improve linq query performance

ASP. NET has many secrets. When you understand these secrets, you can make your ASP. NET applicationProgramThis greatly improves the performance. For example, when using membership and profile for authentication and authorization, you can simply modify membership and profile to Improve the Performance of authentication and authorization. asp.. Net HTTP pipeline t

named Table14. The CTE can refer to itself, or it can refer to a pre-defined CTE in the same with clause. Forward references are not allowed.5. The following clauses cannot be used in CTE_query_definition:(1) COMPUTE or COMPUTE by(2) ORDER by (unless the TOP clause is specified)(3) into(4) OPTION clause with query hint(5) for XML(6) for BROWSE6. If the CTE is used in a statement that is part of a batch, then the statement before it must end with a se

Tags: type error associated recommendation management will rom Ora no(Transferred from http://blog.csdn.net/sforiz/article/details/5345359) We have to do not only write SQL, but also to write good performance of SQL statements.(1) Select the most efficient table name order (valid only in the rule-based optimizer):The Oracle parser processes the table names in the FROM clause in a right-to-left order, and the FROM clause is written in the final table (

MySQL is more and more used in database applications because of its small size and efficient operation. I used to develop a peer-to-peer application of the use of MySQL to save Peer-to-peer nodes, due to peer-to-peer applications, knot points are tens of thousands of times, and node changes frequently, So be sure to keep the query and insert efficient. Here are three effective attempts to improve efficiency

Introduction Asp.net has many "secrets" worth exploring. When you discover them, it will greatly improve the performance and scalability of your website! For example, for membership and ProfileProgramThere are some secret bottlenecks that can be easily solved, making authentication and authorization faster. In addition, the HTTP pipeline of Asp.net can process each request to prevent execution of unnecess

OscacheCharacteristicsCache any object, you can cache portions of JSP pages or HTTP requests without restriction, and any Java object can be cached.Having a comprehensive Api--oscache API gives you a comprehensive program to control all the Oscache features.Persistent caching-caches can write to the hard disk at will, so it allows expensive creation (expensive-to-create) of data to keep the cache, even allowing the app to restart.Support cluster--the cluster cache data can be configured by a sin

Introduction Asp.net has many "secrets" worth exploring. When you discover them, it will greatly improve the performance and scalability of your website! For example, there are some secret bottlenecks for Membership and Profile providers, and they are easily resolved, making authentication and authorization faster. In addition, the http pipeline of asp.net can process each request to prevent attacks by exe

Experience how MySQL indexes improve search performance 1. Create a user table that contains two columns: name and phone2. Use python (any language you like) insert records (the lz notebook is old, it takes about 1 minute ):#! Usrbinenvpython #-*-coding: UTF-8-*-importMySQLdbconnMySQLdb. connect (hos Experience how MySQL indexes improve search

of page splits and improve performance. Compress backup option: In Server backup, compress is used to reduce IO, but CPU operations are increased. (4). Connection Maximum number of concurrent connection: sets the Maximum number of connections. Use query governor prevent long-running queries: Use the query manager to b

Creating an index on a database will negatively affect the database. When you insert, update, and delete a table, you will see a negative impact on this performance. Each time you make a modification to the table, the indexes that contain the modification records must be updated to comply with the latest modification. After filtering indexes, the number of indexes to be updated is reduced. However, indexes containing these records still need to

The original love coding, will program the nuclear power engineer. Personal blog Address: zhihu.com/people/zhong-yun-75-63Learn some tricks to maximize the performance of Python programs and avoid unnecessary waste of resources.1. Using Local variablesTry to use local variables instead of global variables: Ease of maintenance, improved performance, and memory savings.Use local variables to replace variables

The company has a PHP project, but it finds that the concurrent access volume and security of the project are not very good when going online. now the boss gives me the task, let me see if there is any way to improve the concurrency of the project in java, but I have been working for more than a year and I am not very familiar with the performance, the nginx + apache + php mentioned in the online

about 7 s before optimization, the first 0.3 s after optimization, and the second 0.1 s after optimization.We can see that the disk I/O is the performance bottleneck before optimization, and the SSD speed is much faster than SATA. After optimization, the disk is no longer the bottleneck, and there is no difference in SSD and SATA performance. On the Linux platform, the/tmp directory is used by default. N

driver A table, a Just to be interviewed 20 times, its performance is conceivable. 2, do not use in+ subquery Note that I do not say that you do not use in query, if the value in is given. Instead of making queries from other tables through Select, it is understandable to use Inkeyword, but if the data in is obtained from other tables by Select, it is strongly recommended that you change it to

Server | static | performance | page uses a "Static" ASP page to improve the performance of your server Usually, when you display the information in a database, you use a dynamic page to generate it. This has no effect on the performance of a small web site or when the size of the database is not large. But when users

There are many solutions, but the Libevent library and the Libev library can greatly improve performance and event handling capabilities. In this article, we discuss the basic structures and methods used to use and deploy these solutions in UNIX® applications. Both Libev and libevent can be used in high-performance applications, including applications deployed in

complete the same function. 11, the Str_replace function is faster than the Preg_replace function, but the efficiency of the STRTR function is four times times the Str_replace function. 12, if a string substitution function, can accept an array or character as a parameter, and the parameter length is not too long, then you can consider an extra piece of replacement code, so that each pass argument is a character, rather than write a line of code to accept the array as the

column value for each row, so it is required to perform clustered index scan.SoSelect * from [tablename] Where pk in (select top 1 PK from [tablename] order by newid ())It should be comparableSelect top 10 * from [tablename] order by newid ()More Io consumption. However, if you create another non-clustered index for the primary key, it will be different.Create index ix_pk on [tablename] (PK) In this case, the number of pages of a non-clustered Index containing the pkvalue is much smaller th

ObjectiveIn a project, the unity of technology is the most important, the database design is the focus of the emphasis. NoSQL is currently the most popular database, but its practicality and functionality are far less useful than SQL database.Many of the real-world SQL database is criticized for the performance of most of the problem stems from the programmer's unreasonable design, a good design can make SQL class database to

Old wine New bottle--Change the angle to improve the performance and quality of the APPSpeaker: Gaoliangliang---Hungry? Mobile Technology Senior iOS engineer, responsible for hungry? Business Edition iOS app development, deep research on architecture and system bottom, good at mobile performance analysis, trouble shooting,ios reverse programming.Speaker Time: 201