top 10 optimizer

Label:Original: SQL Server optimizer features-dynamic retrievalSome time ago I wrote the article SQL Server implicit conversion caused by lying gun deadlock in some friends commented back said that in the SQL2008R2 test did not appear deadlock, their own measurement is true, so to everyone to bring the doubts expressed sorry, I'll explain the reason here. Review: The cause of the deadlock in SQL2012 has been explained, because the table scan caused

Oracle optimizer has two optimization methods: Rule-Based Optimization (RBO) and cost-based optimization (cost-based optimization, (for short, CBO). In oracle8 and later versions, the CBO method is recommended for Oracle strong columns.RBO mode: when analyzing SQL statements, the optimizer follows some predefined rules in Oracle. For example, we usually use indexes when a column in a where clause has an ind

All databases perform query optimization on SQL statements. What is the process like? First, the query optimizer uses the equivalent rule system to generate an expression equivalent to the given expression. In terms of concept, a new expression is generated when the expression matches one side of the equivalence rule. To reduce the space requirement, most optimizers will point the expressions with common subexpressions to the shared subexpressions.

Many small dishes that have just started linux and like Centos won't compile Zend Optimizer. Here I will teach you how to yum install Zend Optimizer. Haha, thank you ~!First enter and run: wget-q-O-http://www.linuxidc.com/system/systemfiles/2010/12/atomic.sh | shThen run the command: yum install php-zend-optimizer!First, you need to download the RPM Repository of

As we all know, the drivers on the computer, like other files on the system, can be compromised and run out of control, perhaps to reinstall or upgrade the driver. In daily life, before we reinstall the operating system, we may not be able to find a NIC or modem driver, fearing that the network device could not be installed. Now it's easy, and Windows tuning Guru provides the ability to drive smart backups. Here, let's look at how Windows Optimizer Ma

　　 Some time ago with a blog several test pages to try the use of Google Website optimizer to do A/b test, after this time to collect some test data, thank you for your help click. In fact, always wanted to introduce Google this site Contrast experiment optimization tools, completely free and easy to operate, and in the near future, independent of Google Website Optimizer will disappear, this pie

This article describes how to use an optimizer to improve the execution efficiency of Python programs, including writing timers and using built-in Optimizer, if you need a friend, it is unwise to start optimization without first thinking about the famous saying of Knuth. However, you can quickly write code that adds some features, which may be ugly. you need to pay attention to it. This article is prepared

In Apach, Zend Optimizer and Xdebug are loaded with dynamic libraries through zend_extension_ts; Then if you use Zend Optimizer and xdebug at the same time will be error; Then find a way to copy Php_xdebug-2.1.2-5.2-vc6.dll to ext, with the following method to solve, but still not normal loading xdebug; So I want to ask you how to solve the great God!! Thank you very much!! Extension=php_xdebug-2.1.2-5.2-

Zend Optimizer's problem? Zend Optimizer on the official website said outdated, included in the 5.3 version above, ask now PHP also use optimizer? How to use it? Zend Optimizer How to use this too? ------to solve the idea---------------------- Zend Optimizer is a PHP performance enhancement tool developed by Zend. At t

three parts. Now it's all done:Memory Introduction, Recoken (calculation) See :android Memory Optimizer (large rollup--on) reduce (decrease), reuse (reuse) See :Android Memory Optimizer (large rollup--medium) Recycle (recycling), Review (check) See :android Memory Optimizer (big summary-full) The purpose of writing this article is to make a large summary, the

Label:Reference: http://codingstandards.iteye.com/blog/1344833 In the above reference article, "High performance MySQL," fourth chapter fourth section in the third edition of my corresponding chapter sixth Chapter fifth section Recently analyzed the production environment slow query, found a long time but inefficient query MySQL version 5.5.18 SELECTLoc.cell_no asM_cellno ... fromBs_loc Loc Left JOINSt_stock_m m onLoc.cell_no=M.cell_noWHERE 　　　　　　Loc.zone_no= 'B12' andL

MySQL has provided the optimizer Option Switch option since 5.1. In this way, we can force some things that we think should not be done when the optimizer is confused, or when we want to see why the optimizer is so selective, you can manually disable or enable these options to change the optimization policy.In MySQL 5.1, the following switch is added:MySQL 5.5 ad

Solve the problem related to the Optimizer in the MySQL database. MySQL uses an overhead-based optimizer to determine the optimal solution for processing queries. In many cases, MySQL can calculate the best possible query plan, but in some cases, MySQL does not have enough information about the data and has to make a "educated" estimation of the data. When MySQL fails to do "correct", you can use the fol

By now, Zend optimizer's current versions are 3.3.3 (Windows) and 3.3.9 (Linux), and php5.3 and later versions are not supported. Many of my colleagues, including myself, have always been able to use php5.2 only by B. Of course, because Dede has poor support for php5.3, there is no way to stop at the 5.2 era. According to the official statement, this has always been the case: due to too many upgrades to php5.3, after ZP is updated, it will no longer be compatible with PHP files encrypted by Zeng

Direct Download Address: http://cn2.php.net/distributions/php-5.2.8-win32.zip 2, MySQL recommended MySQL 5.0.67 Windows Zip/setup.exe (x86) versionMd5:ed76e5ad8b251ca643766c70926854d7Official download page:http://dev.mysql.com/downloads/mysql/5.0.htmlHttp://dev.mysql.com/get/Downloads/MySQL-5.0/mysql-5.0.67-win32.zip/from/pickDirect Download Address:http://mysql.cs.pu.edu.tw/Downloads/MySQL-5.0/mysql-5.0.67-win32.zip 3, Zend Optimizer recommend

Iis+php+mysql+zend OPTIMIZER+GD Library +phpmyadmin installation configuration [Full revision utility] First, software preparation: The following are the latest official version as of 2006-1-20, the download address is also valid for a long time1.PHP, recommended PHP4.4.0 zip version: PHP (4.4.0): Http://cn.php.net/get/php-4.4.0-Win32.zip/from/a/mirror PHP (5.1.2): Http://cn.php.net/get/php-5.1.2-Win32.zip/from/a/mirror 2

) Router settings Router A settings: (if Router A is already set up, the following settings for router A can be skipped) Connect your computer's network cable to the LAN port of Router a Download and install the Master route optimizer on your computer-Advanced settings-Internet settings-dial-up Internet (ADSL) Enter your online account and password in the Internet settings Router A is set up, at this time the computer can be internet Router B se

Without a statement, speak directly:The federated index in the Babysitter_account table is as follows (developing a federated index that the small partners have built themselves, did you find it inappropriate?) ）：KEY ' flag ' (' flag ', ' user_id ', ' account_id ')Used to think:1.SELECT Account_id,weibo_id,weibo_type from Babysitter_account WHERE user_id between and 10000 and flag=0;2.SELECT Account_id,weibo_id,weibo_type from Babysitter_account WHERE flag=0 and user_id between and 10000;The fir

Case code: #建立抽象模型x = Tf.placeholder (Tf.float32, [None, 784])y = Tf.placeholder (Tf.float32, [None, ten]) #实际分布的概率值w = tf. Variable (Tf.zeros ([784, 10])b = tf. Variable (Tf.zeros (10))A = Tf.nn.softmax (Tf.matmul (x, W) + b) #基于softmax多分类得到的预测概率#定义损失函数和训练方法Cross_entropy = Tf.reduce_mean (-tf.reduce_sum (Y * tf.log (a), reduction_indices=[1])) #交叉熵Optimizer = T

The problem of Count and index coverage in the MySQL optimizer indicates that an optimizer still needs to be improved. Based on the where condition and the fields in select_list, the optimizer determines whether to return to the clustered index to retrieve data after an index (sta) is used. The basic practice is to determine all the fields in select_list and wher