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Chapter 4: Client Connectivity
4
Accessing Diagnostic Information in the Extended Events Log
Another new feature in SNAC 11 is that data access tracing has been updated to make it
easier to get diagnostic information about connection failures from the connectivity ring
buffer and application performance information from the extended events log. Using data
access tracing is outside the scope of this book, but if you would like to learn more about
this feature, check out this technical article from Microsoft: http://msdn.microsoft
.com/en-us/library/cc765421(SQL.100).aspx.In SQL Server 2012, connection operations via the SQL Server Native Client will generate
a client connection ID. If connectivity fails, you can access the connectivity ring buffer
and fi nd the ClientConnectionID fi eld to get diagnostic information about the ses-
sion and the connection failure. For more detailed examples on how you can leverage this
feature, see the Technet article: http://technet.microsoft.com/en-us/library/
hh213095.Data access tracing is intended only for troubleshooting and diagnostic purposes and may not be suitable for
auditing or security purposes.ODBC Features
With SQL Server 2012, Microsoft has made a radical shift on its stance with regard to ODBC.
As of this release, they have decided to push ODBC as the primary method of connectivity
and will be deprecating OLEDB in future releases, although it’s still available in SQL 2012. In
this release, the SQL Server Native Client OLE DB provider is the fi rst of the OLE DB provid-
ers that will be deprecated and will not be available in the next release of SQL Server; how-
ever, it will be supported for the life cycle of SQL Server 2012.As for the ODBC provider itself, three new features were added to the ODBC support, which
were also added to the standard ODBC in the Windows 7 SDK:■ (^) Asynchronous execution on connection-related operations
■ (^) C Data Type Extensibility
■ (^) Calling SQLGetData with a small buffer multiple times to retrieve a large
parameter value
Multiple Active Result Sets (MARS)
SQL Server 2012 provides support for having multiple active SQL statements on the same
connection. This capability includes being able to interleave reading from multiple result
sets and being able to execute additional commands while a result set is open.
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