Database Administrator

MySQL compilation and installation and compilation ParametersAdd a mysql group and a mysql user [Root @ CentOS mysql] # groupadd mysql[Root @ centos mysql] # useradd-g mysql Compilation and Installation Tar-zxvf mysql-5.1.35.tar.gz./Configure/--

User-managed backup refers to the use of OS commands to back up physical database files. Back up databaseDatabase Consistency backup: After the database is closed, the physical files of the database are backed up. At this time, the scn values of the

1.Dynamically create auto-increment Sequences: DeclareV_ SQL varchar2 (1000 );V_num number (20): = 1;BeginV_ SQL: = 'create sequence sqbs ';Select max (sqb. id) + 1 into v_num from sqb;If v_num is null then v_num: = 1;V_ SQL: = v_ SQL | 'maxvalue 999

1. install MySQL database first download MySQL from the MySQL official website, and then enter the directory of the downloaded Installation File, run the following command to install, where the MySQL-server-community-5.1.56-1.rhel5.i386.rpm is just

Notes for configuring data-source in the struts-config.xml:Name: data-sourceDescription: The data-source element defines specific data source attributes:@ Key: when multiple data sources need to be configured, it is equivalent to the data source

Test code: DECLARE TYPE list_of_names_t is table of VARCHAR2 (100) index by PLS_INTEGER; Happyfamily list_of_names_t; Rochelle row PLS_INTEGER; BEGIN -- Build table data which indexIsNot consecutive. Happyfamily (2020202020): ='Lil'; Fig (-1

Card refers to the number of rows processed in this step in the plan; cost refers to the resources consumed by this step in cbo, and this value is relative value; bytes refers to the number of bytes of all records processed in this step in cbo. It

MTBF: Mean-Time-Between-Failures average Time Between two FailuresMTTR: Mean-Time-To-Recover average fault recovery Time Fault Type:1. faults caused by SQL expressionsBUG, invalid data, permission exceeded, quota limit2. User process

Restore: restore recover recoveryFirst use the restore database command to restore to the backup point through the backup file, and then use the recover database command to restore to the time point when the media is damaged through the archive log

1. master database check and settings Assume that the new service is named ORCL_TAF.LK. SQL> exec dbms_service.create_service (service_name => 'orcl _ TAF. LK ', network_name => 'orcl _ TAF. LK ');SQL> exec dbms_service.start_service (service_name =>

When configuring the data guard network listener, the connection test reports the following error: ERROR:ORA-12514: TNS: listener does not currently know of service requested in connectDescriptor The error is caused by a new db_unique_name = 10 upli

RMAN> startup nomount; RMAN> SQL 'alter session set nls_date_format = ''yyyy-mm-dd hh24: mi: s ''";-- Because rman reads the time format using environment variables by default, which is different from the fixed format of sqlplus, you must set the

What to do before the transaction is committed Before submitting a transaction, Oracle must do the following: ① Remember what the data looks like before it is modified ② Remember what data will be changed soon ③ Remember the association between

1. Find the most resource-consuming SQL We can first use top and other tools to find the process with the best resources (remember the process number), for example, the operating system process number is 2796, And then according to this process

1. Create a crontab for an Oracle userSu-root Crontab-u oracle-l*/5 */home/oracle/oracle_backup.sh(This shell file is executed every five minutes. This is a convenient test. You can modify the time for the test .) 2. Create a shell

The memory structure is one of the most important components of the Oracle service system and a key element that determines the overall performance of the Oracle server. During the running process of the Oracle server, the SGA size directly affects

In Oracle 10 Gb, if we did not select an installation example when creating an instance, we can also create it using the script under $ ORACLE_HOME/demo/schema after creating the instance. For details about the creation method, the official

Today, the VM memory is reduced a little, and the following error occurs when the data is started: SQL> startup ORA-00845: MEMORY_TARGET not supported on this system I guess it should be the problem of system memory conflicts with sga. Then I

When the database instance is too large, the Oracle_SID displayed every time the export is not frequently used. It would be nice to make the default customization. Now I will explain how to define it in the Linux environment: 1. su-oracle 2.

Automatic Workload Repository (AWR) collects, processes, and maintains performance system information, providing powerful help for performance tuning problem detection. Statistics collected and processed by AWR include: 1. segment statistics; 2.