index performance tuning in sql server

Temporary tables vs. Table variables and their impact on SQL Server Performance -- Wang Chenghui translation finishing, post please indicate from Microsoft Bi pioneer http://www.windbi.com/--Original post addressIn the temporary tableCreate Table # T (...)And table VariablesDeclare @ t table (...)There are three major differences in theory.FirstTransaction l

= ' B B ' where id=2 select col2 from Ta where id=2--rollback tran--------------------------------Connection window 2 SET T Ransaction Isolation LEVEL Read COMMITTED--set Session Read Committed: Specifies that the statement cannot read data that has been modified by another transaction but has not yet been submitted begin TRAN select * FROM TA How to:--------------------------------Connect Windows 2 (use session settings: Business data is constantly changing, as is available when sales

implemented in a stored procedure, we use a undocument query hint directly on the statement, which causes the parallel cost threshold of the query to be reduced to 0, which forces the statement to go parallel and the statement execution time from 20 seconds to 5 seconds (note: Using the hash join hint is 7 seconds). The following is a simple example of the effect of using this hint, as shown in Listing 1 of the sample T-sql: from [AdventureWorks]. [S

Microsoft, one is not perfect function also dare to take Out (2000) The second functional architecture of the outstanding design makes the function has a strong continuity and Scalability (2005 2000 of the function to retain and improve). The optimization tool is simple to use 1: Use SQL Server Porfiler (Event Viewer) to record all the steps of the operation database in the business system and save it as

Measure_heat Show Results: The results are rather ugly and clear, we can use the graphical visualization of the way to view, the display is more intuitive. 4. There are also set functions related to performance analysis, such as SET STATISTICS XML --XML format output query plan SETSTATISTICS profile on -- Each query that executes returns its regular result set For example, when profile is set to ON, the result is much like set SHOWPLAN_ALL on, w

Before you start, take a look at Microsoft's recommendations: In the overall performance optimization of the system, the TSQL optimization priority is not the highest. This article consists of four parts: SET STATISTICS time on SET STATISTICS IO SET Showplan_all on SET STATISTICS profile on The SET function is primarily intended to show the SQL execution query plan, CPU, and

Background:New servers that require increased performance monitoring to find that performance metrics cannot be read through PowerShellWorkaround: Open the Registry Editor by going to the Start Menu and selecting Run ..., then type "regedit", and click the OK button. Navigate to the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurePipeServers\winreg registry key. Right click on t

'@ PkName nvarchar (50) = 'id', -- primary key name@ StrOrder varchar (255) = '', -- Name of the sorted field, for example, 'order by id desc'@ StrWhere varchar (1500) = '', -- Query condition (Note: Do not add where), for example, 'xname like ''' % 222 name % '''@ PageIndex int = 1, -- page number, for example, 2@ PageSize int = 20, -- number of records per page, for example, 20@ RecordCount int = 0 out, -- total number of records@ DoCount bit = 0 -- if the value is not 0, statistics are collec

to the table will cause the view to not be automatically added, although we can refresh the view by Sp_refreshview or sp_refreshmodule, but to avoid confusion, It is best to explicitly list the name of the required column in the view definition, and if additional columns are added and we need additional columns in the view, we can modify the view definition by Alter VIEW.View query returns extra columns resulting in inefficient query performance thro

Win R2 Install SQL Server 2008 "performance counter registry hive consistency" failure resolution (2011-02-23 19:37:32)reproduced When you install database 2008 on an HP server today, there is always a point in the database installation detection that indicates that the

Use this statement frequently to view poorly-performing SQL statements:SELECTCreation_time N'Statement Compilation Time', Last_execution_time N'Last Execution Time', Total_physical_reads N'total number of physical reads', Total_logical_reads/Execution_count N'each logical read Count', Total_logical_reads N'total number of logical reads', Total_logical_writes N'total number of logical writes', Execution_count N'Number of executions', Total_worker_time/

Brief introductionSQL Server Query Analyzer is cost-based. Typically, the Query Analyzer determines how to choose an efficient query route based on predicates, such as which index to choose. And every time the Query Analyzer looking for the path, and not every time to statistics the number of rows included in the index, the range of values, but based on certain conditions to create and update the information after the save to the database, which is ca

I. Concept and classification of indexesThe concept of indexing everyone knows that we also use common clustered indexes, nonclustered indexes in our daily development. However, in addition to these two, SQL Server also provides other indexes, such as:A. Unique index: An index that does not contain duplicate keys, and either a clustered index or a nonclustered index can be a unique index.B. Index containing

From: http://www.cnblogs.com/chillsrc/archive/2008/04/15/1154186.html I. Environment and test requirements 1. Test Environment ① Hardware: CPU: 2 GB, memory: 2 GB ② Database: SQL 2005 The result varies depending on the machine configuration. 2. Performance Test Description ① Query after the database server is restarted, that is, the result of the fi

Most SQL Server tables require indexes to speed up data access. If no indexes are available, SQL Server performs a table scan to read each record in the table to locate the requested data. Indexes can be divided into cluster indexes and non-cluster indexes. Cluster indexes increase the data access speed by rearranging

reads and writes per second exceeds 58, the I/O bottleneck occurs. 2. Memory Counter: Paging file: % usage Note: displays the number of page file examples in use in percentages. See Process \ page file bytes. Bottleneck: over 70% 3. CPU Counter: SQL server: SQL statistics: Batch requests/sec Description: Number of SQL

There are already many paging query methods, and I am also a member here. SQL Server has a set rowcount setting, which means that the command processing stops processing the command after responding to the specified number of rows, we can use it to implement high-performance paging query in a 10 million row-level data table. Let's talk about the implementation me

Paging query has a lot of ways, and here I also join as a member. SQL Server has a SET ROWCOUNT setting that means that the processing of a command stops processing the command after responding to a specified number of rows, and this feature allows us to use it to implement a high-performance paging query in a tens of millions of row-level datasheets. First of al

(@pagesize) * FROM (select Top (@page * @pagesize) * createtime desc) liwu_items ORDER BY createtime ASC) b ORDER BY createtime Desc Results (12 rows affected) Table ' Liwu_items '. Scan count 1, logical read 7 times, physical read 0 times, read 317 times, LOB logic read 0 times, lob physical read 0 times, lob read 0 times. Execution plan The execution plan is similar to the first, but two of the resources are quite a bit. The third, one of the most rubbish, is implemented

There should be different filegroups in the database before the partition table is created;Assuming the database name is Df17datapro, create the user table UserID, put the first 500,000 data in the primary filegroup, place the 50~100 in the FG1 filegroup, and put more than 100 in the FG2 filegroup1. Add File group Fg1,fg2ALTER DATABASE Df17datapro ADD FILEGROUP FG1ALTER DATABASE df17dataproadd FILEGROUP fg22. Adding files to a filegroupALTER TABLEDf17dataproADD FILE(NAME=Df17datapro1,filename=