Database Administrator

Diagnosis and repair of a rac vip drift Background The customer's 10 Gb database VIP is down, causing VIP load to another node Event support details 04:29:56. went OFFLINE unexpectedly occurs in the VIP of machine 1 of 378. Check the cause of VIP

Application of Oracle timer and Oracle Timer Oracle timer. Once set, the restart of the server will not affect the execution of the Oracle timer (scheduled to be executed every day ), Begin sys. dbms_job.submit (job =>: job, what => 'check _ err; ',

How to view the physical file storage location of the MySql database I want to export the database file in mysql, but I cannot find it. I say there is a path in the configuration file on the Internet, but I open my configuration file and all the

Use the Oracle dbms_random function to quickly generate multiple test data entries. Database development or management personnel often need to create a large amount of test data, and tens of thousands of data records are required. If one data entry

Data structure, data structure and AlgorithmDynamic search When a query table is stored in an ordered Storage Structure and needs to be ordered, if you insert, delete, or sort a query table, you must move a large number of records. When there are

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 | + ---- + -----

Query the method for binding variable values in Oracle SQL statements, oraclesql Alter session set nls_date_format = 'yyyy-mm-dd, hh24: mi: ss'; set linesize 400col SQL _Id format a20col name format a20col datatype_string format a14col value_string

Rising Temperature, risingtemperature Given a Weather table, write a SQL query to find all dates Ids with higher temperature compared to its previous (yesterday's) dates. + --------- + ------------ + ---------------- + | Id (INT) | Date (DATE) |

Mysql Study Notes 6 (Data Definition Language DDL), learning notes ddlThe SQL language includes four main programming languages: Data Definition Language (DDL), data operation language (DML), and data control language (DCL) there is also a

With rollup and MySQLWITHROLLUP in MySQL MySQL's extended SQL has a very interesting application WITH ROLLUP. The same statistics (SUM, AVG, COUNT…) are performed based on the grouping statistics ...), Similar to the statistical functions in Oracle,

Solve the problem that mysql service cannot be started and Mysql is reinstalled in the last step. mysql step Mysql services are often the most troublesome and often need to be reinstalled. Many people cannot unload the residual files and cannot

Database set Query Database collection operations mainly include three aspects: 1. Union merge rows Union is used to merge two query results and deduplicate the same row while merging. For example: If we need to display all the union sets

MHA clears relay log (purge_relay_logs) and relaylogpurge By default, the slave database's relay logs in the MySQL database will be automatically deleted after the SQL thread is executed. However, in the MHA scenario, the recovery of some lagging

Remotely and quickly kill a session !, Remotely kill a session!Today, A developer called A (not to mention the information) asked in the group:The table is stuck when a large amount of data is inserted. I found that the table is locked and the

Mysql architecture arrangement, mysql Architecture MySQL is composed of data files and database instances. It is a single-process, multi-thread architecture.Database Files: a collection of physical operating system files or other files. In mysql,

Oracle modifies the column type. oracle modifies the column type.1. If the field data is empty, you can directly execute the following command regardless of the field type:Alter table tb modify (name nvarchar2 (20 ));2. If the field has data, you

Locale: facet: _ S_create_c_locale name not valid solution, isnotavaliddate Among many shell scripts, we often see the previous sentence "LC_ALL = C" SAR_CMD = "LC_ALL = C sar-u-B 1 5 | grep-I average" in front of a command. meaning? LC_ALL = C is

Mysql 5.6 and mysql5.6Limits in MySQL 5.6Sql Join restrictions:  Database and table quantity limit: The table size of a Mysql database is generally determined by the size limit of a single file in the operating system, not by the mysql kernel; File

SQLite tutorial (8): command line tool introduction, sqlite command line To do well, you must first sharpen your tools. Learning SQLite's command line tool is very helpful for us to learn SQLite itself. The most basic one is that it makes learning

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