sql server sparse columns performance

the T-SQL statement. But inside SQL Server, it is compiled into an execution plan. The implementation plan is how we obtain the acquisition strategy of the data we need. If you have a performance problem, you need to understand how to read and adjust the resulting execution plan. You will learn the following about the

types of index performance is not the same, should be used as far as possible first high-performanceThe index lookup efficiency of a numeric type is higher than the string type, and the index of fixed-length string char, nchar is higher than the variable-length string varchar, nvarchar.(inefficient) Select ... from tableName where Username= ' Zhang San ' and age>=21(efficient) Select ... from TableName where age>=21 and Username= ' Zhang San 'Second,

high-performance applications. I am not a DBA, but an ordinary developer. The above are some experiences and experiences in my practical work. In view of my very limited level, if you say something wrong or cannot understand it, I hope you can correct it to avoid misleading others. I am very grateful. In the future, I will continue to write some practical experience on SQL

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

SQL Server CPU performance check and optimization related SQL statements, very good SQL statements, recorded here: -- Begin SQL related to CPU Analysis and Optimization -- use DMV to analyze statements that have used the most CPU

Requirements DescriptionIn a production environment, it is often necessary to collect data to locate a problem or to form a baseline.There are many ways to solve the data acquisition in SQL Server, such as trace, Profile, SQLdiag, extended events and so on.Several scenarios have pros and cons, with the beginning of the SQL Server2012 version, Microsoft's start to

, however, it is very likely that a page stores five data records. Because a column has one or two more bytes, only four data records can be stored. You may think that there is nothing to save one piece of data, but after the data volume is very large, there will be significant performance differences between 4 pieces of data and 5 pieces of data on one page. The reason for storing more data on a page is not to save storage costs, but the hard disk is

of addition, subtraction, multiplication, division, the following summary -------------------------------------------- Here is just an extreme example. As a result, a byte deviation is caused to double the occupied storage space. In actual applications, this extreme situation is rare, however, it is very likely that a page stores five data records. Because a column has one or two more bytes, only four data records can be stored. You may think that there is nothing to save one piece of data, but

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 b

occupied storage space. In actual applications, this extreme situation is rare, however, it is very likely that a page stores five data records. Because a column has one or two more bytes, only four data records can be stored. You may think that there is nothing to save one piece of data, but after the data volume is very large, there will be significant performance differences between 4 pieces of data and 5 pieces of data on one page. The reason for

After a period of research, we started to optimize the performance this week. Before optimization, I will summarize some of the information I have investigated. 1. Background This is a system developed in the past 03 years. NET 1.1 + SQL Server 2000, the operating system uses Windows2003. After so many years of use, the operating system was upgraded (from Windows

= 'white'Indexes created on the following columns will be useful to the optimizer.Au_lnameAu_lname, au_fnameThe indexes created in the following columns will not play a good role in the optimizer.Au_addressAu_fname, au_lnameConsider using narrow indexes on one or two columns. Narrow indexes are more effective than multi-index and composite indexes. Use a narrow

statement optimizer that uses is null or is not NULL in the WHERE clause is not allowed to use the index. 3, in and exists exists is far more efficient than in. The inside relates to the full table scan and range scan. Almost all of the in-operation Subcode queries are rewritten as subqueries using exists. 4, in the mass query as little as possible with the format conversion. 5, when in SQL SERVER 2000

example, the following example uses the pubs database. SELECT au_id, au_lname, au_fname from authors WHERE au_lname = ' White ' The indexes established on the following columns will be useful indexes for the optimizer ? au_lname ? au_lname, au_fname The indexes that are built on the following columns will not work well for the optimizer ? au_address ? au_fname, au_lname Consider using narrow indexes on one

performance of the two-range query with YY_BH Index is certainly greatly improved.9. Appropriate and inappropriate in the query conditionsQuery parameters can include actions: =, Inappropriate query parameters are: not,! =, 10. Use Delete sparinglyIn general, some of the logic of deleting data will be implemented more or less in stored procedures. For a small number of tables, the problem is not very big. But for large data tables, deleting data with

Http://www.cnblogs.com/shanyou/archive/2013/02/12/2910232.htmlSQL Server Performance Dashboard reports is a set of Reporting Services reports that are used with reports that are described in SQL Server Management Studio. These reports allow database administrators to quickly determine if bottlenecks exist in their syst

SQL Server Performance Optimization (1) Database Design Can you refer to the recent forum on the emergence of an excellent post http://topic.csdn.net/u/20100415/10/a377d835-acbd-4815-8bcb-b367f88ac8b5.html? 92227Database design includes physical design and logical design:Physical DesignYou can use the raid hardware architecture.To put it simply, the usage policy

personally think that if most of the requests reach the second paradigm, the system will generate fewer columns and more tables, this reduces data redundancy and improves performance. 2, Reasonable redundancy It is almost impossible to design a system completely according to the standardization. Unless the system is very small, it is necessary to add redundancy in a planned manner after the standardization

Brief introduction In SQL Server, data is stored on a page. When you add a clustered index to a table, SQL Server searches for the data by using the columns of the clustered index as the keyword. Therefore, the impact on performance