Database Administrator

Open resetlogs startup reports ORA-00392 ORA-00312 Error Error message: SQL> alter database open resetlogs; Alter database open resetlogs*ERROR at line 1:ORA-00392: log 3 of thread 1 is being cleared, operation not allowedORA-00312: online log 3

Redis memory fragments Redis uses jemalloc to allocate memory by default. According to the best article in fast '14, when a variable-length key-value load occurs, the fragmentation problem may occur: low memory utilization, the actually allocated

ERROR 1129 is reported during MySQL connection. Problem description: ERROR 1129 is reported when the mysql command is used to connect to the mysql database; ERROR Description: ERROR 1129 (HY000): Host 'mysql02' is blocked because of unknown

Mysql auto-increment ID start value modification method, mysql modification methodMany friends in mysql think that the field AUTO_INCREMENT Type Auto-increment ID value cannot be modified. In fact, this is an incorrect understanding. The following

PL-SQL trigger, pl-SQL triggerZookeeper PL-SQL trigger Triggers are a technology provided by many relational database systems. In the ORACLE system, triggers and similar procedures and functions have PL/SQL blocks that declare, execute, and handle

A large number of diagnostic processes are generated using redo logs.A large number of diagnostic processes generated by redo logs This article is an original article. For more information, see the source: Http://write.blog.csdn.net/postedit/41249705

For troubleshooting mybatis concurrency, refer to hibernate and mybatishibernate. A typical example is that two bank operators operate on the same account at the same time. For example, IF operator A and operator B read an account with A balance

Redis learning Manual (transaction), redis learning manual transaction I. Overview: Like many other databases, Redis also provides a transaction mechanism as a NoSQL database. In Redis, the four commands MULTI/EXEC/DISCARD/WATCH are the cornerstone

ORA-27154 cannot start database due to semaphore problem, ora-27154 Database Prompt (11.2.0.1) when the Test Library executes startup ): Error querying ORA-27154: Error: ORA-27154Text: post/wait create failed --------------------------

Step-by-step explanation of ORACLE (Lecture 2), lecture 2 of oracle1. Common ORACLE Data Types (not commonly used for other types) (1) character type 1. char fixed length, up to 2000 characters. For example, put the first four characters of char (10)

Import and export without landing dataIn this case, the local disk space is insufficient, but some data needs to be migrated. We met such a situation yesterday: A friend needs to import a GB log table from 10 GB Data to 11 GB, but he wants to export

Niuke news publishing system-Learning Web tips and summary, and news publishing system webJuly November 10, 2014 is an unforgettable day. On this day, the BS learning of xiaobian started, starting with BS. Starting from niuyun's news publishing

Mysql ifnull function, mysqlifnull Function The usage of the mysql ifnull function is described in detail below for your reference. If you have encountered similar problems in using the mysql ifnull function, take a look. Mysql ifnull (expr1,

Basic Database Table operations-create tables, indexes and queries, and database Indexes1. Define, delete, and modify basic tables(1) define basic tablesCreate table ( [column-level integrity constraints][, [column-level integrity constraints]...

Oracle data migration (from Oracle11G to Oracle10G) and oracle11goracle10g1. Database statusThe production environment is 11 GB, the linux system, and the testing environment is 10 Gb. For windows systems, you need to export all the data of a user

Use Cases of Oracle update + with, oracleupdateDrop table test purge;Create table test (Id number,Code varchar (20 ),Name varchar (20));Insert into test values (1, '20170101', 'aaa ');Insert into test values (2, '20170101', 'bbb ');Insert into test

An error occurred while starting Mysql Data migration. mysql migration I don't know why after work today, mysql has never been able to start. After a long time, I decided to reinstall it. My local server uses wamp. During the reinstallation, data

SQL % rowcount: Number of affected rows returned; SQL % rowcount: number of rows returned In oracle, the number of affected rows returned is: If SQL % rowcount Example: Update ut_calenderStatus t set t. calenderstatus = pi_flg, t. m = pi_M, t.

Use of cursors Define a cursor: Cursor calenderStatus_cur is select * from ut_calenderStatus; vr_calenderStatus ut_calenderStatus % rowtype; Open the cursor and extract the data from the cursor to the cursor row: Open events; loop

SQL EXISTS usage and SQLEXISTS usageFor example, a query in the Northwind database isSELECT c. CustomerId, CompanyName FROM Customers cWhere exists (SELECT OrderID FROM Orders o WHERE o. CustomerID = c. CustomerID)EXISTS is used to check whether a