sql server varchar max performance

Unlike other SQL Server databases, tempdb stops at SQL Server and automatically drops and re-create upon restart. by default, a new 8 MB (MDF file: 8 MB; LDF file: 1 MB, autogtouth is set to 10%) recovery model is a simple tempdb database. After the tempdb database is created, DBA can create data objects, temporary

)Untyped XML is not expressed in XML schema. It is saved as a Unicode string in SQL Server. Storage. For their operations, data needs to be converted to the corresponding type. For example (/book/price) [1]> 19.99, Decimal process. A large number of similar comparisons consume a lot of resources, which leads to the importance of type information in XML schema.Type information works in the following aspects

target_recovery_time = [number of seconds or minutes]As mentioned earlier, SQL Server analyzes the current system pressure and, when it considers that there is no need to checkpoint at this time, kills the process, thus preventing the disk subsystem from becoming worse. When checkpoint is throttled, it is recorded in the information of the Sleep_bpool_flush wait type.Under normal circumstances, this wait s

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

than using cursors. If development time permits, a cursor-based approach and a set-based approach can all be tried to see which method works better. 28. Set NOCOUNT on at the beginning of all stored procedures and triggers, set NOCOUNT OFF at the end. You do not need to send a DONE_IN_PROC message to the client after each statement that executes the stored procedure and trigger. 29. Try to avoid large transaction operation and improve the system concurrency ability. When using constraints and t

SQL Server performance optimization -- wait -- SLEEP_BPROOL_FLUSHPreface: There is a database for historical archiving (referred to as the historical database). After a certain amount of time, the data file has reached more than 700 GB, and it was decided that some data does not need to be retained, this part of data is truncate and more than 600 GB of space is a

] ')This allows you to see the foreign keys in the SalesOrder table (if any)But if so, I do not have to query every table, Google to find a solution, with a SQL statement to do all, as follows:--using Sysreferences--Delete foreign keyDECLARE @SQL VARCHAR( -)DECLARECur_fkCURSORLOCAL forSELECT 'ALTER TABLE ['+ object_name(Fkeyid)+ '] Drop constraint' + object_name(

I. Preface After the new installation of SQL Server 2005/2008, We need to configure SQL Server Based on the Server's hardware and software facilities to achieve better performance. However, the default configuration is used in most cases. Ii. Configuration 1.

perform it during idle time on the server. after repeated tests, after, the server maintenance job has not run yet, and the user has been off duty, even if each contraction is 100 GB, it only takes more than one hour. Despite the unsatisfactory results, readers may want to see how to solve the problem thoroughly. However, it is a formal environment and cannot be easily tried or modified. However, in additi

Use Windows performance monitor to monitor common SQL Server metrics As mentioned in the above article, Win's Performance Monitor is an essential tool for monitoring database performance. Next I will introduce some common monitoring metrics, which are nothing more than disks

DC--perform connection, most recently executed query informationCross apply sys.dm_exec_sql_text (dc.most_recent_sql_handle) DTJoin Sys.dm_exec_sessions DS on dc.session_id=ds.session_idwhere Ds.login_name= ' LCGS609999 '--where ds.program_name = '. Net SqlClient Data Provider 'ORDER by Dt.textCopy Code Copy Code--Clears all cached data in the buffer poolDBCC dropcleanbuffersGO--Clears all cached execution plans in the buffer poolDBCC FreeproccacheGO--statistical information, implementation pla

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 design. Redundancy can be a redundant databa

, and spikes in CPU and memory resource consumption occur on the server. System structure The performance problem stems from the whole structure and development process of the system. The application of the Olite system is a Web Form program based on the. NET platform, and the database is SQL Server 2005. Its main stru

Label:The above article mentions that win's performance Monitor is a necessary tool to monitor database performance, and then I will introduce some common monitoring indicators, in fact, the disk, CPU, memory and other hardware operating indicators and the database itself like the lock Ah, the number of user connections Ah, There are parameter indicators that need attention according to their own business d

SQL Server query performance optimization analysis transactions and locks (I) SQL Server query performance optimization analysis transactions and locks (ii) SQL

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

data, the same query in different circumstances may produce the opposite result, how to apply well is mainly in our personal understanding and understanding, hope to see this article friends can deepen some understanding of the index and understanding , and get rid of the error of index and develop high performance application. I am not a DBA, just a common developer, the above are some of the actual work experience, experience, in view of my level i

twice times the number of processors, you canA CPU bottleneck can occur because the processor is too late to process the request.You can use the Processor Queue length and% Processor time counters to determine if there is a CPUBottleneck. If both are outside the acceptable range, there must be a CPU bottleneck.If the Processor Queue length is not within the acceptable range, but the% Processor time in acceptable fan, there may not be a CPU bottleneck, but there is a configuration problem. Need

Label:Reprint Link: http://www.cnblogs.com/knowledgesea/p/3683505.htmlOverview of ToolsIf you have a database application system, there are a large number of tables, views, indexes, triggers, functions, stored procedures, SQL statements, and so on, and the performance of the poor, and the bitter you have to optimize it, then what should you do? Brother teaches you, first you need to know where the problem i

to pssdiag is as follows: Pssdiag is a general purpose diagnostic collection utility that Microsoft Product Support Services uses to collect various logs and data files. pssdiag can natively collect performance monitor logs, SQL profiler traces, SQL Server blocking Script output, Windows event logs, and sqldiag output