Hints are options or strategies specified for enforcement by the SQL Server query processor on SELECT, INSERT, UPDATE, or DELETE statements.
Because the SQL Server Query Optimizer typically selects the best execution plan for a query, we recommend only using hints as a last resort for experienced developers and database administrators. Applies to: DELETE INSERT SELECT UPDATE MERGE ...
Because the SQL Server Query Optimizer typically selects the best execution plan for a query, we recommend only using hints as a last resort for experienced developers and database administrators. Applies to: DELETE INSERT SELECT UPDATE MERGE ...
Table 8.2 Optimizer Hints Available Global: The hint applies to the whole query. Query Block: The hint applies to a group of joins. For example, the top level of the query is a query block; a subquery is another query block. Hints that apply to a query block can in some cases also ...
http://msdn.microsoft.com/zh-cn/library/ms187713.aspx 也有资料表示还有所谓的视图提示 http://msdn.microsoft.com/zh-cn/library/ms190237.aspx SQL Server Optimizer Hints By :Brad McGehee http://www.sql-server-performance.com/tips/hints_general_p1.aspx...
select /*+ cardinality(b 100000) */ a.object_name,a.object_type from a,b where a.object_id=b.object_id and b.object_id=1000; 具体来这看 https://docs.oracle.com/cd/B28359_01/server.111/b28274/hintsref.htm#PFGRF501
AlterServerAuditSpecificationStatement AlterServerAuditStatement AlterServerConfigurationBufferPoolExtensionContainerOption AlterServerConfigurationBufferPoolExtensionOption AlterServerConfigurationBufferPoolExtensionOptionKind AlterServerConfigurationBufferPoolExtensionSizeOption AlterServerConfigurationDiagnosticsLogMaxSizeOption ...
Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance SQL database in Microsoft Fabric Table hints are used to override the default behavior of the query optimizer during the data manipulation language (DML) statement. You can specify a locking method, one or more indexes, a qu...
Because the SQL Server query optimizer typically selects the best execution plan for a query, we recommend that hints be used only as a last resort by experienced developers and database administrators. Applies to: DELETE INSERT SELECT UPDATE ...
(c)在单机SQL Server中完成单机优化,形成Final (Serial) Memo,传递给PDW optimizer,枚举Shuffle/Replicate等算子,生成Augmented (Parallel) Memo。 (d)从c的Parallel Memo中选出最优分布式计划 (e)转换为DSQL的plan描述,其中包括DMS operation + SQL operation... 总结 SQL Server PDW的并行优化方案还是非常优雅的...