About of Database Systems and Information Technologies
Oracle Data Guard ensures high availability, data protection, and disaster recovery for enterprise data. Oracle Data Guard provides a comprehensive set of services that create, maintain, manage, and monitor one or more standby databases to enable production Oracle databases to survive disasters and data corruptions. Oracle Data Guard maintains these standby databases as copies of…
I installed Oracle 12c Data Guard, everything was okey. But, I got an error like below when I wanted to connect data guard database with Toad or SQL Developer. tnsping was okey. Error SQL Developer : Status : Failure -Test failed: IO Error: Got minus one from a read call Listener.log 10-OCT-2017 15:01:16 * (CONNECT_DATA=(CID=(PROGRAM=SQL…
PostgreSQL has few feature for standby technology. I generally use streaming replication. This is very easy and confident. Streaming replication use a replication user for replication operations.Streaming replication allows a standby server to stay more up-to-date than is possible with file-based log shipping. The standby connects to the primary, which streams WAL records to the…
Oracle Real Application Clusters (Oracle RAC) is a clustered database infrastructure of Oracle Database based on a comprehensive high-availability stack that can be used as the foundation of a database cloud system as well as a shared infrastructure, ensuring high availability, scalability, and agility for any application. Oracle Real Application Cluster has been using with…
PostgreSQL 10 has very good new features. In my opinion, mainly new features are Logical Replication, Improved Parallel Query, Scram Authentication, Declarative Partitioning. Logical Replication : PostgreSQL has had physical replication that often called streaming replication since version 9.0, but this requires replicating the entire database, cannot tolerate writes in any form on the standby…
Sometimes, you may need to change redo log size to perform optimum size for performance. If you want to change redo log size of both standby side and primary side, you can use below commands. Current Status Of Redo Logs Primary Side SQL> select group#,sum(bytes/1024/1024)”Size in MB” from v$log group by group#; GROUP# Size in…
You can use flashback technology on standby side. If you want to make application test on database, you can use data guard as read write mode temporarily with flashback technology. You can create a restore point on standby side then you can do any transaction on standby side to test or any other purpose. After…
You can use the same steps to switchover for single data guard or multiple data guard configuration. Switchover operation will convert primary side to data guard and data guard to primary side. You have to control listeners whether it is running before switchover steps. Switchover Steps Primary Side SQL> alter system archive log current; SQL>…
Oracle 11g R2 database supports multi standby database structure up to 30 standby databases. We can use remote destinations for real time apply standby structures with todays network technologies. If your remote destination network is not good, you can use archivelog apply for remote destination with some delay. System informations are like below. System Informations…
Oracle 11g R2 database supports cascade standby database structure. If you are using RAC on primary side, your database version has to be least 11.2.0.2 to support cascade standby structure. You can use to reduce the load on your primary database with using cascade standby database structure. Primary database redo is written to the standby…