sql tuning tutorial

Label:Original: SQL Server Tuning Series BasicsObjectiveAbout SQL Server Tuning series is a huge content system, not a word two words can be analyzed clearly, this article first in the SQL tuning in the most commonly used query pl

Label:I believe a lot of friends, whether it is to do development, architecture, or DBA, are often heard of the word "tuning". Talk about "tuning", may make a lot of technical staff heart passion, also may make a lot of people feel distressed, do not know how to start. Of course, there are many people who are dismissive of this, because not everyone does the project is very high performance requirements. In

ObjectiveAbout SQL Server Tuning series is a huge content system, not a word two words can be analyzed clearly, this article first in the SQL tuning in the most commonly used query plan to parse, to do a good job of the basic grasp, tamping basic skills! Then we talk about the overall statement tuning.Learn how to read

ObjectiveAbout SQL Server Tuning series is a huge content system, not a word two words can be analyzed clearly, this article first in the SQL tuning in the most commonly used query plan to parse, to do a good job of the basic grasp, tamping basic skills! Then we talk about the overall statement tuning.Learn how to read

How to use STA (SQL tuning advisor), tuningadvisor1. manually generate SQL tuning advisor1. SQL text format:DECLAREMy_task_name VARCHAR2 (30 );My_sqltext CLOB;BEGINMy_sqltext: = 'select * FROM DBA_SEGMENTS where owner = ''clic' AND SEGMENT_TYPE = ''table ''';My_task_name: =

Use Cases I remember when I was tuning for a company, the person in charge sent me a bunch of business T-SQL scripts, I am still calm in the face of massive scripts, although I do not understand the internal complex business, however, we have to focus on the key "slowness" of the problem. We will filter them out based on the "slowness" of the query and optimize them one by one. Won't the problem be solved q

gp4.1 and previous SQL with not in will be executed with Cartesian product, using nested join, very poor efficiency Not in== use the left join to go back to the table Association to implement Example select * from test1 where col1 not in (select col2 from test1)Switch select * from test1 a left join (select col2 from test1 group bycol2) b on a.col1=b.col2 where b.col2 is nullThe run time is increased from more than 30 seconds

. server.2005. Technical Insider "series Conclusion This article first to this bar, short, easy to understand, this article mainly introduces the query plan of the joint operators, the next we analyze SQL Server parallel operations, in multicore hyper-threading gathered today, see SQL How server uses parallel operations to maximize the use of existing hardware resources to improve performance, is inte

would recommend adjusting your index design to create an overlay index to ensure the stability of the plan. But forcing a specific execution plan is just a temporary fix-you still have to fix the root cause of your problem. Summary Don't get me wrong: query storage in SQL Server 2016 is a great feature that will help you understand planned regression more easily. It will also help you "temporarily" enforce a specific execution plan. But the goal of p

[Oracle] oracledba6 SQL Tuning sets, oracledba6tuning You want to use the SQL Tuning Advisor to generate recommendation S for badly written SQL statements in your development environment. W Hich three sources can you select for the advisor to analyze? (Choose Three .) A

Tags: Database tuning database performance optimizing MySQL performanceVi. other optimization methods of MySQL Database In the last chapter, we talk about some optimization methods that are not covered before. 1. My.ini configuration file Here are only two of the most important, but the others are more. 1) Configure the maximum number of connections The default is 100, and the recommended setting is 1000 2) Configure the cache On the My.ini [mysqld]

Tag: Time Condition number column arch OSI user CTE codeIn section 1.5 of the SQL Tuning Basics Overview 05-oracle Index Type and introduction, several "Common index execution plans" are mentioned: Index full Scan: Fully scanned indexes, block read, orderedIndex range Scan: Range sweep of indexIndex fast full Scan: Fast all scans of indexes, multiple reads, unorderedINDEX full SCAN (Min/max): Query

Performance Tuning for mysql SQL statements Performance Tuning for mysql SQL statements In server development, there are sometimes requirements on the concurrency, and sometimes an SQL statement, such as a stored procedure, affects the speed. Now, if the execution of an

same time, tracking different databases and tablesIf you are working with Database Engine Tuning Advisor for SQL, it's better to analyze your SQL statement performance if, and will tell you how to modify it would be better, let's have a look.How Database Engine Tuning Advisor is used With this tracking record, h

Label:You want to use the SQL Tuning Advisor to generate recommendations for badly written SQL statements in your development environment. WHich Three sources can you select for the advisor to analyze? (ChooseThree.)A. Top SQLB. SnapshotsC. SQL Tuning SetsD. Index Access Pat

Label:You want to use the SQL Tuning Advisor to generate recommendations for badly written SQL statements in your development environment. WHich Three sources can you select for the advisor to analyze? (ChooseThree.)A. Top SQLB. SnapshotsC. SQL Tuning SetsD. Index Access Pat

. Orderid,o1. Freightfrom Orders o1where O1. Freight>( SELECT AVG (O2). Freight) from Orders O2)The goal of SQL execution is to query orders that have more than the average shipping charge in the order.The clause that extracts the average freight here is a completely independent subquery that executes independently of the main query. At the same time here we take advantage of a scalar computation (AVG) so that it returns exactly one row.Look at th

SQL Server Performance Tuning 3 (Index) MaintenanceHeat1 reviews Brook Stream GrassSQL Server Performance Tuning 3 (Index) MaintenanceObjectiveThe previous article describes how to improve the query performance of a database by building an index, which is really just the beginning. Subsequent to the lack of proper maintenance, the index you created earlier can e

Speaking of the tuning of SQL Server, I think everyone would like to know this knowledge. I am also exploring the way, we have any good ideas, welcome to discuss and study. Win the people's long, can avoid weaknesses. This article is mainly from the programmer's SQL code, if you want to read, you can download the Internet to read (of course, the best way to buy

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