sql optimization book

SQL Server database optimization solution There are many reasons for slow query speed. The following are common causes: 1. No index or no index is used (this is the most common problem of slow query and is a defect in programming) 2. Low I/O throughput, resulting in a bottleneck effect. 3. the query is not optimized because no computing column is created. 4. Insufficient memory 5. slow network speed 6. The

rcvblls.balance>0ORDER by Cust.nameInto TEMP cust_with_balanceThen query in the temporary table in the following way:SELECT * from Cust_with_balanceWHERE postcode> "98000"The rows in the staging table are less than the rows in the primary table, and the physical order is the required order, reducing disk I/O, so the query effort can be significantly reduced.Note: Changes to the primary table are not reflected when the staging table is created. When data is frequently modified in the primary tab

-correct number of times)/(correct times + errors), 1) as weight from question Left JOIN Answerresult on answerresult. Topic identification = question. Topic identification 　　WHERE User ID ={userid} Description:ifnull ((0-the correct number)/(correct times + error times), 1) This function is divided into 2 parts, Formula: (0-correct number of times)/(correct number + error times) Get the weight of the topic, this interval is [0,-1],0 said only the wrong topic,-1 means to do the right topic.

Original: Set STATISTICS io and set STATISTICS time in SQL Server query performance optimizationIn recent times, has been exploring the SQL Server query performance issues, of course, also aimless search for a lot of information, but also from the online great God's articles learned a lot, here, to the great God salute. It is by the selfless dedication of the great God, so the younger brother also in return

What exactly does Oracle do when it submits an SQL command to Oracle? A good understanding of this problem can help you better analyze the optimization of SQL statements.Executing an SQL statement from start to finish requires 4 steps: Analysis--parsing, semantic analysis, and shared pool checking of submitted

xh_bz = 1 condition is only 0.5%,When the first SQL statement is executed, 99% records are compared with dy_dj and xh_bz. When the second SQL statement is executed, 0.5% records are compared with dy_dj and xh_bz,The CPU usage of the second SQL statement is obviously lower than that of the first SQL statement.B. query

fact each server has only one member table and a distributed partition view. The data location isTransparent.　　 11. Rebuild the index DBCC reindex, DBCC indexdefrag, shrink data and log DBCC shrinkdb, DBCCShrinkfile.Set automatic log shrinking. Do not set Automatic database growth for large databases, which will reduce server performance. T-SQL has a lot of emphasis on writing, the following lists common points: firstFirst, the DBMS processes the que

There are a lot of tutorials on SQL optimization online, but it's messy. Recently there is a time to tidy up a bit, write to share with you, where there are errors and deficiencies, but also please correct the supplement.This article I spent a lot of time looking for information, modification, typesetting, I hope you read, feel good words recommend to more people, let more people see, Correct and supplement

There are a lot of tutorials on SQL optimization online, but it's messy. Recently there is a time to tidy up a bit, write to share with you, where there are errors and deficiencies, but also please correct the supplement.This article I spent a lot of time looking for information, modification, typesetting, I hope you read, feel good words recommend to more people, let more people see, Correct and supplement

Cloud drizzlingThere are a lot of tutorials on SQL optimization online, but it's messy. Recently there is a time to tidy up a bit, write to share with you, where there are errors and deficiencies, but also please correct the supplement.This article I spent a lot of time looking for information, modification, typesetting, I hope you read, feel good words recommend to more people, let more people see, Correct

There are a lot of tutorials on SQL optimization online, but it's messy. Recently there is a time to tidy up a bit, write to share with you, where there are errors and deficiencies, but also please correct the supplement.This article I spent a lot of time looking for information, modification, typesetting, I hope you read, feel good words recommend to more people, let more people see, Correct and supplement

Label:There are a lot of tutorials on SQL optimization online, but it's messy. Recently there is a time to tidy up a bit, write to share with you, where there are errors and deficiencies, but also please correct the supplement. This article I spent a lot of time looking for information, modification, typesetting, I hope you read, feel good words recommend to more people, let more people see, Correct and sup

Label:Performance optimized MySQL optimization Can be optimized from several aspects Hardware system configuration database table structure SQL index Cost from high to the end, the effect from low to high. How do I find the problematic SQL? Use the MySQL slow query log to monitor SQL for efficiency issues. Show variabl

. The data location is transparent to the application.11. Rebuild the index DBCC reindex, DBCC indexdefrag, shrink data and log DBCC shrinkdb, and DBCC shrinkfile. set automatic log shrinking. for large databases, do not set Automatic database growth, which will reduce the server performance. The writing of T-SQL is very important. The following lists common points: first, the process of DBMS processing the query plan is as follows:1. query statement

database design Reasonable and standardized logical database design can produce optimal performance. A large number of narrow tables are a feature of the standard database. A small number of wide tables are non-standard data features. Highly standard databases are usually associated with complex table joint queries, which may damage the database performance. In any case, SQL Server optimization is very e

Tags: adjust ROC title default logical read bring Insert Upd divThere are a lot of tutorials on SQL optimization online, but it's messy. Recently there is a time to tidy up a bit, write to share with you, where there are errors and deficiencies, but also please correct the supplement. This article I spent a lot of time looking for information, modification, typesetting, I hope you read, feel good words reco

Referenced from: http://database.51cto.com/art/201407/445934.htmThere are a lot of tutorials on SQL optimization online, but it's messy. Recently there is a time to tidy up a bit, write to share with you, where there are errors and deficiencies, but also please correct the supplement.This article I spent a lot of time looking for information, modification, typesetting, I hope you read, feel good words recom

I. Purpose of Optimization Application optimization can be divided into two aspects: source code optimization andSQL statement Optimization. Due to changes in program logic, source code optimization is costly in terms of time cost and risk (especially for systems in use ). O

I. Operator Optimization 1. In Operator SQL statements written in are easy to write and understand, which is suitable for modern software development. However, SQL statements using in always have low performance. The following differences exist between SQL statements using in and