Find best choice for degree for B+ tree,

Question

Consider a relation R(A B C) with attribute size of A as 8 bytes. Disk block size is 512 bytes and block pointer is 8 bytes. The best choice for degree (maximum value) for B⁺ tree, if B⁺ tree was used for creating indexing on R(A B C) is _________.

Comments

its a made easy test series question. I am getting 32 max degree but they have given 33 as max degree. please help me to find the correct ans.

Answer 1

Let p be degree of B+tree internal node:

(p-1) keys + p Block pointers  should fit in a block ie  (p-1) keys + p Block pointers  size <=512

(2p-1) * 8<=512

p<=65/2 

p=32

if u take p=33node size becomes 520 bytes so not possible to fit in a block hence correct ans is 32

Comments

Degree should be order + 1

And you computed order to be 32.

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@Amsar:  any reference this. " Degree should be order + 1"

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order is number of children

Degree is number of adjacent nodes i.e -  number of chiildren + parent node

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oh its simple graph concept.

Thanks Amsar Sokt :)

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@amsar sokt,

https://www.google.co.in/search?q=dwgree+of+node+in+tree

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@anurag_s By the reference u hv provided can we say degree=order of the tree?

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Yes

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order = max. no. of children any node can have??