(Ep. 20) - Db2 REORG

The Db2 REORG is a fundamental command and a best practice for regular maintenance. On smaller tables, the process can be quick and painless, but what about large tables, or tables that require 24x7 access? Then things get a little tricky.
In this episode we will discuss why you would call a reorg, the different kinds of reorgs, benefits and drawbacks, syntax, and monitoring the process.
Timestamps:
00:58 - Why are REORGs needed?
01:28 - Repercussions of not doing a regular REORG
02:26 - Advantages/Disadvantages of Offline Reorg
03:47 - Phases of an Offline Reorg
05:51 - Advantage/Disadvantage of Online Reorg
07:53 - Phases of an Online Reorg
09:38 - Command Syntax
- Minor Syntax Correction:
REORG TABLE TABLENAME [PAUSE | STOP]
11:00 - Monitoring Reorg Progress
13:56 - Aborted Reorg Recovery
Useful Links:
(KC) Compare/Contrast Types of Reorg - tinyurl.com/yadaoeue
(KC) Phases of Offline Reorg - tinyurl.com/ya9o8jyc
(KC) Phases of Online Reorg - tinyurl.com/yanpxn6s
(Technote) Aborted Reorg Recovery - tinyurl.com/y9pr7gjc
(Blog) Best Practices for Reorg/Runstats - tinyurl.com/ycnbvf5z

[@Affflex]

Very clear explanation. Thank you!

[@sssdf816]

AWESOME !

[@i.f.7788]

Really good explanation! Thank you!

[@myunderstanding9904]

Awesome content... good explanation... recommended for professionals

[@kalpanamanoj8495]

Good Explanation .. Thank you very much ..

[@CHANDANDCMS]

Thank you So much .

[@hanurao8078]

Good info.Please clarify me at what phase we can interrupt online/offline reorg without impacting to table and db

[@MrVieV]

Many thanks! Very few channels for DB2 are also in good English) P.S. Do you answer questions on the channel?

[@DISCOVERDB2]

I always try to answer comments, feel free to ask away.

[@monishpatil3420]

Hey Nice explanatory video on reorg, i had one doubt, what if i accidentally perform an offline reorg in Prod environment during working hours, and what if i abort it in between without waiting for it to complete... Will database crash in such scenario?? if yes how do i get back the database running in Prod.

[@shubhamshahane6532]

Hello Sir, Very usefull information about reorg. I have one question : During offline reorg system get down or get crashed what happen will we able to access table ? Or we have to restore from tempspace1 (mostly this will not happend but senario asking in interview question)

[@yashtiwari4348]

Thank you... it was a very well explained video... After Online reorg do we need to run reorg index command every-time... ?**

[@DISCOVERDB2]

Not necessarily, many people lean on REORGCHK to tell them when to reorganize what tables or indexes (a script could be written to interpret the output and automatically kick off a reorg). But if I am manually running a reorg on a specific table I normally do both table and index and follow up with a runstats.

[@yashtiwari4348]

Ohhkay... thank you...

[@aravindachalla4398]

What if offline reorg interrupt ?

[@DISCOVERDB2]

I’m not sure I understand your question? If the offline reorg was interrupted and stopped abnormally, you can just issue the same reorg command again and it should start over from the beginning.