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The following articles mainly summarize the practical application skills of the Oracle explain plan. If you need to optimize the SQL statements in the Oracle database, we need to know the relevant plans to be executed, so as to make targeted adjustments. There are several methods to obtain the Oracle execution plan, which will be summarized below. 1. Use of EXPLAIN Every SQL statement executed by the Oracle

Someone recently proposed to view the Postgresql execution plan. The following describes how the cost and other related values in the PG execution plan are calculated:PG version 9.1.21. Use the terminal tool PGADMIN to press F7 to execute the statement, and then view the data output and explanation. 2. Command Line Analysis: explain select * from table_name;Generally, we will pay more attention to the cost

Tags: official study www tar cut show execution mat styleSQL Server execution planning (execution plan) Introduction Outline: Objective to describe the approximate use of execution plans in SQL Server, which can be useful when a query performance bottleneck is encountered, and with a more detailed learning document and plan, which the reader can follow as I plan

based on specific queries, and of course you can create statistics manually.First, to intuitively understand what the statistics look like, reference, that is,_wa_sys_**** begins with the statistics that the system creates as needed,The same name as the index is the statistics created on the index,Manually creating statistics can also be self-named in cases where SQL Server naming requirements are met.　　The following is the statistical information for the index.　　　　The role of statistical infor

MySQL execution Plan explain detailed 2015-08-10 13:56:27Category: MySQLThe explain command is the primary way to see how the query optimizer decides to execute a query.This feature has limitations and does not always tell the truth, but its output is the best information that can be obtained, and it is worth taking the time to understand, because you can learn how the query executes.Call explainAdding Explain,mysql before select sets a tag on the que

Label:A. Prepare a plan "Note": 1, first activate SQL Server Agent service 2., transaction records (only for full and large records of the original mode). 3, the following "clear spare trn file" "clear up the journal file" did not make plans to explain Second, through the design of the refinement plan "Note": There are several different schedules for the bread in the previous

Preface: This series of articles includes: 1, understand the hash, Merge, Nested Loop Association strategy. 2. Find and resolve table/index scans in the execution plan. 3. Introduce and find keys to find and resolve them in the execution plan. For performance optimization, the following issues need to be centrally addressed: 1, create a performance baseline for your environment. 2, monitor the current per

How to read ORACLE Execution Plan First, what is the implementation plan An explain plan is a representation of the "access path" is taken when a query is executed within Oracle. second, how to access data At the physical level Oracle reads blocks of data. The smallest amount of data read is a single Oracle block, the largest are constrained by operating syste

Add UserThe first step you want to do every JMeter test plan is to add a Thread Group element. The thread group tells JMeter the number of users you want to impersonate, how long the user should send the request, and how many requests they should send. continue adding Threadgroup elements first select the test plan, click your right mouse button Add a menu, then choose add a?? threadgroup . You should n

SQL Server maintenance plan for database backup (step by Step)First, PrefaceSQL Server Backup and restore all -in-a-kind, including the use of SSMS operation to restore a variety of backup files graphical guidance,SQL Server Database Minimum outage migration scenario , which uses SQL script (T) to complete a full backup, Differential backup, full restore, differential restore, etc.; with the above foundation, we joined the database backup elements, th

educating users and teaching users to manage time are as follows, it is more important and has more long-term significance than simply meeting users' actual needs. Week Plan is a time management and team collaboration tool recently developed by an Australian startup team. We have made special reports on tools of the same type, including Asana, trello, Evernote, teambition, partners in China, zapier, fleep, processon, and so on. Compared with the boss

Label: style blog HTTP color OS ar use strong sp The basic purpose of plan buffering is to improve performance by reusing the execution plan. It is important to confirm that the execution plan is reusable. Because the reusability of ad hoc queries is inefficient, we recommend that you use predefined workload technologies as much as possible. To ensure the effic

These terms in the predicate information sections indicate when the data source is reduced. Simply, access means only retrieve those records meeting the condition and ignore others. Filter means *after* already got the data, go through them all and keep those meeting the condition and throw away the Others.Access: Get the data that meets the criteria directly, discarding other unsatisfied dataFilter: You already have some data to apply filter to the existing data to get the data that satisfies t

Tags: style c int a data use1. The optimizer (Optimizer) is an optimization tool for SQL analysis and execution that is responsible for making the SQL execution plan, which is responsible for ensuring that SQL performs the most efficiently, such as determining how Oracle accesses the data, full table scan, or index range Range scan), or full index quick Scan (index fast, index_ffs), and how the query is associated with the table. There are 2 kinds of

Oracle11g recursion + exists Execution Plan Change There is a recursive query that runs fast on 10g, but cannot run on 11g.SQL> select * from v $ version;BANNER--------------------------------------------------------------------------------Oracle Database 11g Enterprise Edition Release 11.2.0.4.0-64bit ProductionPL/SQL Release 11.2.0.4.0-ProductionCORE 11.2.0.4.0 ProductionTNS for Linux: Version 11.2.0.4.0-ProductionNLSRTL Version 11.2.0.4.0-Productio

A business plan is a carrier that finally implements many entrepreneurial ideas in the dark.How to write a business plan? Depending on the purpose, the objects of the plan are different. Do you want to write the plan to investors or take a bank loan for different purposes? The focus of the

1. Improve communication skills. In the past few months, I have been deeply impressed with my lack of communication skills. I plan to improve my communication skills through the following aspects: (1) fully learn from colleagues, such as morning meetings, emails, requirement clarification, and brainstorming. These are not only the processes of learning technology and business, I also need to learn other people's expressions and skills during this peri

Some people often ask me, "I have $10 thousand for investment. What do you suggest me to invest ?" My standard answer is: "Do you have any plans ?" A few months ago, I made a program on a radio station in San Francisco. The program was invested by a popular local securities broker. An audience member who wanted investment advice called and said, "I am 42 years old and have a good job, but I have no money. My mother has some property rights for a house, and the suite is worth about $0.8 million.

SQL Profile provides other information except system statistics and object (table and index) statistics for an SQL statement, such as the running environment and more accurate statistics, to help the optimizer select a more suitable execution plan for SQL statements.SQL Profiles can be said to be the evolution of Outlines. The functions that Outlines can implement can also be fully implemented by SQL Profiles, while SQL Profiles have optimizations tha

English Original: Technical debt:a Repayment Plan　　What is technical debt?Many teams are plagued by technical debt, but few teams can really design a plan to break free from it. In order to better understand how to get rid of debt, we first have to correctly understand what is technical debt.Technical debt is incurred by teams who deliberately make poor technical decisions for short-term project benefits. F