Database Administrator

MySQL, DBI, and DBD must be installed for MySQL database development using perl in Linux. Apart from the good DBI installation, MySQL and DBD installation are not so smooth. The following describes how to solve the installation error: I. MySQL

Oracle backup features include: Advanced Replication) Streaming Replication) Slave uard) One worker uard: Dataguard is generally the first choice for dba in terms of high availability and Disaster Tolerance. After all, dataguard has an overwhelming

When MySQL5 source code is compiled, No curses/termcap library found is displayed, but the installation of curses termcap prompts that the library has been installed.The path can be added during compilation, that is./Configure-with-named-curses-libs

There are dual virtual tables similar to those in Oracle in mysql: the official statement is purely to satisfy select... from... mysql ignores the reference to this table. You can pay attention to the following: Select * from dual; mysql will

Table A records the following:AID aNum1 a200501112 a200501123 a200501134 a200501145 a20050115 Table B records the following:BID bName1 20060324012 20060324023 20060324034 20060324048 2006032408 The experiment is as follows:1. left joinThe SQL

The undo tablespace cannot be opened because it is damaged. When the undo tablespace file in the database is corrupted or the undo tablespace file is missing, the database cannot be opened. Both cases can be considered as one case, and the solution

Assume that no instance is created, no SCOTT user, and no EMP file are created when you create an Oracle database. Execute the following script files: Path: {ORACLE_HOME} \ RDBMS \ ADMIN 1. SQL> @ .. \ utlsampl. SQL (********)Used to create a SCOTT

During database O & M, it is inevitable that you need to query databases across multiple servers and multiple Oracle instances. For example, you need to check the value of the open_cursor parameter in all current production environment databases to

As we all know, undo is designed to ensure consistent read. That is to say, if you are not submitting the changed data, other sessions cannot view the changed content, if the other party reads the data, the data is still the previous data, and the

I. Paging query: 1. Minute by rowidSelect * from t_xiaoxi where rowid in (select rid from (select rownum rn, rid from (select rowid rid, cid from t_xiaoxi order by cid desc) where rownum 9980) order by cid desc;Execution time: 0.03 seconds 2. Score

10046 is a tool that anyone familiar with Oracle and SQL tuning is familiar. The 10046 and 10053 diagnostic events help us easily understand the behavior of the Oracle CBO optimizer and SQL Execution. In the case of commercial non-open-source Oracle,

During local DAO tests or unit tests, the db environment is sometimes difficult to implement, and even if the database environment is called, sometimes it does not want to add useless data to the db, spring provides a virtual db environment to

MySQL replication process: each time a write operation is executed, it stores a copy in its own database. At the same time, this write operation is also stored in a binary log file, and save them as events. Therefore, each write operation or

ORA-00257 archiving log error Solution In the actual project encountered a ORA-00257 error (insufficient space error), by looking for information, the vast majority of said this is due to archiving too many logs, occupying all the hard disk space

There is an automatic backup script program that asks rman. I have previously written an automatic backup case for the exp backup specific solution (Oracle automatic backup case on Linux platform (using exp tool )), now I want to add the rman

Flashback Query: queries the information of records stored in objects at a certain time point in the past, between the current time and a specified time point in the past. SQL> conn scott/OracleConnected.SQL> select

Implementation of almost hot standby MySQL based on LVM Almost Hot Standby: For mysql, if we want to create a snapshot using lvm, the innodb Transaction Log content may be written to the disk at the moment the snapshot is created, therefore, we must

Introduction to XtraBackup XtraBackup replaces the innodbbackup tool, and XtraBackup is fully compatible with the innodb Storage engine, and implements full physical layer hot backup for the innodb Storage engine. Site:

Suddenly I saw a saying on the Internet that the WHERE condition execution sequence of Oracle is from right to left. The reason is that when multiple 00904 characters in the WHERE condition of ORACLE are invalid, the error is returned in the order

Percona mysql 5.5.33 and mysql 5.6.14 performance test comparison: System: rhel 5.5,Test Tool: sysbench2-core CPU, hyper-threading, 4 logical CPUsInnodb_buffer_pool_size is set to 1 GB, and the number of connections is set to 1000.Test Time for each