Modern Oracle DBA

Database startup Normally database startup and shutdown required sysdba privileges. Database can be started using the below steps Start SQL Plus without connecting to the database Sqlplus /nolog Connect to Oracle Database as SYSDBA: sqlplus / as sysdba SQL> startup Database startup is staring up the instance including various modes Nomunt the database Mount the database Open the database Nomount Stage: Nomount stage instance will be start It will be read the all oracle parameter files like (spfile,pfile) It will start the memory(SGA) area and background process. Startup nomount stage mainly using for database creation,Cloning and DB recovery operations. Example: SQL>startup nomount SQL> startup nomount pfile='/<path>/init<SID>.ora'; Mount Stage: Mount stage is only allow for DBA activities does not allow the general access of database. It will be checks the controlfiles spe

Datapump is introduced in oracle database 10g(10.2.0.1) and later Oracle Data Pump technology enables very high-speed movement of data and  metadata from one database to another database. Oracle Data Pump is made up of three distinct parts The command-line clients, expdp and impdp The DBMS_DATAPUMP PL/SQL package (also known as the Data Pump API) The DBMS_METADATA PL/SQL package (also known as the Metadata API) Data Pump expdp and impdp using following Modes: Full Database Table User Tablespace EXPDP Full Database: Full database mode exports the all database objects. Table: Table mode export the specified table in user Example: Table definitions Table Data (all or selected rows) Table indexes User: User mode export the all objects from users schema Example: Table definitions Table Data Owner grants Owner indexes Tablesapce: Tablespace mode can be used to export the all tables in the speci

Why we need to increase the Java heap size: Mainly we need to increase the  EBS Performance. Default oacore JVM heap size is 512 MB it's supports 50 to 100 users When our R12.2 instance reach more than 200 users we need to be increase the oacore size for better performance. Oracle recommended to configure 2 GB JVM Heap Space for oacore. This can roughly support 150 to 200 users depending on usage. For higher user load additional oacore managed servers need to be created. Oracle recommend to have 1 managed server per 2 CPU. Following steps how  increase  the oacore size.  Step1: Login weblogic console Step 2: Click à lock and edit Step3: Choice the Domain tab and click à serves menu Step4: Click à oacore_server1 Step 5: Click à server start Step 6: Go to Argument tab Then change the xms and xmx values default value is 512m Default values -XX:PermSize=128m -XX:MaxPermSize=384m -X