index performance tuning in sql server

To maximize the performance of SQL Server, you must first identify several aspects. When these several aspects are optimized, the whole system performance can be improved to the greatest extent. You can then analyze these several aspects. Otherwise, you may not be able to do it. Experience has shown that the

'. Scan count 1, logical read 1 times, physical read 0 times, read 0 times, LOB logic read 0 times, lob physical read 0 times, lob read 0 times. (6 rows affected) (1 rows affected) SQL Server Execution Time: CPU time = 0 milliseconds, elapsed time = 528 milliseconds. (500 rows affected) Table ' worktable '. Scan count 0, logical read 0 times, physical read 0 times, read 0 times, LOB logic read 0 times, lob

to archive, partition, table sharding, etc) Software System (operating system optimization, database system configuration, resource planning and monitoring, etc) Hardware infrastructure (Device specifications, hardware performance, Server Load balancer, Disaster Tolerance, etc) SQL statement writing, indexing and statistics, transactions and locks, application a

A few SQL Server paging stored procedure writing and performance comparisonsStored procedure 5 Kinds of pagination, the following code is from the forgotten when from someone else that CTRL + C, so just as a collection, hope the author see don't Spray me.------Create a Database tutorial data_test-----Create DATABASE Data_testGoUse Data_testGoCREATE TABLE Tb_testt

The impact of using SQL waits blocking on overall performance SQL Server 2000 provides 76 wait types to provide waiting reports. SQL Server 2005 provides an extra 100 wait types to track application

In the last 3 articles, we discussed a list of different queries that reflect the current state of the server. Initial SQL Server performance issues (1/4): Server overview Initial SQL

Is it possible to answer this question in just a few seconds? You may try to view the performance counters in Performance Monitor PerfMon. There are about 1000 counters with different names. You may ask: "Skipped Ghosted Records/sec" number of phantom Records Skipped per second) = 10. Is this value good or bad? The correct answer is that this value may not be important. However, some counters are really imp

" began, and then check the "suo", and then find the word "rope", according to its page, Turn to the page where the word is located. Of course this requires that 1. All Chinese characters in the Xinhua dictionary are arranged in phonetic alphabet order. 2. The Xinhua dictionary has a phonetic lookup appendix in front of it. Clustered index is also the reason, 1. There is a "phonetic" list of all the data, that is, the index. 2. All data is arranged sequentially on the hard disk according to this

can specify whether the event can be "lost". This means that if there is not enough memory to buffer an event, it can be discarded directly. The default setting is to allow a single event to be discarded, but you can also allow the entire event buffer to be lost (for sessions where the event buffer is quickly filled up), or even to specify that no events should be lost.You should take extra care when using the last option, because it forces the code that fires the event to wait until there is e

20150500 Union All Select [Commitid] ,[Authorid] ,[CreatedDate] ,[Createddatekey] fromDb2.tdw.dbo.commits C with(NOLOCK)whereC.[Createddatekey] between 20150500 and 20150900 with Check OPTION; GO 2, query performance test Test1, using the basic table test, cost:16s Select Count (0) from dbo.commits_total C with (nolock) whereDay (c.[ createddate])=1 Test2, using partitioned view test, cost=136s, with Test1 there is a sign

fragmentation has occurred? Execute the following SQL statements in your database. (Sql2005 or earlier database, replace the database name "adventureworks") Select object_name (DT. object_id) tablename, Si. nameindexname, DT. avg_fragmentation_in_percent asexternalfragmentation, DT. avg_page_space_used_in_percent asinternalfragmentationfrom (select object_id, index_id, avg_fragmentation_in_percent, avg_page_space_used_in_percent from sys. dm_db_index

The first time the data is accessed is much slower than the next access, because it reads the data from the disk and writes it to the buffer; Aggregate queries (Sum,count, etc.) and other queries that scan most tables or indexes require a lot of buffering and can adversely affect performance if it causes SQL Server to discard other data from the cache;

performance of the rapid decline.The original version is actually quite common, and performance is better than after the rewrite (in the case of a very long string). But there is also the problem that if the string is too long, the performance drops sharply.If there is really a string of more than 5W commas. This SQL

Tags: max des from work query optimization select Run ASE Query1. Import trace files, such as duration >5000ms, collected by SQL Server profile into the sample table analysis or with the query optimizer advisor 2. You can use the DMV dynamic management view to query analysis SQL Server

Transferred from: http://www.cnblogs.com/MR_ke/archive/2010/08/25/1807856.htmlSQL 2005 Performance TuningSQL Server runs for a period of time, and as data accumulates, SQL runs less efficiently, and in order to use business system normal actions, IT departments often need to spend a high price on SQL tuning experts to

andselectmax(列)(@pageIndexint, --页索引@pageSizeint--页记录数)asbeginsetnocounton;declare @timediff datetimedeclare @sql nvarchar(500)select@timediff=Getdate()set@sql=‘select top ‘+str(@pageSize)+‘ * From tb_TestTable where(ID>(select max(id) From (select top ‘+str(@pageSize*@pageIndex)+‘ id From tb_TestTable order by ID) as TempTable)) order by ID‘execute(@sql)selectd

Many times, the performance bottleneck of our server will be when querying the database, so it is very important to cache the database, then there is no way to implement the SQL Server database cache, when the data table is not updated, read from the cache, when there is an update, only read from the data table, The an

rows reserved data index_size unused TB_WCB 9439661 317208 kb 167168 KB 149872 KB 168 KB */ we found that the size before index compression was 329M. And after compression is 149M, the compression ratio is 45%. The effect is also very obvious. Summarize: Compression through tables and indexes. We can reduce the disk space occupied by the table, this is only part of it, and more importantly, reading the same amount of data, just need to read less data pages,

affected)(One row is affected)SQL Server execution time:CPU time = 0 ms, occupied time = 528 Ms.(Row 3 is affected)Table 'worktable '. Scan count 0, logical read 0, physical read 0, pre-read 0, lob logical read 0, lob physical read 0, lob pre-read 0.Table 'tb2 '. Scan count 3, logical reads 1002, physical reads 0, pre-reads 0, lob logic reads 0, lob physical reads 0, and lob pre-reads 0.Table 'tab1 '. 1 sc

SQL Server query performance optimization-index and SARG (I) For non-SARG statements, SQL SERVER must evaluate each record to determine whether it meets the WHERE clause conditions. Therefore, indexes are usually useless for queries using non-SARG conditions. A non-SARG stat