An example of ASM disk not found in DBCA Library

Environmental Information red hat linux64  gi 11.2.0.4  oracle 11.2.0.4 Problem Phenomena After installing gi software and oralce database software, the database is built through the dbca user interface. It is found that the database can be built normally on node1, not on node2. The dbca library building process errors on node2. Figur ...

Posted by scottrad on Sun, 05 Jul 2020 17:42:16 +0200

Use of SQL Statement - Database Operation

[select] SQL statement query join(left/right) two-table join/multi-table join //Multi-table Joint Survey: $sql = 'SELECT * FROM news LEFT JOIN (news_type, news_photo)ON (news_photo.n_id=news.n_id AND n_type=news_type.id)'; //Joint investigation of two tables: $sql = 'SELECT * FROM s LEFT JOIN sc ON s.sno=sc.sno'; Three Tables Joint Ch ...

Posted by gawrrell on Sun, 05 Jul 2020 17:37:13 +0200

[source code analysis] Oozie history submission task

0x00 summary Oozie is an open source framework based on workflow engine contributed by Cloudera company to Apache. It is an open source workflow scheduling engine of Hadoop platform, which is used to manage Hadoop jobs. This article, the first in a series, introduces oozie's task submission phase. 0x01 problem We deduce the implementation f ...

Posted by cowboy_x on Tue, 30 Jun 2020 05:26:29 +0200

Singleton singleton mode

Singleton mode is one of the creation modes. In our software development process, there are many classes that are only created once globally, such as app framework class, global management class, configuration file, log, database, etc. Using singleton mode can make our code elegant. The UML class diagram and C++ sample code are given below: ...

Posted by mightymaster on Mon, 29 Jun 2020 18:15:58 +0200

Backup private key for MAC decentralized wallet development

1, Private key   in this lesson, we will continue to register the Token, which is to backup the private key. Each public chain will have a private key, but it is different. There are four private keys in MAC. namely Wallet Key Wallet key is one of the necessary information to open MAC wallet. ...

Posted by doodmon on Mon, 29 Jun 2020 10:36:56 +0200

Chapter 13: concurrent deadlock and enterprise solutions (deadlock, livelock, starvation)

1. What is a deadlock? What's the harm? 1.1 what is deadlock? Occurs in concurrency [mutually exclusive]: when two (or more) threads (or processes) hold each other's resources required by each other, but do not actively release them, all of them can't move forward, resulting in endless blocking o ...

Posted by ollmorris on Mon, 29 Jun 2020 08:23:19 +0200

Hand in hand to teach you to customize a Druid Filter to record sql, and combine Nacos to realize dynamic switch and judge threshold adjustment

1, Background Durid is a widely used database connection pool, which has superior performance, powerful monitoring mechanism, and also supports expansion through the mechanism of filter. Druid has a StatFilter for slow sql recording, but I found some shortcomings in using it: The print log of this Fi ...

Posted by jonsof on Mon, 29 Jun 2020 04:13:38 +0200

RocketMQ dead letter queue | how to deal with the exception of the consumer?

stay RocketMQ repeated consumption problem | the introduction of idempotent mechanism into the core process of order system In this paper, we discuss the problem of repeated message consumption. A better solution is to use business judgment on the consumption side to ensure the idempotence of the interface, so as to avoid the problem of repeate ...

Posted by GaryE on Sat, 27 Jun 2020 10:41:09 +0200

Android studio novice development: weather app (Baidu map api + wind weather api + city query + broken line display)

Android studio novice development: weather app (Baidu map api + wind weather api + city query + broken line display) 1. Content introduction 2. Environment configuration 3. Import another demo 4. AS project analysis 5. Weather project flow 6. Data exploration 7. Module architecture 8,sharedpreference 9. C ...

Posted by jej1216 on Sat, 27 Jun 2020 10:24:04 +0200

Task 3 Mysql multi table & foreign key & database design

1 multi meter 1.1 multi table description In actual development, a project usually needs many tables to complete For example, the database of a shopping mall project needs many tables: user table, classification table, commodity table, order table 1.2 disadvantages of single table 1.2.1 table building C ...

Posted by powaz on Sat, 27 Jun 2020 10:16:57 +0200