clustering index



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clustering index

Postby makkena » Tue Apr 19, 2011 11:44 am

can some one pls provide me the best mnual for understanding wt is clustering index. i am not able to get the good one in google.
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Re: clustering index

 

Re: clustering index

Postby alexm » Tue Apr 19, 2011 4:59 pm

Question here is what's a "good one"...
Have a look at this excerpt of an IBM manual, or get an idea from this blog.

The important thing is:
[...] causes DB2 to insert the records as nearly as possible in the order of their index values [...]
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Re: clustering index

Postby Suny » Thu Apr 21, 2011 4:16 pm

I cannot point to a good manual (difficult to define whats good) but I will try to get you a start here. The logic is same as KSDS VSAM index logic.
Ok, So now you have a Db2 table without any index. You define an index now and do a Build index (possibly a reorg to get a correct sequence). The index values sequence will have the same sequence to DB2 rows. Now if you try to insert a row whose index falls somewhere in between , Db2 will try to insert the row in the corresponding location by utilizing the freespace in a page.
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