0 votes 0 votes 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 _______. thor asked Jan 10, 2017 thor 489 views answer comment Share Follow See all 10 Comments See all 10 10 Comments reply Habibkhan commented Jan 10, 2017 reply Follow Share The question is incomplete as we know leaf node and internal node structure is different in case of B+ tree..So complete information should be given. 0 votes 0 votes thor commented Jan 10, 2017 reply Follow Share Key and index pointer are given. I think it's correct. 0 votes 0 votes Habibkhan commented Jan 10, 2017 reply Follow Share But the question is more meaningful if it is said record and block pointers as they have different meanings in B+ tree terminology.. 0 votes 0 votes thor commented Jan 10, 2017 reply Follow Share A index contains two fields <key,index pointer> Means size of an index entry = 40B and block size = 2048B, so within a block there can be 2048/40 index entries or pointers. 2048/40 = 51.something I think ans= 51, but given = 52 0 votes 0 votes Habibkhan commented Jan 10, 2017 reply Follow Share Yes u r right..To get block factor we take floor value not ceil..Hence 51 is correct.. 1 votes 1 votes thor commented Jan 10, 2017 reply Follow Share they have done : which one to consider true ? 0 votes 0 votes papesh commented Jan 10, 2017 reply Follow Share 51 is correct ! 0 votes 0 votes Sushant Gokhale commented Jan 14, 2017 reply Follow Share 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) 1 votes 1 votes braindead commented Jan 12, 2018 reply Follow Share 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 0 votes 0 votes braindead commented Jan 12, 2018 reply Follow Share @Sushant, you have thought of 'x' as no of keys, thus there are 51 keys, but there are 52 pointers(per node) 0 votes 0 votes Please log in or register to add a comment.