HugePages for Oracle

If you run a Oracle Database on a Linux Server with more than 16 GB physical memory and your System Global Area (SGA) is greater than 8 GB, you should configure HugePages. For large SGA sizes, HugePages can give substantial benefits in virtual memory management. Without HugePages, the memory of the SGA is divided into […]

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Fractured block in Oracle

A block in which the header and footer are not consistent at a given SCN. In a user-managed backup, an operating system utility can back up a datafile at the same time that DBWR is updating the file. It is possible for the operating system utility to read a block in a half-updated state, so that […]

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Monitoring changes to Oracle tables

I must thank my fellow DBA Franky Weber Faust for his publication in his blog. The main purpose of this type of monitoring, in my opinion, is to know the most altered tables, the amount of changes in these tables since the last collection of statistics. Why since the last collection of statistics? Because every time a […]

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Enabling Flashback Database in Oracle

Oracle Flashback Database, allows to quickly recover the entire database from logical data corruptions or user errors. It is very similar to PITR (Point In Time Recovery) which puts back the database to a state at a particular time in recent past. 1. Place your database in mount stage.

2. Set DB_FLASHBACK_RETENTION_TARGET to the requried […]

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ORA-15032: Not All Alterations Performed

While setting attribute on a ASM diskgroup, we got below error.

Solution: Alter operations on ASM diskgroups need to be done from sysman user , instead of sysdba user.

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Recreate Oracle Central Inventory

Inventory is the index for the oracle installation. All the details about the ORACLE_HOME including different utility versions, patch details etc. If you do a fresh Oracle installation the inventory will be updated. But if you copy the ORACLE binaries from some other location and if you are not updating the inventory, we cannot read […]

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Amount of redo generated during user-managed backup

I must thank my fellow DBA Franky Weber Faust for his publication in his blog. Introduction: –  In this article, we have a quick journey on redo log during user-managed backup. RMAN is the most recommended tool for performing backup and recovery of an Oracle database, but we know that this is not always the case and many […]

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Move tables (online / offline) in Oracle (9i-12cR2)

I must thank my fellow DBA Franky Weber Faust for his publication in his blog.  The goal here is to share the procedures for performing the move of tables in Oracle Database from version 9i to version 12cR2. Here in this article I am using 12cR2 (12.2.0.1) to also be able to demonstrate the features […]

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Oracle and it’s different Versions

Oracle Database Technology – the Oracle  server versioning  Oracle Version 2 – first commercial RDBMS Oracle Version 3 – rewritten in the  C programming language Oracle Version 4 – improved query performance Oracle Version 5 – added a networking stack for client-server computing Oracle Version 6 – OLTP improvements, Oracle parallel server Oracle Version 7 – first “Modern” Oracle New security model […]

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Index (B-tree)

B-tree Index B-tree stands for Balanced Tree in RDBMS. It is commonly used in database and filesystem.The B-tree enables the database to find a leaf node quickly. It is a good example of a data structure for external memory. Telephone directory, library are the best example of B-tree index.   Why do we use B-tree? keeps keys in […]

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