Demystifying Oracle Data Block – 1

Oracle consists of various logical and physical structures, namely :

  1. Oracle Datablock
  2. Extents
  3. Segments
  4. Tablespace
  5. Datafiles

At the finest level of granularity, Oracle stores data in data blocks (also called logical blocks, Oracle blocks, or pages). One data block corresponds to a specific number of bytes of physical database space on disk. You set the data block size for every Oracle database when you create the database. This data block size should be a multiple
of the operating system’s block size within the maximum limit. Oracle data blocks are the smallest units of storage that Oracle can use or allocate.

Oracle manages the storage space in the datafiles of a database in units called data blocks. A data block is the smallest unit of data used by a database. In contrast, at the physical, operating system level, all data is stored in bytes. Each operating system has a block size. Oracle requests data in multiples of Oracle data blocks, not operating system blocks. Continue reading

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De-mystifying the Oracle Data Block – 2

Oracle consists of various logical and physical structures, namely :

  1. Oracle Datablock
  2. Extents
  3. Segments
  4. Tablespace
  5. Datafiles

At the finest level of granularity, Oracle stores data in data blocks (also called logical blocks, Oracle blocks, or pages). One data block corresponds to a specific number of bytes of physical database space on disk. You set the data block size for every Oracle database when you create the database. This data block size should be a multiple
of the operating system’s block size within the maximum limit. Oracle data blocks are the smallest units of storage that Oracle can use or allocate.
Know more about Oracle Datablock.
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Booting Process of Linux

Being a DBA requires one to be comfortable working on Linux/Unix.

So I thought of writing a post on the booting process of Linux, well this is the first step towards understanding Linux.

This information/knowledge might be known to many before-hand. But trust me this is the most important step in knowing the Linux/Unix.

So let’s get started with the booting process.

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Introduction to DBMS and RDBMS

Flat Files – Advantages and Disadvantages.

A flat file is an archive of data that does not contain associations with various records or is a non-social database. A better than average instance of a level record is lone substance simply archive that contains each one of the data required for a program that is frequently secluded by some kind of delimiter. A level database is fundamentally less requesting to understand and setup than a customary database, however, may need for any program that is a great part of the time used or contains countless. Continue reading

What exactly happens when you fire a query?

This is for them the people who are needing to start as an Oracle DBA. If they have to make a sensible picture of Oracle Architecture by then, in particular, they need to perceive what is SQL query lifecycle in Oracle. So lets deep dive and try to figure out how exactly a query works.

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Oracle Database Re-Organisation.

The idea is that we find out all tablespaces in which schema’s data is present, then we drop schema plus its related tablespace and recreate them, in the end, take an import which reduces fragmentation in the database, thereby improving performance.
After the Re-org Activity, the database performance increases and size reduces.
Below are the commands for Re-org Activity :
Schema considered for performing the Re-org is NEFT.
Defer the Dataguard


Taking an Export Backup

 C:\> expdp dumpfile=dumpfile_name.dmp logfile=logfile_name.log schemas=NEFT


 SQL> spool 'C:\ReOrg.txt'
 SQL> set pagesize 200

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