at t deaf plan

1 Overview The essence of SQL is a series of pseudo-code, which expresses what is done, not what it means. Like other languages, SQL statements must be compiled before they can be run. Therefore, each SQL statement must be interpreted by the compiler before it can be run (SQL optimization is required ). These steps all require running costs, so there is a thing in the database called the execution plan, the compiler will save the compiled SQL into the

1. What is the execution plan Anexplainplanisarepresentationoftheaccesspaththatistakenwhenaqueryisexecutedwithin 1. What is An explain plan is a representation of the access path that is taken when a query is executed 1. What is an execution plan? An explain plan is a representation of the access path that is take

Oracle constraints (constraints) affect the query plan, oracleconstraintsOriginal article: http://www.oracle.com/technetwork/issue-archive/2009/09-may/o39asktom-096149.htmlHow constraints in oracle affect the query planIt is generally considered that the constraints are only related to data integrity. However, the constraints are also used by the optimizer to optimize the execution plan.The optimizer takes the following resources as the most input inp

Source: What caused that "go horribly" wrong–should you update statistics? Since I did encounter such problems, but based on the level and experience, do not intend to repeat the wheel, so Daniel's article translated for your reference. The following is the translation: In the past few years, I have encountered such situations: There is a stored procedure that runs very well for most of the time, but suddenly it doesn't. There is a cliff-type decline in performance. You don't know why, but someo

You can use the 10046 event to view the execution plan in the Oracle database and get the logical read, physical read, and time consumed by each execution step in the SQL Execution Plan. This You can use the 10046 event to view the execution plan in the Oracle database and get the logical read, physical read, and time consumed by each execution step in the SQL Ex

[NOIP2015] Transport plan D2 t3descriptionIn the 2044 A.D., humans entered the cosmic era.L State n Planets, there are n-1 two- way waterway, each channel is built between two planets, this n-1 waterway connected to all the planets of L country.Little P is in charge of a logistics company, which has many transport plans, each of which is a logistics spaceship that needs to fly from the UI number Planet to Planet VI. Obviously, it takes time for the s

The Xixiang program was finally completed. Since the kernel module was unable to be downloaded, I had to write it myself. After understanding the principle of the Xixiang program, writing this module is not very troublesome (in fact, it is not simply to write the module, but to directly modify the kernel protocol stack Code). let's first talk about the principle and then talk about the kernel modification suggestions. Sequence. Xixiang plan The Xixian

Career planning is the trend of the new era. The subject of modern people, the sooner they plan, the better they will be, the bigger the odds are. The more old they get used, the more they will not only make their career plans early, let yourself live a happy life, and be your children, students, and employees, lighting their careers and helping them guide their proper development. Career planning tips 100, from Jiang wenxiong: In his book career plan

There are many ways to view the SQL Execution Plan. 10046 events are one of them. different from other SQL Execution plans, when we encounter complicated SQL statements, we can track SQL statements through 10046 to obtain the logical reads of each step in the execution plan, physical read and time spent. this fine-grained tracking is SQL-oriented for our analysis. There are many ways to view the SQL Executi

Recently, reviews of planning documents are always available. You can write it yourself, read it by others, and help people make suggestions. These planning questions include the future language planning, public resource management planning, and industrial development planning of the company. However, planning is probably one thing that requires three or even five years of development in advance. Plan a general goal and then point out a route so that

Copyright Disclaimer: During reprinting, please use hyperlinks to indicate the original source and author information of the article and this statementHttp://zlfoxy.blogbus.com/logs/16785336.html 7. Create a database test plan In this section, you will learn how to create a basic test plan to test a database server. you will create ten users to send 5 SQL requests to the databas

Now let's talk about the meaning of each parameter in the Oracle execution plan. The following is an example. Here is a supplement.: Trace types: Serial number Command Explanation 1 SET AUTOTRACE OFF This is the default value, that is, disable Autotrace. 2 SET AUTOTRACE ON EXPLAIN Show only execution plans 3 SET AUTOTRACE ON STATISTICS Only statistics of execution are displayed. 4

More and more enterprises use content management systems to manage structured or unstructured data such as electronic invoices, electronic documents, and human resources, and outsource these businesses to third-party IT companies. Outsourcing companies, or existing content management systems, cannot meet business growth, performance, compatibility, and other needs, the company plans to adopt business management, performance and compatibility better systems. At present, some enterprises do not ad

4326:NOIP2015 Transport Plan Time limit:30 Sec Memory limit:128 MBsubmit:703 solved:461[Submit] [Status] [Discuss] DescriptionIn the 2044 A.D., humans entered the cosmic era. L State n Planets, there are n−1 two-way waterway, each channel is built between two planets, this n−1 waterway connected to all the planets of L country. Little P is in charge of a logistics company, which has many transport plans, each of which is a logistics spaceship