Database Administrator

MHA online switching process In addition to automatic monitoring and switching, MySQL MHA provides online failover, which is mostly used for hardware upgrades and MySQL database migration. This mode provides fast switching and elegant blocking of

Oracle cursor use full solution This document covers almost all aspects of Oracle cursor use, all passed the test -- Declare the CURSOR; CURSOR cursor_name IS select_statement -- For Loop cursor-- (1) define a cursor-- (2) define the cursor

Oracle query fields by Field Type Sometimes we need to query specific field information in Oracle through the field name, field type, field length, field comment, table name. For example, my colleague asked me yesterday if blob type is used in our

Redis master-slave configuration and Sentinel Construction As one of the mainstream nosql database products, redis is widely used. This article describes the master-slave configuration method of redis and how to ensure high availability and

Two MHA switching exceptions (masterha_master_switch line 53) In the process of testing manual failover and online failover, MHA encountered two strange problems, and the test was not successful when calling the IP address, detected dead master xxx

Use Systemd to manage MySQL 7.1 compiled and installed on CentOS 5.6 CentOS 7.1 does not use MySQL 5.6 by default. The robust method is to compile and install the source code provided on the MySQL official website. However, the startup management of

Use flashback database to implement flexible data switching The customer has a requirement today, because the development has encountered some difficulties in the production environment, and the problem needs to be reproduced in the test production

Database and database LearningRelational Database The relational model proposed is E. f. codd (Edgar Frank Codd, 1923-2003). "Father of Relational Database" proposed the Relational Data Model E in 1970. f. codd, "A Relational Model of Data for Large

About Oracle Cluster Registry, oracleclusterAbout Oracle Cluster RegistryOracle Cluster Registry (OCR) is a file that contains information about the cluster node list and instance-to-node mapping information. OCR also contains information about

Customers Who Never Order, customersorder Suppose that a website contains two tables, the MERs table and the Orders table. write a SQL query to find all customers who never order anything. table: MERs. + ---- + ------- + | Id | Name | + ---- + -----

Oracle installation does not respond after clicking setup. oraclesetup Minimize the window opened on the desktop, and then you will see the prompt box for oracle Installation. If you do not see the prompt box, it may be that the installation

Configure HiveServer2 and 0.14.0hiveserver2 Based on version 0.14.0In the project, you need to access hive as a mondrian heterogeneous data source to execute MDX queries. Generally, when using hive, I directly execute SQL statements using hive

When installing ogg, run./ggsci to report an error./ggsci: error while loading shared libraries: libnnz10.so ......, loading 1. Virtual Server version: [oracle@localhost ~]$ cat /proc/version Linux version 2.6.32-300.10.1.el5uek (mockbuild@ca-build5

Oracle Memorandum 1, oracle Memorandum Database Administrator: Install and upgrade the Oracle database to create a database, tablespace, table, view, and index... Develop and implement backup and repair plans database permission management, tuning,

MongoDB BASICS (iv) Red Hat Enterprise 6.4x64 install MongDB 3.0 and configure mongodbmongdb Mongodb-org this package is a metadata package. The following four package packages are automatically installed during installation. Mongodb-org-server

SQL statement 1Use data Use mydata; Create a table Create table longmao ( Depeno int primary key, Dname varchar (20 ), Loc varchar (20) ); Insert data to the table Inseert into toroto values (1, 'feifei '); Show all tables Show tables; Show table

Mysql network disconnection and reconnection Recently, I was working on a project's background daemon program. I needed multiple threads to operate mysql database services. To enhance the robustness of daemon, I unplugged the network cable after

[Translated from mos] Why does GI Rebootless Fencing fail ?, Rebootlessfencing Why does GI Rebootless Fencing fail? Reference:Why Grid Infrastructure Rebootless Node Fencing Fails (Doc ID 1502282.1) Applicable:Oracle Server-Enterprise

Consecutive Numbers, consecutivenumbers Write a SQL query to find all numbers that appear at least three times consecutively. + ---- + ----- + | Id | Num | + ---- + ----- + | 1 | 1 | 2 | 1 | 3 | 1 | 4 | 2 | 5 | 1 | | 6 | 2 | 7 | 2 | + ---- + ----- +

Employees Earning More Than Their Managers, employeesearning The Employee table holds all employees including their managers. every employee has an Id, and there is also a column for the manager Id. + ---- + ------- + -------- + ----------- + | Id |