sql tuning advisor

milliseconds) above and the maximum wait time as a reference. Using the information provided by Sys.sysprocesses to count, about sys.sysprocesses use can refer to "SQL Server performance tuning from user session state analysis". This view listens for blocking information over a period of time. You can set a monitor statement to run every 10 seconds, storing blocking and blocking.Thoughts are as follows:--F

which some statements in SQL Server take advantage of the index may not be clear, our next analysis of this piece, to understand the indexing method and optimization techniques, interested in advance attention, about SQL Server performance tuning involves a wide range of content, followed by an analysis in the next article.If you have any questions, you can leav

to go. In the development, we have to do some optimization of business logic, to avoid complex logic operations, especially to avoid a very large number of cycles of business logic processing, on the one hand we want to simplify business logic, some business logic to the program to deal with, on the other hand we can use SQL very clever to achieve a lot of logic complex requirements, Avoid having to do a lot of complex logic processing, rather than

Tags: database tuning database MySQL SQL performanceV. Optimizing SQL statements The previous chapter tells you how to design a good table, and a good table naturally requires a good SQL statement to manipulate it. This chapter will talk about how to optimize SQL statements.

SQL execution is slow, how fast and accurate optimization. SQLHC is one of the best tools. By getting all the SQL execution plans, list the actual performance bottlenecks, listing the number of rows on the table where SQL resides, the data and distribution of each column, the existing index, the actual execution of

. Reference documents Microsoft Books Online logical operators and physical operator references Refer to the book SQL. server.2005. Technical Insider "series Conclusion This article is here first, this article mainly describes the T-SQL statement tuning from the execution plan, and introduces three common connection operators and aggregation

, eliminate sequential access to large table row data, index connected columns, and use unions to avoid sequential access. Although there are indexes on all the check columns, some forms of where clauses force the optimizer to use sequential access. The following query forces a sequential operation on the Orders table: Select *from orders where (customer_num=104 and order_num>1001) or order_num=1008 although the customer Indexes are built on _num and Order_num, but in the above statement the opt

The following articles mainly describe the ultimate SQL Performance tuning Technology of DB2, including the impact of pointers on the Performance of DB2 databases, DB2 performance tuning technology and a detailed description of more future tuning technologies, the following is the main content of the article. DB2,

-align:middle; "/>There is a question worth thinking about: developing or testing why not in the front of the application of the PID before and after the implementation of the white space function trim, rather than put on the database side to execute, which not only aggravate the workload of the database server,It is also easy to cause the full table scan of large tables due to improper use of the function to reduce the execution speed of SQL; althoug

ObjectiveIn the previous few we analyzed a series of SQL Server-related performance tuning, which I divided into two modules.The first module focuses on the basic content of the master, a total of 6 articles to complete, covering a series of basic algorithms, the detailed analysis of how to view the execution plan, master Execution Plan optimization points, and a list of the everyday we usually write T-

Trust a lot of friends, whether it is to do development, architecture, or DBA, are often heard that the word "tune". Speaking of "tune", may let a lot of technical staff heart surging, may also make a lot of people feel distressed. Of course, there are a lot of people are dismissive of this, because not everyone has access to the project is very large, and not everyone does the project is very high performance requirements. In the mainstream enterprise-level development and Internet application

traces created by SQL scripts or SQL Server Profiler that are stored in a file or table. If you do not have an existing workload record for the database or table that you want to index, you can create one through SQL Server Profiler (see the use of SQL Server Profiler in chapter 19th for a specific method). You can us

indexes are fully utilized during execution. normally, if the index is fully utilized, the name of the execution step will be index seek. note: When analyzing Io, You need to execute the set statistics Io on statement to open the IO analysis.4. Based on the analysis results, add the corresponding indexes and reduce the I/O later.5. for stored procedures, the event viewer should be used to further filter their information. If spid is used (which can be obtained through select @ spid), then the m

|+----------+1 row in Set (0.16 sec)Now you can index it, explain the real SQL statement on the line.Mysql>explainselectpost_idfromtest.tbl_testwherepost_type Add indexMysql> ALTER TABLE Test.tbl_test Add index Idx_f (check_status,flag,post_type,post_time); Query OK, 0 rows affected (4.45 sec) records:0 duplicates:0 warnings:0One more explain, scan 500,000 lines to 2 lines.Mysql>explainselectpost_idfromtest.tbl_testwherepost_type After you have debug

to archive, partition, table sharding, etc) Software System (operating system optimization, database system configuration, resource planning and monitoring, etc) Hardware infrastructure (Device specifications, hardware performance, Server Load balancer, Disaster Tolerance, etc) SQL statement writing, indexing and statistics, transactions and locks, application access code (too many connections, frequent switches, etc) Performance

parallel, said the update statistics to try first.a hit! a hit! a hit! Execute the following code:Update STATISTICS ods_table_a by default, the query optimizer updates the statistics as needed to improve the query plan, but in some cases, you can improve query performance by using update STATISTICS or stored procedure sp_updatestats to update statistics more frequently than the default updates. new inserted data no statistics, large table Automatic UPDATE STATISTICS trigger Automatic Update me

actual situation, using Left/right/inner join, according to explain optimization; b. When there is an order by A.col condition, all joins must be left joins, and Each join field creates an index, and the Where condition can only have a table condition, the data associated with the other table is formed into a large table in a, then the complete set of a is filtered; If you cannot use the left join entirely, you need to use it flexiblyStraight_join and other techniques, take the time sequence as

is much higher than that of the composite Index query efficiency, while in 11.2.0.3 version Verify that the ad hoc query efficiency of the common composite index is more efficient than the efficiency of the bitmap index) Create TableT (name_id, gender not NULL, location not NULL, Age_range not NULL, data) as Selectrownum, Decode ( Floor(Dbms_random.value (0,2)),0,'M',1,'F') gender, Ceil (Dbms_random.value (0, -) Location , decode ( Floor(Dbms_random.value (0,4)),0,' Child',1,' Young',2,'Middle

at this point.Finally, it is important to note that the search scope is too wide to preventIf the DBMS optimizer considers the retrieval scope to be too wide, it discards the index lookup and uses a full table scan. Some of the following may result in a wide range of searchCaseA, using is not null or not equal to judgment, may cause the optimizer to assume that the number of records matched is too many.b, when using the LIKE operator, "a%" will use the index, while "a%c" and "%a" will use a ful

Do you want to learn some tips for tuning SQL PL? If this is the case, this article will describe some common examples of tuning ibm®db2®universal database™ (UDB) V8.2 for linux,unix®, and Windows®, and will pay special attention to porting from other database management systems Come over the process. Motivation SQL p