The following tables describes the query types for which indexes are useful. Note The examples in the table are based on the AdventureWorks2008R2 sample database. When you run the examples in SQL Server Management Studio, you can view the indexes that are selected by the query optimizer by ...
From looking at the indexes and statistics and filtering conditions, our instinct tells us that SQL Server should have used index seek. But supprisingly, SQL Server uses index scan. The table has significant number of rows. This has caused high CPU consumption....
If the query was executed with multiple plans and the last plan is significantly worse than previous plan, you can use the plan forcing mechanism to ensure SQL Server will use the optimal plan for future executions Check if the optimizer is suggesting any missing indexes in XML plan. If yes...
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Create and modify tables and indexes in a database. Query objects by using the SELECT statement. Insert and delete rows in a table. Modify existing data in a table. Compact and repair a database. Expand table To navigate the graphical interface and execute commands in SQL Server Compact 3.5...
optimization phase of query processing—this takes into account many different factors, such as the search predicates used in the query, the tables involved and their join conditions, the list of columns returned, and the presence of useful indexes that can serve as efficient access paths to the...
Reading Query Plans: Stairway to SQL Server Indexes Level 9 ByDavid Durant, 2011/10/05 原文链接:http://www.sqlservercentral.com/articles/Stairway+Series/72441/ The Series 本文是阶梯系列的一部分:SQL Server索引的阶梯。 索引是数据库设计的基础,并告诉开发人员使用数据库大量关于设计者的意图。不幸的是...
The following examples use theINDEXhint. The first example specifies a single index. The second example specifies multiple indexes for a single table reference. In both examples, because you apply theINDEXhint on a table that uses an alias, theTABLE HINTclause must also specify the ...
When you specify exposed_object_name without also specifying a table hint, any indexes you specify in the query as part of a table hint for the object are disregarded. The Query Optimizer then determines index usage. You can use this technique to eliminate the effect of an INDEX ...
The following examples use theINDEXhint. The first example specifies a single index. The second example specifies multiple indexes for a single table reference. In both examples, because you apply theINDEXhint on a table that uses an alias, theTABLE HINTclause must also specify the same alias ...