Registry bloat after SQL Server 2012 SP1 installation

February 15th, 2013

SQL Server 2012 installation has the potential to leave an msiexec.exe installer process running after the installation finishes, as described in Windows Installer starts repeatedly after you install SQL Server 2012 SP1:

After you install SQL Server 2012 SP1 on a computer, the Windows Installer (Msiexec.exe) process is repeatedly started to repair certain assemblies. Additionally, the following events are logged in the Application log:
EventId: 1004
Source: MsiInstaller
Description: Detection of product ‘{A7037EB2-F953-4B12-B843-195F4D988DA1}’, feature ‘SQL_Tools_Ans’, Component ‘{0CECE655-2A0F-4593-AF4B-EFC31D622982}’ failed. The resource”does not exist.

EventId: 1001
Source: MsiInstaller
Description: Detection of product ‘{A7037EB2-F953-4B12-B843-195F4D988DA1}’, feature ‘SQL_Tools_Ans’ failed during request for component ‘{6E985C15-8B6D-413D-B456-4F624D9C11C2}’

When this issue occurs, you experience high CPU usage.

This issue occurs because the SQL Server 2012 components reference mismatched assemblies. This behavior causes native image generation to fail repeatedly on certain assemblies. Therefore, a repair operation is initiated on the installer package.

But the this problem has a much sinister side effect: it causes growth of the HKLM\Software registry hive. Except for the System hive, all the other registry hives are still restricted in size to a max of 2GB, see Registry Storage Space:

Views of the registry files are mapped in paged pool memory…The maximum size of a registry hive is 2 GB, except for the system hive.

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How to enable Selective XML indexes in SQL Server 2012 SP1

February 11th, 2013

SQL Server 2012 SP1 has shipped a great enhancement to XML: Selective XML Indexes. When properly used these indexes can speed up the searching of XML columns tremendously, at little disk/size cost:

The selective XML index feature lets you promote only certain paths from the XML documents to index. At index creation time, these paths are evaluated, and the nodes that they point to are shredded and stored inside a relational table in SQL Server. This feature uses an efficient mapping algorithm developed by Microsoft Research in collaboration with the SQL Server product team. This algorithm maps the XML nodes to a single relational table, and achieves exceptional performance while requiring only modest storage space.

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SQL Server backup to URL

January 25th, 2013

With the SQL Server 2012 SP1 CU2 release a new important feature was added: ability to back up and restore a database straight from Azure Blob storage:

This feature released in SQL Server 2012 SP1 CU2, enables SQL Server backup and restore directly to the Windows Azure Blob service. This feature can be used to backup SQL Server databases on an on-premises instance or an instance of SQL Server running a hosted environment such as Windows Azure Virtual Machine. Backup to cloud offers benefits such as availability, limitless geo-replicated off-site storage, and ease of migration of data to and from the cloud.

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Inside the SQL Server 2012 Columnstore Indexes

May 29th, 2012

Columnar storage has established itself as the de-facto option for Business Intelligence (BI) storage. The traditional row-oriented storage of RDBMS was designed for fast single-row oriented OLTP workloads and it has problems handling the large volume range oriented analytical processing that characterizes BI workloads. But what is columnar storage and, more specifically, how does SQL Server 2012 implement columnar storage with the new COLUMNSTORE indexes?

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Adding a nullable column can update the entire table

February 16th, 2012

In a previous article Online non-NULL with values column add in SQL Server 2012 I talked about how adding a non-null column with default values is now an online operation in SQL Server 2012 and I mentioned how the situation when the newly added column may increase the rowsize can result in the operation being performed offline:

In the case when the newly added column increases the maximum possible row size over the 8060 bytes limit the column cannot be added online.

In this article I want to show you how such a situation can arise and how it impacts even the case that prior to SQL Server 2012 was always online, namely adding a nullable column. Lets consider the following example:

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Online Index Operations for indexes containing LOB columns

August 5th, 2011

SQL Server supports online index and table rebuild operations which allow for maintenance operations to occur w/o significant downtime. While a table is being rebuild, or a new index is being built on it, the table is fully utilizable. It can be queried and any updates done to the table while the online rebuild operation is occurring will be contained in the final rebuilt table. A detailed explanation on how these online rebuild operations work can be found in the Online Indexing Operations in SQL Server 2005 white paper. But Online Index Build operations in SQL Server 2005, 2008 and 2008 R2 do not support tables that contain LOB columns, attempting to do so would trigger an error:

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How to Multicast messages with SQL Server Service Broker

July 20th, 2011

Starting with SQL Server 11 the the SEND verb has a new syntax and accepts multiple dialogs handles to send on:

   ON CONVERSATION [(]conversation_handle [,.. @conversation_handle_n][)]
   [ MESSAGE TYPE message_type_name ]
   [ ( message_body_expression ) ]
[ ; ]

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Online non-NULL with values column add in SQL Server 2012

July 13th, 2011

Prior to SQL Server 2012 when you add a new non-NULLable column with default values to an existing table a size-of data operation occurs: every row in the table is updated to add the default value of the new column. For small tables this is insignificant, but for large tables this can be so problematic as to completely prohibit the operation. But starting with SQL Server 2012 the operation is, in most cases, instantaneous: only the table metadata is changed, no rows are being updated.

Lets look at a simple example, we’ll create a table with some rows and then add a non-NULL column with default values. First create and populate the table:

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How to update a table with a columnstore index

July 13th, 2011

In my previous article How to use columnstore indexes in SQL Server we’ve seen how to create a columnstore index on a table and how certain queries can significantly reduce the IO needed and thus increase in performance by leveraging this new feature. But once a columnstore index is added to a table the table becomes read-only as it cannot be updated. Trying to insert a new row in the table will result in an error:

insert into sales ([date],itemid, price, quantity) values ('20110713', 1,1.0,1);

Msg 35330, Level 15, State 1, Line 1
INSERT statement failed because data cannot be updated in a table with a columnstore index. Consider disabling the columnstore index before issuing the INSERT statement, then rebuilding the columnstore index after INSERT is complete.

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How to use columnstore indexes in SQL Server

July 13th, 2011

Column oriented storage is the data storage of choice for data warehouse and business analysis applications. Column oriented storage allows for a high data compression rate and as such it can increase processing speed primarily by reducing the IO needs. Now SQL Server allows for creating column oriented indexes (called COLUMNSTORE indexes) and thus brings the benefits of this highly efficient BI oriented indexes in the same engine that runs the OLTP workload. The syntax for creating columnstore indexes is described on MSDN at CREATE COLUMNSTORE INDEX. Lets walk trough a very simple example of how to create and use a columnstore index. First lets have a dummy sales table:

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