Tag：Level
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Time：2021-4-19
Transaction isolation level What is a business? A transaction is a logical set of operations, either executed or not executed. The most classic example of transaction is transfer. If Xiaoming wants to transfer 1000 yuan to Xiaohong, the transfer will involve two key operations: reducing the balance of Xiaoming by 1000 yuan and increasing the […]
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Time：2021-4-18
Deepdraw intelligence is a company engaged in interdisciplinary research in the field of artificial intelligence and aesthetic design, driven by technological innovation. Its headquarters is located in Binjiang District, Hangzhou City, Zhejiang Province. The main products of deep drawing intelligent company are deep drawing Detail Art robot, which is an artificial intelligence system for e-commerce. […]
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Time：2021-4-11
It’s said that there are many people who are popular. I wonder if you still remember that the popular song “wolf disco” in 2019 was involved in plagiarism and even sent a lawyer’s letter.Of course, this matter has been solved, and my uncle has proved his innocence. But the original author’s protection of his music […]
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Time：2021-4-10
In the last article, we talked about MariaDB’s locks, and how to manually lock and unlock them. Please refer to the review https://www.cnblogs.com/qiuhom-1874/p/13196905.html Today, let’s talk about the transaction isolation level of MariaDB. In the previous essay, we mentioned the storage engine of MySQL, including MyISAM and InnoDB, where MyISAM does not support transactions and […]
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Time：2021-4-7
The main contents of this paper are as follows Create a basic log class to output the log to the console and write to the file at the same time Create a student class. The score property can only be an integer. Instantiate the student class and assign different values to score to verify the […]
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Time：2021-4-6
catalog Four characteristics of database transaction (1) atomicity (2) consistency (3) isolation (4) durability Four isolation levels of SQL Read uncommitted Read committed Repeatable read Serializable (serializable) Set transaction isolation level of MySQL windows: Linux Four characteristics of database transaction This article talks about the four characteristics of transactions in database (acid), and will explain […]
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Time：2021-3-18
import pandas as pd import numpy as np #Line chart s=pd.Series(np.random.randn(10),index=np.arange(0,100,10)) s.plot() <AxesSubplot:> df=pd.DataFrame(np.random.randn(10,4),index=np.arange(0,100,10),columns=list(‘ABCD’)) print(df) df.plot() A B C D 0 -0.358499 1.242513 -1.200230 0.218051 10 -1.540113 -0.344976 -1.509415 1.162260 20 0.680961 0.398406 -0.429856 1.027732 30 0.545883 -0.101128 1.747935 0.423187 40 0.763575 -0.682698 0.885915 0.796835 50 -2.419253 -0.794231 -1.100932 -0.309591 60 1.212027 0.684612 -0.035615 0.999927 […]
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Time：2021-3-17
About Apache pulsar Apache pulsar is Apache The top project of software foundation is the next generation cloud native distributed message flow platform, which integrates message, storage and lightweight functional computing. It adopts the architecture design of separation of computing and storage, supports multi tenant, persistent storage, multi machine room and cross regional data replication, […]
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Time：2021-3-13
1. What is the index?Index is a kind of data structure, similar to the catalog of books, which can help to find data quickly. 2. What kind of data structure is index?In InnoDB engine, the data structure of index is B + tree and hash index 3. What are the differences and disadvantages between hash […]
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Time：2021-3-12
Windows Apache log extraction and security analysis 1、 Apache log introduction: 1. The access log function of Apache is controlled by mod_ log_ The log format is (CLF) common log format. 2. Eight levels of Apache log: emergency, alert, crit, error, warn, notice, info and debug. Emergency: the system is unavailable in case of emergency […]
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Time：2021-3-11
Author: afanlusource:http://www.cnblogs.com/luxiaoxun/ 1、 What is high concurrency High concurrency is one of the factors that must be considered in the design of Internet distributed system architecture. It usually means that the system can process many requests in parallel at the same time by design. Some common indicators related to high concurrency are response time, throughput, […]
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Time：2021-3-9
Overview of exception and error in version 7.2 What is an exception? Exception refers to the situation that the program does not meet the expected situation and is different from the normal process. For example, if you link to a database and write all the parameters, you will find that the link does not go […]
