capital one optimizer

do not know whether the execution efficiency of the above two statements is the same, because if it is simple from the statement, the two statements are indeed different, if the TID is an aggregate index, then the last sentence only from the table of 10,000 records after the row , and the previous sentence to look at the whole table to see a few name= ' Zhangsan ', and then based on the constraints of conditions tid>10000 to propose the results of the query.In fact, such worries are unnecessary

There are three types of Oracle optimizer, rule (based on rules), cost (based on costs), and choose (selectivity), which we all know to set the default associated Oracle optimizer, which can be passed to the Init.ora file Optimizer_ Various declarations of the mode parameter.such as Rule,cost,choose,all_rows,first_rows. You can certainly overwrite it at the SQL sentence level or at the session level.In orde

Zend optimizer is used to optimize php code. During php Execution, after the php file is read from the disk to the memory, the code in the php file should be compiled to generate OPCODE, then Zend engine runs the Opcode. Zend Optimizer is used to optimize the compiled OPcode. Originally, I wanted to install it on Ubuntu. Unfortunately, ZO does not support 5.3 for the time being, so I had to install it on Ce

Query optimizer of MySQL Query optimization series (1) when you submit a query, MySQL will analyze it to see if some optimization can be done to make it faster. This section describes how the query optimizer works. If you want to know the optimization methods used by MySQL, you can refer to the MySQL Reference Manual. Of course, the MySQL Query optimizer also us

Welcome to the Linux community forum and interact with 2 million technical staff to access MySQL from 5.1 and provide the switch options for optimizer options. In this way, when the optimizer is confused, we can disable something we think should not be done; or when we want to see why the optimizer needs to be selected, We can manually close or press Welcome to

The oracle optimizer uses statistics to select the optimal or sub-optimal execution plan. During the execution plan determination process, oracle can analyze the data distribution characteristics of each table column very well, however, oracle is powerless for some associations between columns, such as the correspondence between city names and zip codes. Fortunately, the statistical analysis Feature Based on column combinations and relational expressi

Zendchina official: The following describes the installation method for Zend Optimizer 3.3 in a Linux environment. This article is a Linux system based on the RHEL5 architecture.(1) Installation of Zendoptimizer 3.3.3 version.Zendoptimizer 3.3.3:Http://down1.chinaunix.net/distfiles/ZendOptimizer-3.3.3-linux-glibc23-x86_64.tar.gzInstallation:# wget http://down1.chinaunix.net/distfiles/ZendOptimizer-3.3.3-linux-glibc23-x86_64.tar.gz# TAR-ZXVF Zendoptimi

Label:In MySQL5.6, it is supported to record the query plan tree of the SQL being executed, and for the time being, even for very simple queries, a lengthy query plan may not seem very readable, but for an experienced DBA who knows more about the query plan's build process, this is an optimized SQL treasure, because exposure A large number of internally generated query plan information to the user, which means that we can optimize the cost of the larger part.The new parameter optimizer_trace can

Tags: optimizerWe know that in the process of parsing SQL statements, there is a process called optimization. Oracle has a component called optimizer specifically designed to handle SQL optimizations. After considering many of the factors related to query conditions and object references, the optimizer can determine the most efficient way to execute an SQL statement. For any SQL statement, the

The following article describes how to use optimizer updates to execute plans in DB2 databases, we all know that in a DB2 database, the optimizer is generally used to analyze SQL statements and generate an Access Plan that is considered optimal ). The DB2 optimizer is actually a set of standard rules. Generally, we only need to tell DB2 what to search, not how to

Original: SQL Server optimizer attribute-implicit predicateAs we all know, a SQL statement submitted to the optimizer produces a corresponding execution plan and then executes the output, but how does his execution plan come about? This may be the most complex part of a relational database. Here I'll introduce you to an attribute of the SQL Server optimizer-the i

Welcome to the Oracle community forum and interact with 2 million technical staff. When the WHERE clause uses a function for a column, unless this simple technology is used to force the index, otherwise, the Oracle optimizer cannot use indexes in queries. Generally, if the WHERE clause does not use functions such as UPPER, REPLACE, or SUBSTRD Welcome to the Oracle community forum and interact with 2 million technical staff> Go To The WHERE clause to u