sql cte performance

Label:Currently in a project optimization, want to analyze SQL Server system performance through the database layer, check the online code, modify the title and DMVs code, the following code can be used to analyze the system after a period of time, those statements are system busy SQL statement. As a reference. Alternative use: Once in the analysis of a reconcili

. SQL Server Execution Time: CPU time = 17188 milliseconds, time consuming = 17261 milliseconds. (1 rows affected) SQL Server Execution Time: CPU time = 0 milliseconds, time consuming = 0 milliseconds. */ Comparing 2000 and 2008 can be found 2008 CPU time is significantly higher than 2000, 2008 worktable logical reads, than 2000 of the higher, This has a worktable scanning technology, 20

'the value of the Key5' fromheadertable awhereA.headerid= 10000 SELECTA.*, t.a0001 as 'the value of the Key1', t.a0002 as 'the value of the Key2', t.a0003 as 'the value of the Key3', t.a0004 as 'the value of the Key4', t.a0005 as 'the value of the Key5' fromHeadertable AInner Join (SelectHeaderid, Detailkey, detailvalues fromdetailtable) T Pivot (MAX(detailvalues) forDetailkeyinch(a0001,a0002,a0003,a0004,a0005)) T onT.headerid=A.headeridwhereA.headerid= 10000 　　

A few days ago, a friend found me and said a SQL performance problem to see if it could be optimized, the following is the process:Snow Leopard 9:35:10Are you thereOrchid Island Main 15:07:39Busy forgetting, what's up?Snow Leopard 15:07:49WellSnow Leopard 15:07:54Database optimization IssuesOrchid Island Main 15:08:04Oh, you said.Snow Leopard 15:09:09Select Distincta.suite_no,b.bd_nm,b.crt_date from (select

During project optimization, I want to analyze SQL server system performance through the database layer. I checked the online code and modified the title and dmvs code, the following code analyzes the SQL statements that are busy after the system runs for a period of time. For reference. Alternative use: When analyzing a reconciliation function, I checked the sy

At present, I want to analyze the SQL server system performance through the database layer during project optimization.Code, Changed the title and dmvs code. The following code can be used to analyze the SQL statements that are busy in the system after the system runs for a period of time. For reference. Alternative use: When analyzing a reconciliation functi

of the underlying data is run multiple times.Reducing the number of data transformations may require data conversion to be a design problem, but the reduction is achievable.Merge multiple update for the same condition on the same table,The update operation does not split into the form of a delete operation +insert operation. Although the function is the same. But the performance difference is very big.Don't write any queries that don't make sense.Whe

Now the development system involves querying by page. when doing this, I am thinking, whether or not the query SQL statement can be automatically encapsulated by parameters into the ability to count the data size of the query statement that is not queried by page. for example, the general practice is: 1. first query based on the concatenated SQL statement: select * fromecs_goodswheregoods_type1limit1000, 10

During database design, sometimes attribute record values belonging to the same person are stored in multiple records for the purpose of data standardization, you want to merge multiple attribute data into one row for display. This is a row-to-column conversion. For example, the score table. What is the efficiency of Row-to-column conversion? I tried the following three methods to perform a row-to-column test. The number of records in the test data table is 120Tens of thousands of fields1

In order to optimize the performance of Microsoft SQL Server most effectively, you must be clear about where performance will be maximized in terms of changing circumstances and focus on these aspects. Otherwise, you may spend a lot of time and effort on these issues, while performance is not significantly improved.Mos

Label:SET STATISTICS profile on: Displays the time, in milliseconds, that is required to parse, compile, and execute the query.SET STATISTICS IO on: Reports information about the number of scans per table referenced in the statement, the number of logical reads (pages accessed in the cache), and the number of physical reads (the number of times the disk was accessed).Set STATISTICS time on: Displays the result set after each query execution, representing the configuration file that the query exe

Chapter 2 procedural performance tuning of PL/SQL applications I. Reasons for PL/SQL Performance problems When the execution efficiency of PL/SQL-based applications is low, it is usually caused by poor SQL statements and prog

of tempdb will have a significant impact on the entire DB. Optimizing the performance of tempdb is important, Especially for large databases. Note: Before optimizing tempdb, consider the impact of tempdb on SQL Server performance, assess the problems encountered, and the feasibility. 　　3.1 Minimized use of tempdb Many of the activities in

Label:Original: SQL Server 2008 Performance Troubleshooting (i)--IntroductionRemark: I spent a lot of work time translation, no plagiarism, allow reprint, but please indicate the source. Because of the length, not a post all finished, but also not so fast all translated, so according to the chapter published. Due to my limited level, translation results must be problematic, in order not to mislead, at the e

weeks data in tens of millions of.Lan Hua Main 16:13:22Ok.Orchid Island Main 16:16:29So change the SQL:with T1 as (Select count (t.c1), t.c1,t.c2,t.c3,t.c4,t.c5From Tab1 twhere T.c2 not in (' Val1 ', ' val2 ', ' val3 ', ' val4 ', ' VAL5 ')and C1 is not NULLGroup by T.C1, T.C2,T.C3,T.C4,T.C5)Select T1.c1,t1.c2,t1.c3,t1.c4,t1.c5from T1Where NOT EXISTS (Select/*+ Use_hash (m,n) */M.C1, M.C2,M.C3,M.C4,M.C5from T1 m,tab2 Nwhere N.c2 > Sysdate-14and m.c1 = N.c1and t1.c2 = M.C2);Orchid Island Main 16:

, without being hindered by interaction. Like what: Use a specific report server as a front-end server to process all report creation requests, so that other servers are free to process interactive reports. Use one or more report servers to handle the production of ordered subscriptions or event-driven reports. General performance Optimization Techniques Because the report server directory is managed by

Label:Using Performance Monitorby BRAD McGehee As you probably already know, SQL Server was very good at tuning itself. It has the ability to monitor itself, and through a feedback loops, it knows how to internally adjust and tune itself so th At it keeps running efficiently, even when external events, such as the number of user connections or the amount of Availa Ble RAM, change over time. But as we all kn

Some factors that affect the performance of SQL Server databases and the principle of optimizing the performance of SQL Server, and some guiding principles are proposed to optimize the performance of the database. Designing an application system does not seem difficult,

? Use SQL Optimization guidance for:– Identify the SQL statements that use the most resources – optimize the SQL statements that use the most resources? Optimize workloads with SQL access guidance SQL optimization SQL