Sep 27 2020
Result set rows can be fetched either a row at a time or in groups.
In the fetch stage, the database selects rows and, if requested by the query, orders the rows. Each successive fetch retrieves another row of the result until the last row has been fetched.
Continue readingSep 26 2020
This topic will describe how Oracle works internally with Index and Full Table Scan.
Sep 19 2020
Dynamic Performance (V$) Views: The Oracle Server contains a set of underlying views that are maintained by the server and accessible to the database administrator user SYS. These views are called dynamic performance views because they are continuously updated while a database is open and in use, and their contents relate primarily to performance.
Data Dictionary View: Data dictionary tables are not directly accessible, but you can access information in them through data dictionary views. To list the data dictionary views available to you, query the view DICTIONARY.
Sep 19 2020
In this topic, I will demonstrate Oracle RAC components.
Sep 18 2020
In topic, I will descript how Oracle handle once we revoke tablespace quota from user. Once blocks assigned to a segment, even after revoked the Tablespace quota and deleted records from table, all allocated block will remain mapping with segment until we released block by using Shrink.
This is the one good reason to release the space once we delete lots of records from a segment.
Sep 02 2020
Sometimes DBA got request to drop the table’s columns. Oracle has following options to complete this task.
In this article, I will discuss which option is more appropriate for big size of table. For small table, even physical delete will not take take much time or resource.
Continue readingSep 01 2020
Until Oracle 8i released, Oracle Introduced Parallel Server on Oracle 6i version. Oracle Introduced Real Application Cluster concept on Oracle 8i version. Oracle Cache Fusion is one of the important component in Oracle RAC environment.
What is Cache Fusion:
Oracle RAC has two or more instances, and it uses Cache Fusion to smoothly move data blocks between these instances’ buffers across the cluster connection. If one instance reads a data block from the disk and another instance needs the same block, it’s faster to grab it from the instance that already has it in its memory (SGA) than reading from the disk again. This quick transfer across the network is way faster than dealing with the slower disk operations, making Oracle RAC work better.
Continue readingAug 30 2020
I will describe the installation process of Oracle 19c (19.3) Database on Oracle Linux 7.1 on VM.
Aug 24 2020
Sometime you may need to change the Network Interface Name on your system. I faced issue while I was cloning a node to prepare a new node for RAC Environments on Oracle Linux 6.5.
When you clone a VM, you need to reassign the Network device means it will assign new UUID for the device and it will create new Network Interface at OS level. But For RAC, You need to set same name of Network Interface for all nodes. I got below error while was trying install GI (Grid Infrastructure) with different Network Interface Name.
Continue readingAug 18 2020
If create a database using DBCA, usually password file create on ASM Diskgroup. For RAC, this is also recommended to use ASM Diskgroup for spfile and password file. In this topic, I will show how to copy password file from ASM of Primary database to Standby on ASM.
Password File location on Primary Database:
[oracle@ocmnode1 ~]$ . oraenv ORACLE_SID = [ORCL1] ? +ASM1 [oracle@ocmnode1 ~]$ asmcmd pwget --dbuniquename ORCL +DATA/ORCL/PASSWORD/pwdorcl.256.1048094823Continue reading
