Mohammad Samad

Author's posts

Sep 27 2020

How Oracle Database Processes DML Internally

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. DML-Operation. Insert a Record into a Table. …

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Sep 26 2020

How Oracle Database Process Select Query Internally

This topic will describe how Oracle works internally with Index and Full Table Scan. Full Table Scan (No Index) when all blocks are available in Buffer Cache. Full Table Scan (No Index) when Blocks are not available in Buffer Cache. Select query Using index when get block from index and table segments. Select query Using …

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Sep 19 2020

V$ View & Data Dictionary View on Oracle

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: …

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Sep 19 2020

Oracle Real Application Cluster (RAC) Important Components

In this topic, I will demonstrate Oracle RAC components. SCAN IP VIP IP SCAN Listener Cache Fusion Cluster Interconnect RAC 2-way Global Cache Transfer RAC 3-way Global Cache Transfer Cache Coherency Global Cache Services (GCS) Global Resource Directory (GRD) Global Enqueue Services (GES)

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Sep 18 2020

After Revoked Tablespace Quota From User in Oracle

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 …

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Sep 02 2020

Unused or Drop Column? Which option should use?

Sometimes DBA got request to drop the table’s columns. Oracle has following options to complete this task. Logical Delete. Physical Delete. Claim space for logical delete columns. Claim space for Physical delete column. Conclusion. In this article, I will discuss which option is more appropriate for big size of table. For small table, even physical …

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Sep 01 2020

Oracle RAC Cache Fusion

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 …

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Aug 30 2020

Oracle Database 19c Installation On Oracle Linux 7.1

I will describe the installation process of Oracle 19c (19.3) Database on Oracle Linux 7.1 on VM. 1. Create VM. 2. Software Download. 3. Install Oracle Linux 7.1 on VM. 4. Oracle Database Installation Prerequisites. 5. Oracle Database Software Installation. 6. Create a Container Database Using DBCA. 7. Create a Non-container Database Using DBCA. 8. …

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Aug 24 2020

How to Rename Ethernet Interface to eth0 in Linux on VM

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 …

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Aug 18 2020

Copy Password File From Primary ASM to Standby ASM on Oracle 12c

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:

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