Database Administrator

Procedure:1. Write a StartOracle. SQL statement in the/directory.Vi/StartOracle. SQL Add the following two rows to saveStartupExit2. Configure/etc/rc. localAdd the following content to vi/etc/rc. local and saveSu-oracle-c '$ ORACLE_HOME/bin/lsnrctl

Download all file names:10201_database_linux32.zipFile size (KB ):653061KBModify the sysctl. conf file in the/etc/directory to add the kernel parameters. The key part is described as follows:Added content:Kernel. shmall = 2097152Kernel. shmmax = 2684

This article explains how to use grouping sets grouping in Oracle databases through the author's personal experience.When you use group by statements with Aggregate functions such as COUNT and SUM, you generally cannot get the total number of levels.

It is important to install MySql in a compressed package. In Windows, it is easy to decompress. Zip directly (Windows permission management is really weak -- | ). However, unzipping .tar.gz via coreora core7cannot be started. However, I started the

We have sorted out the most common Oracle commands for Oracle beginners to learn! 1,Create a tablespace:Create tablespace name datafile' file address and file name '[size] [autoextend [on | off]; Note: [size] indicates the size of the tablespace to

Oracle closes and enables archiving logs 1. Archive Mode 1 SQL> archive log list; # Check whether the archive mode is used2 SQL> alter system set log_archive_start = true scope = spfile; # enable active ArchivingSQL> alter system set

Error: ORA-12537: TNS: connection closed. Environment: Oracle: 11.2.0.2 OS: LINUX 5.6 Environment: RAC NODE1: 10.20.31.36 NODE2: 10.20.31.38   [Oracle @ ract1 ~] $ Sqlplussys/oracle@10.20.31.36: 1521/racdbas sysdba SQL * Plus: Release 11.2.0.2.0

Preparations for the operating system are omitted here:1. Create a respone FileDgdb-> cat db_install.rsp | grep-v ^ # | grep-v ^ $> db_install2013.rspDgdb-> more db_install2013.rspOracle. install. responseFileVersion

1. User Management 1.1 create a user (Database verification) Create user dave identified by pwd Default tablespace users Temporary tablespace temp QUOTA 5 m ON users;   1.2 modify a user Alter user dave quota 0 on system;   1.3 Delete a user Drop

1. Check alert logs Symptom description: During routine Oracle maintenance, you often need to check the alert alarm log to check whether the database is faulty. Cause analysis: Oracle 11g modified the log system, instead of using oracle9's alert

Operating system version: CentOS 5.8 64bit Database Version: 11.2.0.1 Problem description: Recently, the database was added to 32 GB of memory, and the MEMORY_MAX_SIZE parameter was increased to 28 GB, And the MEMORY_TARGET parameter was changed to 2

In Oracle, sequence is the so-called serial number, which is automatically increased every time it is obtained. It is generally used in places where the sequence numbers need to be sorted. 1. create sequenceFirst, you must have the create sequence

---------- Full backup -----------Backup set: block BACKUP used in data filesImage copy: a complete COPY of all data files.---------- Incremental Backup -----------A backup of a database that has changed since a specific time point. This time point

Version description Hadoop 1.0.3HBase 0.94.1Hive 0.9.0 Perform operations Hive> select count (*) from tablename; Exception prompt Exception in thread "Thread-54" java. lang. RuntimeException: Error while reading from task log url At

This error occurs when the insert statement is executed. Insert into Table 1 values (123,2423, 12 ); The structure of Table 1 has four columns. Obviously, only three columns are inserted, so this problem occurs. After the value of another column is

Starting from 9i, Oracle also provides a new Undo Data Management method, that is, using the Automatic Oracle Undo tablespace Management, usually abbreviated as AUM ). (1) check whether the empno = 7788 record exists in the Buffer Cache. If it does

For how to add and delete Voting Disks in Oracle RAC, refer: Oracle RAC backup and recovery Voting Disks The Voting Disks file does not need to be backed up every day. Generally, backup is required in the following situations: ①: After Clusterware

MySQL 5.6 brings us the memcached fof innodb api. The main advantage is that we can read and write the MEMCACHED plug-in through the most familiar SQL statements. I will not introduce installation and configuration. If necessary, visit the official

10.1 parallel recovery (v7.1) The goal of parallel recovery is to use parallel computing and I/O mechanisms to reduce the time for crash recovery, single instance recovery, and media recovery. When multiple data files on multiple disks are restored

Differences between Innodb foreign key and SQL standards: When there are many inserts, deletes, and updates rows in sel statement, fk will check one row. Innodb sets the shared row_level locks in the parent table or child table. MySQL CHECK