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Bug #: 50001268 (SQL Hotfix)
Microsoft distributes Microsoft SQL Server 2005 fixes as one downloadable file. Because the fixes are cumulative, each new release contains all the hotfixes and all the security fixes that were included with the previous SQL Server 2005 fix release.
You install the x64 version of Microsoft SQL Server 2005 Service Pack 2 on a computer that has more than 4 gigabytes (GB) of memory. When you run a query and the query optimizer uses a hash join, an access violation may occur. If you use SQL Server Profile to trace the query, you notice an event. In this event, the EventClass column contains an entry that reads Hash Warning. Additionally, the EventSubClass column contains an entry that reads Hash Recursion. When you click the event, the following description appears underneath the event list in the SQL Server Profile window:
Hash Warning Indicates that a hashing operation (for example, hash join, hash aggregate, hash union, and hash distinct) that is not processing on a buffer partition has reverted to an alternate plan. This can occur because of recursion depth, data skew, trace flags, or bit counting.
Additionally, a minidump file is generated in the SQL Server log folder.
The fix for this issue was first released in Cumulative Update 2. For more information about how to obtain this cumulative update package for SQL Server 2005 Service Pack 2, click the following article number to view the article in the Microsoft Knowledge Base:
936305 Cumulative update package 2 for SQL Server 2005 Service Pack 2
Note Because the builds are cumulative, each new fix release contains all the hotfixes and all the security fixes that were included with the previous SQL Server 2005 fix release. Microsoft recommends that you consider applying the most recent fix release that contains this hotfix. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
937137 The SQL Server 2005 builds that were released after SQL Server 2005 Service Pack 2 was released
Microsoft SQL Server 2005 hotfixes are created for specific SQL Server service packs. You must apply a SQL Server 2005 Service Pack 2 hotfix to an installation of SQL Server 2005 Service Pack 2. By default, any hotfix that is provided in a SQL Server service pack is included in the next SQL Server service pack.
To work around this problem, use a join hint to prevent the query optimizer from using a hash join. For example, use a loop join hint or a merge join hint.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about what files are changed, and for information about any prerequisites to apply the cumulative update package that contains the hotfix that is described in this Microsoft Knowledge Base article, click the following article number to view the article in the Microsoft Knowledge Base:
936305 Cumulative update package 2 for SQL Server 2005 Service Pack 2 is available
For more information about the Hash Warning event class, visit the following Microsoft Developer Network (MDSN) Web site: