I'm reading the "Expert Oracle Database Architecture" book of Thomas Kyte, which is a must read for everyone who is serious on being an Oracle DBA.

Jonathan Lewis already said: "Frankly, if every DBA and developer in the world were made to work carefully through Tom Kyte’s book, I’d probably have to start offering consultancy services to SQL Server users because the number of clients needing Oracle consultancy would drop dramatically." in the foreword of the book. Still, i wanted to share some paragraphs from the "Data Files" part of the book. Following are taken out of only three pages of the book. I'm sharing this to show how the book is full of information and encourage you to immediately buy one and read.

Segments
==============================
You will find many CREATE statements that create multisegment objects. The confusion lies in the fact that a single CREATE statement may ultimately create objects that consist of zero, one, or more segments! For example, CREATE TABLE T ( x int primary key, y clob ) will create four segments: one for the TABLE T, one for the index that will be created in support of the primary key, and two for the CLOB (one segment for the CLOB is the LOB index and the other segment is the LOB data itself). On the other hand, CREATE TABLE T ( x int, y date ) cluster MY_CLUSTER will create zero segments (the cluster is the segment in this case).

Extents
==============================
Extents vary in size from one Oracle data block to 2GB. 11g Release 2 has introduced the concept of a “deferred” segment—a segment that will not immediately allocate an extent-, so in that release and going forward, a segment might defer allocating its initial extent until data is inserted into it.

Blocks
==============================
Here’s a little-known fact: the default block size for a database does not have to be a power of two. Powers of two are just a commonly used convention. You can, in fact, create a database with a 5KB, 7KB, or nKB block size, where n is between 2KB and 32KB.

Most blocks, regardless of their size, have the same general format, which looks something like:

 ------------------
|Header           | -> type of block (table block, index block, and so on), 
|                  |   transaction information when relevant regarding active and 
|                 |   past transactions on the block; and the address (location) 
|                 |   of the block on the disk.
|------------------|   The next two block components are found on the HEAP-                 |                  |   organized tables.      
|Table Directory   | -> The table directory, if present, contains information  
|                 |   about the tables that store rows in this block
|------------------|
|Row Directory     | -> The row directory contains information describing the 
|                 |   rows that are to be found on the block.
|------------------|
|                  | -> The remaining 2 pieces of the block are straightforward
|Free Space        |   there may be free space on a block, and
|                  |   then there will generally be used space that is 
|                  |   currently storing data.
|------------------|
|                  |
|Data              |
|                  |
|------------------|
|Tail              |
 ------------------


Exceptions to this format include LOB segment blocks and hybrid columnar compressed blocks in Exadata storage, for example, but the vast majority of blocks in your database will resemble the format in Figure

33 Responses so far.

  1. Maa-IT says:

    It is very good blog.I am also looking for this from a long time.Many people like to visit here.I have seen many things over here.It is very good.

    Real Application Cluster

  2. Anonymous says:

    thanks for share..

  3. v saranya says:

    Thanks for sharing a information its really helpful for me to understand

  4. Path Infotech is in the field of oracle training program from past several years.

    For more info : Oracle Certification Program

  5. i really appreciate knowledgeable post. thanks

  6. Likitha says:

    Yes, you are absolutely correct...And it is very informative and very clear and easy to understand.. seo training in chennai

  7. valuable information..

    Hadoop training in hyderabad.All the basic and get the full knowledge of hadoop.
    hadoop training in hyderabad



  8. Thanks For Sharing.It is very useful information

    Starpmo is one of the best institute to provide Online training courses in hyderabad. We have real time industry experts to provide Online classroom training


    pmp training in hyderabad


    pmp training

    Pmp Online Training In Hyderabad

    PMP Exams Hyderabad

    For more details Visit Us:Starpmo.com

    Contact Us:+91 7095608254

  9. This comment has been removed by the author.
  10. Sravani says:

    Thank you for sharing such a nice and interesting blog with us. I have seen that all will say the same thing repeatedly. But in your blog, I had a chance to get some useful and unique information.

    Oracle Fusion HCM Online Training

  11. raju says:

    Thank you for sharing such a nice and interesting blog.
    Oracle Fusion Financials Online Training

  12. Oracle says:

    I would like to thank you for the efforts you have made in writing this article. I am hoping the same best work from you in the future as well.

    Oracle Fusion SCM Online Training

  13. Naga says:

    Very interesting blog, keep posting such an informative post.

    Oracle Fusion Financials Online Training

  14. leela says:

    Really very helpful article, Thank you for sharing interesting blogs.

    Oracle Fusion Technical Online Training

  15. Bairavi says:

    Thanks for sharing this informative blog. If anyone wants to get seo training in chennai | digital marketing training in chennai , Please visit DLK CDC located at Chennai.

  16. This comment has been removed by the author.
  17. Really excellent information and thank you for giving your valuable information

    oracle fusion financials online training

  18. Hey Really Thanks for sharing the best information regarding oracle,hope you will write more great blogs.

    Oracle Fusion SCM Online Training

  19. Vijaya says:

    I feel really happy to have seen your webpage and look forward to so many more entertaining times reading here. Thanks once more for all the details.

    Silver Light Training in Chennai | Java Spring Training in Chennai.

  20. unknown says:

    Informative Blog. Thank you for sharing
    aws training in chennai



  21. Nice blog..! I really loved reading through this article. Thanks for sharing such a amazing post with us and keep blogging...


    Best Data Science online training in Hyderabad

    Data Science training in Hyderabad

    Data Science online training in Hyderabad


  22. You truly did more than visitors’ expectations. Thank you for rendering these helpful, trusted, edifying and also cool thoughts on the topic to Kate.
    fire and safety course in chennai

  23. Anonymous says:

    pmp training bangalore,Prepare for PMP Certification Exam and earn 35 Contact Hours. Master 10 Knowledge Areas and 47 Project Management Processes based on PMBOK Guide
    pmp training in bangalore

Powered by Blogger.

Page Views

- Copyright © Emre Baransel - Oracle Blog -Metrominimalist- Powered by Blogger - Designed by Johanes Djogan -