sql cte performance

Tags: Performance image view function mit return virt src Createdynamic management Views: Specific instance statements: --on the basic situation of statement executionSELECT * FROM Sys.dm_exec_query_stats--dynamic management functions need to provide parametersSelect Top Ten Execution_count,total_worker_time,t.text,total_worker_time/execution_countAs Avgcpu from Sys.dm_exec_query_stats as SCross apply Sys.dm_exec_sql_text (S.sql_handle) as TORDER BY

Windows Server 2008 R2 en enterprise 64bitSQL Server 2008 R2 en enterprise 64bit Symptom: the performance counters related to SQL Server are not displayed in Performance Monitor. Solution: Rebuilding the counters:CD c: \ windows \ system32Lodctr/RCd c: \ WINDOWS \ syswow64Lodctr/R Resyncing the counters with Windows Management Instrumentation (Wmi ):Winmgmt.

performance of tempdb, especially for large databases. Note: before optimizing tempdb, consider the impact of tempdb on SQL Server performance, and evaluate the problems and feasibility. 3.1 minimize the use of tempdb Many activities of SQL Server occur in tempdb. In some cases, you can reduce excessive use of tempdb

Tags: Microsoft CTI object Complex problem: Lis use parameter BinThis article belongs to theUnderstand the mysteries of performance-slow in applications, fast in SSMS"seriesNext: Understanding the Mysteries of performance-application slow, SSMs fast (5)--case: How to deal with parameter sniffing We put aside the argument sniffing topic and went back to the original point of concern in this series: Why is th

Tags: Data Warehouse res warehouse IMA Misc SYS cell nbsp HighlightTo configure the Data collector: 1. Create a login and map roles 2. Configuring the Management Data Warehouse 3. Create collection sets, collection items----msdb data store sp_syscollector_create ... 4. Automatically configure the related job Specific steps: After creating the diagram: To configure Data collection: The refresh looks like this: The method created: Use msdb go declare @collectionsetid int --return val

. 3.1 minimize the use of tempdb Many activities of SQL Server occur in tempdb. In some cases, you can reduce excessive use of tempdb to improve the overall performance of SQL Server. There are several places where tempdb is used: (1) temporary tables created by the user. If you do not need them, try to avoid them. If you use temporary tables to store large a

In practical applications, there are 3 ways to analyze a single query SQL performance: Show status, show profiles, and slow query logs. First, use show profile 1, the default is disabled, open in the session #开启profileSet profiling=1; 2. When a query arrives at the server, the tool logs the profiling information to a temporary table and gives the query an integer identifier starting at 1, which can be v

can ensure that the database will faint. In addition, execution plans can be reused, and the simpler SQL statements are more likely to be reused. Complex SQL statements have to be re-parsed as long as one character changes, and then the bulk of the garbage is stuck in memory. It is conceivable how inefficient the database will be. 4. Staging intermediate results using temporary table An important way to si

that the database will faint.In addition, execution plans can be reused, and the simpler SQL statements are more likely to be reused. Complex SQL statements have to be re-parsed as long as one character changes, and then the bulk of the garbage is stuck in memory. It is conceivable how inefficient the database will be.4. Staging intermediate results using temporary tableAn important way to simplify

Optimizing SQL queries: How to write high-performance SQL statements1, first to understand what is called the implementation plan?An execution plan is a query scheme that the database makes based on the statistics of SQL statements and related tables, which are generated automatically by the query optimizer, such as an

Recent project team colleagues told me that there was a SQL performance problem, he said the entire table has only 69 records, client execution cost two minutes, very unscientific. I helped analyze the cause and get it resolved. The following small series installs similar table structure, constructs a case, the test screenshot looks like this: This table has 13800KB (that is, 13M), because the table save

framework, but not for testing the correctness of the unit code, but for testing the function, whether the performance of the method meets the requirements. such as Ntime. It can concurrently run the same method multiple times to see if the expected performance targets can be achieved. For example, the following code uses the Ntime framework to start 2 threads and execute the MyTest method multiple times i

optimization phase. If the difference between the two is very large, the actual performance statistics are stored as statistical information feedback, and the statement is also marked as re-optimized. When the statement is executed the next time, statistical feedback is used to select a more appropriate degree of parallelism (DOP).--Note:1) from the Oracle 11GR2 backwards, the parallel hint in the statement will cause the system to automatically sele

Tags: style blog http color using SP strong on dataRecently a friend and I explored whether statements about where 1=1 and this form would affect performance. The final conclusion is not affected. Although the conclusion is correct, the understanding of the problem is far from the root of solving the problem. In fact, in the writing process of T-SQL statements often make a very narrow conclusion, and then d

SQL Server Performance Tuning methodology and common tools, SQL Server Tuning In earlier articles, we mentioned the DETECT methodology in Performance Tuning. Here we will briefly review the DETECT methodology. Discover the problem: found the problem Lead e the conditions: Explore causes Track down possible approaches:

After a piece of SQL code is written, you can initially predict the performance of the SQL at run time by looking at the SQL execution plan, especially if you find that the SQL statement is inefficient, we can analyze the problem of the