sql performance tuning steps

Tags: implementation mechanism originally page organizes tables based on free article content index ClustFollowing the book on SQL tuning (SQL tuning or SQL optimization) in the essentials of high-performance

Tags: and fast speaking tuning market buffer way a completely"High-performance SQL Tuning essentials and Case Resolution" a book has been launched, many enthusiastic readers on the contents of the book and some of the specific questions raised questions, because of the numerous readers plus my daily work busy, here on

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

:16TAB1 small, TAB2 billion level above, two 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 =

. Graduater_business.gradbusinessid = dbo. Graduater_graduaterregist.graduaterguid INNER JOIN dbo. Person_contact ON dbo. Person_basicinfo.personid = dbo. Person_contact.personid INNER JOIN dbo. Person_skill ON dbo. Person_basicinfo.personid = dbo. Person_skill.personid INNER JOIN dbo. Person_employpurpose ON dbo. Person_basicinfo.personid = dbo. Person_employpurpose.personid OPTION (FORCE order) ( With the above steps, we c

:37YesOrchid Island Main 15:34:51Oh.Orchid Island Main 15:35:12Other, not quite understand your data in the situation, not very good fine optimization.Orchid Island Main 15:35:44Should still be quick.Snow Leopard 15:36:34GoodSnow Leopard 15:36:36Let me seeOrchid Island Main 15:37:16For example: The index of the other two tablesSnow Leopard 15:37:31WellOrchid Island Main 15:37:43The full table scan, although the table is small, but to 0.5s, should also be a small proportion.Snow Leopard 15:37:55I

thickness of the arrow lines indicates the amount of data. In a graphical execution plan, each of the different operators has its own property values, and we can move the mouse over the operator icon to view Of course, you can also right-click on the icon, view the properties, go to the Properties panel and view more detailed property values The detailed indicator values for each operator in this case are described later, but there are a few key values here, which can be said to mention a lit

I. Preface Index plays an important role in database performance. The advantages and disadvantages of index design directly affect the efficiency of DB execution. Therefore, when performing DB tuning, some of them will start to process the index. SQL server also provides a good tool for Database Engine Tuning Advisor a

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:

can avoid Key lookup is perfect, let's revise non-clustered index to include it in the index with the Include keyword His fields are:[SQL] DROP INDEX idx_non_clust_salesorddetaildemo_modifieddate on salesorddetaildemo GO CREATE nonclustered INDEX idx_non_clust_salesorddetaildemo_modifieddate on salesorddetaildemo (ModifiedDate) INCLUDE ( ProductID, UnitPrice ) GO --Clear the cache, only for the development environment! DB

statements. Using adbc in the abap environment is similar to using JDBC in the Java environment. The reports and transactions they write can use any available interface to access the database. Use DB2 parameters in SAP Open SQL SAP supports a batch of DB2 parameters that can be added to Open SQL statements to affect how natural SQL statements generated from Open

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

. When a query is executed, SQL Server does not read more or less data than is actually required, so when executing the same query on the same dataset, the resulting logical read numbers are always the same.Why is it important to know the logical read value of SQL Server when executing queries in tuning query performance