Joords Oracle DBA blog

When upgrading an application or implementing improvements on stored PL/SQL procedures rule is compiling of those objects needed. During this phase, the end users can not using the application, they must wait until the whole change in the application implemented is finished or otherwise unexpected behavior may occur. In Oracle 11g Release 2 this problem is solved by usubg editions. With editions it is now possible to do live deployments of the new code to compile, whitehout users have to wait for implementing the changes. This is the end of a 'BIG BANG' at application upgrades. It is even possible to have multiple application versions operational. In this blog i will descibe the mechanism of the Edition Based Redefinition .

The (IP=FIRST) statement will make the listener create a listening endpoint on the IP address to which the given HOST resolves. By default, without (IP=FIRST), the listener will listen on all network interfaces (e.g. INADDR_ANY) .

Architecture, of the Shared Server Database Configuration The best position to be in will always be based on understanding. The components of the Shared Server database configuration consist of the Dispatchers and the Shared Servers. These components run as separate processes in the operating system (or threads in some operating systems). They interact with each other through the use of a Common Queue (CQ - also known as the Virtual Queue) and individual Dispatcher Queues. Both queues reside in the Shared Global Area (SGA) and are sized automatically by the database itself. Another component of Shared Server is not a process but an abstraction of the user session(more of an owned pointer), called a Virtual Circuit (VC). The communication between the Dispatchers and Shared Servers is primarily done by passing ownership of a Virtual Circuit from one to another.

Static service name is an  important part in the failover and snapshot mechanisme by the Standby database for using as a HA and test enviroment. Oracle Net Service uses the TNSNAME to resolve the path to the database and initiates a connection to the listener at the target system using the service name in the TNSNAME entry. Command to change the snapshot database to physical standby database: DGMRL> CONVERT DATABASE "JOORDS_DR0" TO PHYSICAL STANDBY; During these operations the the snapshot database needs a restart of the database. When the database is down, the service that is specified by TNSNAME is not registerd so an Oracle Net Service connection cannot be made to the database.Result is a failed operation of the convert database to physical standby. Monitoring the listener.log will give you the information of the error. and what the request is ORA-12514: listener does not currently know of the service request in the connect descriptor

In Oracle 11g Oracle Application Express (APEX) is now a standard component in the Oracle 11g RDBMS. The APEX component is intergration with the Oracle Database and ensures that the application builts with Oracle APEX benefit from the reliability, security, scalability and availability offered by the Oracle database. Oracle Real Application Cluster (RAC) is recommended for applications that require High Availability (HA), scalability, and workload management. How can we intergrate the High Availability (HA), scalability, and workload management functionality to the APEX module in a RAC environment In this blog I descibe, how to use and configure APEX module in a RAC database environment. In a normal High Availability for database enviroment is the Oracle HTTP server an unprotected feature by the Oracle Clusterware.

Oracle has introduced LOBs for managing large unstructured data insite the Oracle database. The introduction of LOBS suffers from several drawbacks in Oracle version before Oracle 11g: The LOBs where created for mostly " write once, read many times" operations and couldn't handle frequent updates LOBs assumed low concurrent usage data Undo retianed by setting the retention and pctversion parameters, addidition management burden LOBs weren't expected to be very large in size LOBs size is uniform, max chunk size could only be 32KB LOBs were not planned with concurrent usage requirements in Oracle RAC in mind The reality has changed en today LOBs are quite large, and comes in all sizes. Oracle 11g introduced a complete new way of handeling unstructured data to address the concerns resulting from the way LOBs are currently implemented. The new introduced LOB data type is called : Oracle Securefiles. The old LOB data type wil be referenced by Oracle as BasicFil...

Oracle 11gR2 ASM supports a new type of file called a “volume file” which may be created in its own DISK GROUP or which may share space in another disk group. Volume files are externalised to the Unix operating system by the oracleadvm device driver and appear dynamically as special files in the /dev/asm directory.