sql server varchar max performance issues

In the development of database application project, some binary image data are often used, and the data of storing and reading the display image mainly adopts path link method and memory flow method. The path link method is to save the image file in a fixed path, the database only stores the path and name of the image file, this method has small database capacity, fast access speed, but less security; the memory flow method is to store the binary data directly in the database, this method is con

Tags: advance option ons base own data mem conf everDo SQL Server memory Max memory set the idea, the maximum value of 0, how can not connect to the database, which is really urgent ah, finally saw a text command to save back, other very simple urgency is not come up.1. Pause all SQL

In SQL Server, smaller data can be stored using varchar (n), nvarchar (n), and varbinary (n) types, storing large data, using varchar (max), nvarchar (max), and varbinary (max ) Instead

With regard to the use of SQL Server Profiler, there are already many tutorials on the web, such as this article: SQL Server Profiler: How to use and metrics. Microsoft Official Documentation: https://msdn.microsoft.com/zh-cn/library/ms179428 (v=sql.105). aspx is described i

a varchar high.(4) Why use nvarchar?with n prefixes, n denotes Unicode characters, that is, all characters account for two bytes, Nchar,nvarcharCharacter, the English characters only need one byte storage is sufficient, but the Chinese character is numerous, requires two bytes of storage, English and Chinese characters are prone to confusion, the Unicode character set is to solve the problem of incompatible character sets, all of its characters are r

Tags: fixed har char trim definition length take number requires VarThe length of the char type is immutable in SQL Server, and the length of the varchar is variable.When depositing data:If the data type is char, when a fixed length of a field is defined, if the length of the stored data is less than the length of char, then the length of data stored in the data

Tags: decimal point index VAR technology does not convert SRC int typeSELECT * FROM table nameOrder BY Convert (int,left (column name, CHARINDEX ('. ', column name + '. ') -1) ASC, column name ASCCHARINDEX ('. ', column name) query first. (dot) in the number ofCHARINDEX ('. ', column name + '. ') Give no data to the last side Add. (points) This allows the first digit to be found without a decimal point.Left (column name, CHARINDEX ('. ', column name)) Query decimal valueLeft (column name, CHARIN

value is 0, which means that the maximum number of connections for SQL Server is 32767 by default.Get the maximum number of connections currently set:Select value from Master.dbo.sysconfigures where [config]=103How to monitor the number of SQL Server connections/* Query the number of connections */Select Loginame,coun

Using SQL Server Management StudioTo configure the user connections option1.In Object Explorer, right-click a server and click Properties.2.Click the Connections node.3.Under Connections, in the Max number of concurrent Connections box, type or select a value from 0 through 32767 to set t He maximum number of users tha

following is the optimization of the SQL statement in fact, SQL is not complex, but the data of these tables are slightly larger, but also nested inside more complex business logic, history after several rounds of "master" in the index of the whole side of the optimization, can also run normally but over time, the amount of data in the table is getting larger , boiled frog in warm water,

Yesterday's SQL Server query performance optimization-index creation principle (I) mainly introduced the principle. today are some of the main principles and checks the created indexes. Iii. indexing principles In general, building indexes depends on the data usage scenarios. In other words, which SQL statements are co

Original http://www.cnblogs.com/BoyceYang/archive/2013/06/15/3138142.html Read navigation 1. Overview 2.RulesLogic Database Design 3.EnableDesign with efficient Indexes 4.EnableEfficient Query Design 5.EnableLow performance analysis with technology 6. Summary 1. Overview This is the most effective way to optimize SQL server

This article is an example of SQL Server 2005 solution to the maximum data type problem. Things started very simply. Megaware's marketing department wants a new Web site to publish documents, and the development team feels that using a SQL Server 2000 database as a document storage repository makes things ea

Tags: Microsoft CTI object Complex problem: Lis use parameter BinThis article belongs to theUnderstand the mysteries of performance-slow in applications, fast in SSMS"seriesNext: Understanding the Mysteries of performance-application slow, SSMs fast (5)--case: How to deal with parameter sniffing We put aside the argument sniffing topic and went back to the original point of concern in this series: Why is th

Label:Poptest is the only training institute for developing Test and development engineers in China, aiming at the ability of the trainees to be competent in automated testing, performance testing and testing tools development. In Poptest's LoadRunner training, in order to improve the performance of students experience, add a lot of server optimization knowledge,

these tables in steps.Other circumstances. You should control the use of temporal tables and table variables.Note the collation.About temporal table generation use SELECT into and create TABLE + INSERT into options.6. Avoid using cursorsFor some line-by-row processing, consider putting the clientConsider using an associated subquery instead of a cursorThe following issues must be noted when using cursors:Use an efficient cursor type (such as forward-

improve the performance. DECLARE @Query VARCHAR(100)SET @Query = 'SELECT * FROM Sales.Customers WHERE contactname = @contactname'EXECUTE sp_executesql @Query,N'@contactname VARCHAR(50)',@contactname = 'Allen, Michael' TRY-CATCH for Exception Handling After SQL Server 2005,

SQL Server Full-text indexing performance has been not too good, listen to colleagues today to share, found a skill, go back to try, found that can obviously improve the performance of full-text indexing, generally can improve twice times + Original SQL statement: SELECT

disperse the concurrency pressure of the large scale data, also can speed up the speed of special query, the redundant field can reduce the connection of database table effectively and improve the efficiency.3.Design of the primary keyThe primary key is necessary, and the primary key for SQL Server is a unique index, and in practice, we tend to choose the smallest key group to work as the primary key, so t

Label:The IO performance of SQL Server is affected by the IO latency of the physical disk and the IO operations performed internally by SQL Server. When monitoring disk performance, the primary measure (metric) is IO latency, whic