What should be answer 51 or 52?

Question

A B+ tree index is built on the key ‘CS’ attribute of the relation ME16. The attribute ‘CS’ is of length 32 bytes, disk blocks are of size 2048 bytes and index pointers are of size 8 bytes. The number of pointers per node is _______.

Comments

let #keys per block = x

$\therefore$ 32(x) + 8(x+1) <= 2048

$\therefore$ 40x + 8 <= 2048

$\therefore$ 40x <= 2040

$\therefore$ x = 51  (without any doubt)

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Eg taken from - https://courses.cs.washington.edu/courses/cse326/08sp/lectures/11-b-trees.pdf

So, node structure is like : <index-pointer, key, index-pointer, key,............................, index-pointer>

and not like : <key,index pointer>

Thus 52 is correct, and the solution given is also correct

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@Sushant, you have thought of 'x' as no of keys, thus there are 51 keys, but there are 52 pointers(per node)