisively choose one strategy over
another. Regardless of what strategy you select, do not forget testing and validation.
Even if you select an in-place upgrade strategy, test the upgrade process and results on
a separate server first. For more testing information, see the "Test the Upgrade Plan"
section later in this chapter.
Backward Compatibility
When planning for an upgrade to SQL Server 2012, you have to understand what
features are deprecated, discontinued, or changed in the new version. Being aware of
these changes beforehand can help you prevent both performance problems and
issues related to making the application available.
Generally, SQL Server 2012 is backward compatible with SQL Server 2005/2008/20008
R2. However, you should examine some feature changes during the planning process.
The most serious backward-compatibility issues that will affect planning are those that
will block an in-place upgrade and prevent an installation of SQL Server 2012. If the
SQL Server 2012 Setup program detects these issues during an in-place upgrade, it will
exit the installation, leaving the legacy instance unchanged. The SQL Server 2012
Upgrade Advisor is the best tool for finding these kinds of blocking issues beforehand.
Chances are good that you will encounter only a few issues, if any.
In the component- and feature-specific chapters in this document, you can review the
relevant details for each of these categories. For more information, see
SQL Server
Backward Compatibility
(http://technet.microsoft.com/en-
us/library/cc707787(SQL.110).aspx ) in SQL Server 2012 Books Online.
Note: The most serious backward-compatibility issues that will affect your planning
are those that will block an in-place upgrade and prevent the installation of SQL
Server 2012. If the SQL Server 2012 Setup program detects these issues during an
in-place upgrade, it will exit the installation, leaving the legacy instance unchanged.
You must resolve the blocking issues to continue.
Deprecated Features
Features that are deprecated in SQL Server 2012 still operate the same as in the legacy
versions. However, they will be removed in the next version of SQL Server. Access to
these features does not necessarily have to be removed to complete an upgrade.
However, you should eventually address them because they could cause problems with
upgrades after SQL Server 2012. For more information, see
Deprecated SQL Server
Features in SQL Server 2012
(http://msdn.microsoft.com/en-
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SQL Server 2012 Upgrade Technical Guide
us/library/cc707789(v=sql.110).aspx) in SQL Server 2012 Books Online. Also see
"System Monitor—SQL Server: Deprecated Features Object" in the “Upgrade Tools”
section later in this chapter.
Note: An upgrade will not be blocked if you use deprecated features. However, it is
advised that you decide how or when you want to deal with any of these to give
yourself sufficient time to resolve the issues before they are discontinued in some
future SQL Server release.
Discontinued Features
In any component of SQL Server 2012, some features of earlier SQL Server versions
may have been discontinued. These features functioned in earlier versions of SQL
Server but were removed from SQL Server 2012. Although some references to these
features might not block an in-place upgrade, you should remove those references
anyway. If the reference is not removed, the application might not behave correctly.
Use Upgrade Advisor to detect whether your application is using discontinued features.
For more information about such features, see
Discontinued SQL Server Features in
SQL Server 2012
(http://msdn.microsoft.com/en-us/library/cc707782(v=sql.110).aspx) in
SQL Server 2012 Books Online.
Breaking Changes
Breaking changes to SQL Server 2012 are those that might require changes to the
applications because the features in question now have a different behavior. If you do
not use the feature, there is no effect on you. However, if you do use the feature, your
application might be affected. The best tool for discovering this kind of issue is
Upgrade Advisor, which analyzes a legacy system and reports on all potential breaking
changes and how to address them. For more information about this kind of change, see
Breaking Changes to SQL Server Features in SQL Server 2012
(http://msdn.microsoft.com/en-us/library/cc707784(v=sql.110).aspx) in SQL Server 2012
Books Online.
Behavior Changes
Behavior changes might not visibly affect your database code or applications. However,
you have to be aware of them because the interpretation might be different. For
example, the behavior of the SQL Server Native Client changes from SQL Server 2005 to
SQL Server 2012. For more information, see
Behavior Changes to SQL Server Features
in SQL Server 2012
(http://msdn.microsoft.com/en-us/library/cc707785(v=sql.110).aspx)
in SQL Server 2012 Books Online.
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SQL Server 2012 Upgrade Technical Guide
Upgrade Tools
We have talked about the value of the SQL Server 2012 Upgrade Advisor several times
already in this chapter. Some other tools are also available to help automate the
upgrade process to SQL Server 2012. Each tool has its own purpose and timing, so it is
best to become familiar with all the tools and then use those most appropriate to each
upgrade project.
SQL Server 2012 Upgrade Advisor
Perhaps the most important tool of the tools typically used for upgrade planning is
Upgrade Advisor. Upgrade Advisor smoothes the transition to SQL Server 2012 by
predicting issues in your legacy instances of SQL Server. It analyzes objects and code
within legacy instances and produces reports detailing upgrade issues, if there are any,
organized by SQL Server component. The resulting reports show detected issues and
provide guidance about how to fix the issues or work around them. The reports are
stored on disk, and you can review them by using Upgrade Advisor or export them to
Microsoft Excel for further analysis.
In addition to analyzing data and database objects, Upgrade Advisor can analyze
Transact-SQL (T-SQL) scripts and SQL Server Profiler/SQL Trace traces. Upgrade Advisor
examines SQL code for syntax that is no longer valid in SQL Server 2012. It generates a
report listing the code in question, together with links to where you can find more
information to help resolve the questionable code. For information about how to
upgrade T-SQL queries, stored procedures, scripts, and application code, see Chapter
10, "Transact-SQL Queries."
Requirements for running Upgrade Advisor are as follows:
Windows Vista SP1, Windows 7, or Window Server 2008 R2
The Microsoft .NET Framework 4 (the same version of the .NET Framework
included with SQL Server 2012 and Visual Studio 2010)
Windows Installer 4.5
Pentium III-compatible processor or a later version, with a processor speed of at
least 500 MHz
15 MB of available hard disk space
Whether you choose an in-place upgrade or a side-by-side upgrade, run Upgrade
Advisor on your legacy systems. You can run Upgrade Advisor from a local or remote
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