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Show all index and heap access operators in the plan cache

with xmlnamespaces (default 'http://schemas.microsoft.com/sqlserver/2004/07/showplan') select x.value(N'@NodeId',N'int') as NodeId , x.value(N'@PhysicalOp', N'sysname') as PhysicalOp , x.value(N'@LogicalOp', N'sysname') as LogicalOp , ox.value(N'@Database',N'sysname') Read More...
Posted 28 ianuarie 2012 01:42 from rusanu.com | (Comments Off)

Understanding Hash, Sort and Exchange Spill events

Certain SQL Server query execution operations are calibrated to perform best by using a (somewhat) large amount of memory as intermediate storage. The Query Optimizer will choose a plan and estimate the cost based on these operators using this memory Read More...
Posted 19 octombrie 2011 22:28 from rusanu.com | (Comments Off)

Online Index Operations for indexes containing LOB columns

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 Read More...
Posted 6 august 2011 00:26 from rusanu.com | (Comments Off)

Online non-NULL with values column add in SQL Server 11

Prior to SQL Server 11 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, Read More...
Posted 14 iulie 2011 04:56 from rusanu.com | (Comments Off)

How to update a table with a columnstore index

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. Read More...
Posted 13 iulie 2011 11:01 from rusanu.com | (Comments Off)

How to use columnstore indexes in SQL Server

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. Read More...
Posted 13 iulie 2011 10:20 from rusanu.com | (Comments Off)

FILESTREAM MVC: Download and Upload images from SQL Server

In a previous article I have shown how it is possible to use efficient streaming semantics when Download and Upload images from SQL Server via ASP.Net MVC. In this article I will go over an alternative approach that relies on the FILESTREAM column types Read More...
Posted 7 februarie 2011 06:05 from rusanu.com | (Comments Off)

How to pass a NULL value in a message to a queue in SQL Server

The SEND Transact-SQL verb does not allow to send a NULL message body, attempting to do so will result in error: Msg 8433, Level 16, State 1, Line 11 The message body may not be NULL. A zero-length UNICODE or binary string is allowed. But there are ways Read More...
Posted 15 ianuarie 2011 20:08 from rusanu.com | (Comments Off)

This server supports version 662 and earlier…

A new error started showing up in SQL Server 2008 SP2 installations: The database cannot be opened because it is version 661. This server supports version 662 and earlier. A downgrade path is not supported. 661 sure is earlier than 662, so what seems Read More...
Posted 23 noiembrie 2010 19:58 from rusanu.com | (Comments Off)

TRY CATCH THROW: Error handling changes in T-SQL

When SQL Server 2005 introduced BEGIN TRY and BEGIN CATCH syntax, it was a huge improvement over the previous error handling based on @@ERROR check after each statement. Finally, T-SQL joined the rank of programming languages, no more just a data access Read More...
Posted 22 noiembrie 2010 19:42 from rusanu.com | (Comments Off)

SQL Server 2005: Execution Context

This post is based on an old presentation I gave several years back. A video of the presentation used to be available here , but today I couldn't get it to work, so I am attempting to make available most of the information from the presentation within Read More...
Posted 25 august 2010 05:13 from Laurentiu Cristofor's blog @microsoft.com | (Comments Off)

SqlDependency based caching of LINQ Queries

Query Notifications is the SQL Server feature that allows a client to subscribe to notifications that are sent when data in the database changes irrelevant of how that change occurs. I have talked before about how Query Notifications works in the article Read More...
Posted 4 august 2010 23:23 from rusanu.com | (Comments Off)

A New Must Read Blog (if you are interested in Microsoft BI)

Cristian Petculescu is the Principal Architect of SQL Server Analysis Services. He is in part responsible for everything good that came out of SQL Server Analysis Services in the last 13 years or so. Also, responsible for part of PowerPivot. That really, Read More...
Posted 22 iunie 2010 09:48 from DM(X) | (Comments Off)
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The puzzle of U locks in deadlock graphs

In a stackoverflow.com question the user has asked how come a SELECT statement could own a U mode lock? The deadlock indeed suggests that the deadlock victim, a SELECT statement, is owning an U lock on the PK_B index. Why would a SELECT own an U lock? Read More...
Posted 13 mai 2010 00:15 from rusanu.com | (Comments Off)

SQL Server 2008 R2 Express database size limit: 10GB

The SQL Server 2008 R2 Express editions has increased the database size limit to 10Gb from the previous limit of 4Gb. This is great news for many developers, as the 4Gb limitation was by far the most difficult barrier preventing Express adoption. With Read More...
Posted 28 aprilie 2010 20:11 from rusanu.com | (Comments Off)
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