Portal | Manuals | References | Downloads | Info | Programs | JCLs | Mainframe wiki | Quick Ref
IBM Mainframe Computers Forums Index
 
Register
 
IBM Mainframe Computers Forums Index Mainframe: Search IBM Mainframe Forum: FAQ Memberlist Profile Log in to check your private messages Log in
 
How does a select Query Works?

 
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> DB2
View previous topic :: :: View next topic  
Author Message
mailsaurabh.tripathi

New User


Joined: 22 May 2008
Posts: 56
Location: hyderabad

PostPosted: Tue Aug 24, 2010 7:38 pm    Post subject: How does a select Query Works?
Reply with quote

Hi

I need to decide that do we need commit's in select queries?
I belive with commit, the page is returned to the disk. As in case of select, the data will not change, is commit required? Also we if don't do a commit, what will happen to the rows fetchwd into the bufferpool? How does DB2 clears them from BP?
To undertand these question, i think it's necesary to understand how does a select works.
Please help me with these questions.

Regards
Saurabh Tripathi
Back to top
View user's profile Send private message

dbzTHEdinosauer

Global Moderator


Joined: 20 Oct 2006
Posts: 6970
Location: porcelain throne

PostPosted: Tue Aug 24, 2010 8:01 pm    Post subject:
Reply with quote

Read thru this and if you have any questions,
come back and I will give you more links.
Back to top
View user's profile Send private message
mailsaurabh.tripathi

New User


Joined: 22 May 2008
Posts: 56
Location: hyderabad

PostPosted: Tue Aug 24, 2010 8:56 pm    Post subject:
Reply with quote

Thnx for the wonderful link.
Please explain, how does a select query works internally, i.e the steps followed by DB2 to process a select query.
Back to top
View user's profile Send private message
dbzTHEdinosauer

Global Moderator


Joined: 20 Oct 2006
Posts: 6970
Location: porcelain throne

PostPosted: Tue Aug 24, 2010 9:12 pm    Post subject:
Reply with quote

if you do not want to peruse the manuals (link top of the page)
you can run EXPLAINs, which will tell you exactly how each query runs.
Back to top
View user's profile Send private message
View previous topic :: :: View next topic  
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> DB2 All times are GMT + 6 Hours
Page 1 of 1

 

Search our Forum:

Similar Topics
Topic Author Forum Replies Posted
No new posts SELECT TO MULIPLE OUTFIL speermb DFSORT/ICETOOL 5 Fri Mar 23, 2018 10:44 pm
No new posts Query to compare 2 values of 1 column... Poha Eater DB2 13 Fri Mar 09, 2018 10:45 am
No new posts How to replace the below query? pkmurali DB2 12 Tue Feb 27, 2018 9:51 pm
No new posts Need Guidance regarding UPDATE query Poha Eater DB2 3 Mon Feb 12, 2018 11:35 pm
No new posts Query to skip Max time-stamp and fetc... vickey_dw DB2 8 Sun Jan 28, 2018 1:09 am

Facebook
Back to Top
 
Job Vacancies | Forum Rules | Bookmarks | Subscriptions | FAQ | Polls | Contact Us