Data Concurrency A requirement of a multiuser RDBMS is the control of data concurrency, which is the simultaneous access of the same data by multiple users. Without concurrency controls, users could change data improperly, compromising data integrity. For example, one user could update a row while a different user simultaneously updates it. If multiple users … Read more
12.2 Index Advanced Compression “High” Let’s begin by creating a table and explicitly creating a NOCOMPRESS index in the WHALE tablespace: SQL> create table WHALE (id number, Slno number, name varchar2(38));Table created. SQL> insert into WHALE select rownum, mod(rownum,10), ‘BLUE WHALE’ from dual connect by level <= 1000000;1000000 rows created. SQL> commit;Commit complete. SQL> create … Read more
The specific methods for creating a database are: With Database Configuration Assistant (DBCA), a graphical tool. With the CREATE DATABASE SQL statement. 1. Specify an Instance Identifier (SID) The ORACLE_SID environment variable is used to distinguish this instance from other Oracle Database instances on the same host computer. 2. Ensure That the Required Environment Variables Are Set 3. Choose a Database … Read more
Normally if you are trying to shrink a compressed table lets say you get below error, and the trick to solve it is below :- For partition tables and for normal tables There are two possibilities:1: The SHRINK clause is not valid on a compressed table and you will get ORA-10635 . (b) Autosegment space … Read more
Space allocation in the UNDO tablespace is unique and does not follow the same rules as normal tablespaces. Data within the tablespace frequently grows and shrinks throughout the life of the instance. There are three categories of blocks in the UNDO tablespace: Active, unexpired and expired Active: Blocks that contain active UNDO data for active … Read more
SYSTEM Tablespace is Growing Abnormally in 12c My SYSTEM tablespace was growing rapidly. This was happening in my test environment. We observe that we were not doing much on this database. Only few users were working to test the application and doing approx 40-50 transaction per day. That’s it.There was no much load as well, … Read more
A transaction is a logical, atomic unit of work that contains one or more SQL statements. A transaction groups SQL statements so that they are either all committed, which means they are applied to the database, or all rolled back, which means they are undone from the database. Oracle Database assigns every transaction a unique … Read more
Cluster Verification Utility (CVU) … Oracle Enterprise Manager … SQL*Plus … Server Control (SRVCTL) … Database Configuration Assistant … Fleet Patching and Provisioning … Cluster Verification Utility (CVU): CVU is a command-line tool that you can use to verify a range of cluster and Oracle RAC components, such as shared storage devices, networking configurations, system … Read more
Adding Disks to a Disk Group is done with the “alter diskgroup” command.Oracle provides the alter diskgroup command to adding or removing physical disks within SQL*Plus: First we identify the ASM diskgroup where we want to add the disk: Next, we identify the disks to see which disk should be added to the diskgroup: IF … Read more
A database link (DBlink) is a definition of how to establish a connection from one Oracle database to another. Type of Database Links: Private database link – belongs to a specific schema of a database. Only the owner of a private database link can use it. Public database link – all users in the database … Read more