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CS5540
HW1, question 5

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se1k1h1mawar1 Posts: 121	Posted 17:51 Mar 12, 2017 \| The below material from our HW1 does not seem familiar to me. Could someone please confirm that this will be on our midterm exam? Thank you in advance, 5. Assume that you have just built a dense B+ tree index using Alternative 2 on a heap file containing 40,000 records. The key field for this B+ tree index is 20- bytestring, and it is a candidate key. Pointers (i.e., record ids and page ids) are (at most) 10-byte values. The size of one disk page is 2000 bytes. The index was built in a bottom-up fashion using the bulk loading algorithm, and the nodes at each level were filled up as much as possible. 1) How many levels does the resulting tree have? 2) For each level of the tree, how many nodes are at that level? 3) How many levels would the resulting tree have if key compression is used and it reduces the average size of each key in an entry to 10 bytes? 4) How many levels would be the resulting tree have without key compression but with all pages 70% full?
se1k1h1mawar1 Posts: 121	Posted 22:08 Mar 13, 2017 \| se1k1h1mawar1 wrote: The below material from our HW1 does not seem familiar to me. Could someone please confirm that this will be on our midterm exam? Thank you in advance, 5. Assume that you have just built a dense B+ tree index using Alternative 2 on a heap file containing 40,000 records. The key field for this B+ tree index is 20- bytestring, and it is a candidate key. Pointers (i.e., record ids and page ids) are (at most) 10-byte values. The size of one disk page is 2000 bytes. The index was built in a bottom-up fashion using the bulk loading algorithm, and the nodes at each level were filled up as much as possible. 1) How many levels does the resulting tree have? 2) For each level of the tree, how many nodes are at that level? 3) How many levels would the resulting tree have if key compression is used and it reduces the average size of each key in an entry to 10 bytes? 4) How many levels would be the resulting tree have without key compression but with all pages 70% full? Now it looks very familiar. This should be on our midterm, yes.
mjaved3 Posts: 4	Posted 14:54 Mar 14, 2017 \| se1k1h1mawar1 wrote: se1k1h1mawar1 wrote: The below material from our HW1 does not seem familiar to me. Could someone please confirm that this will be on our midterm exam? Thank you in advance, 5. Assume that you have just built a dense B+ tree index using Alternative 2 on a heap file containing 40,000 records. The key field for this B+ tree index is 20- bytestring, and it is a candidate key. Pointers (i.e., record ids and page ids) are (at most) 10-byte values. The size of one disk page is 2000 bytes. The index was built in a bottom-up fashion using the bulk loading algorithm, and the nodes at each level were filled up as much as possible. 1) How many levels does the resulting tree have? 2) For each level of the tree, how many nodes are at that level? 3) How many levels would the resulting tree have if key compression is used and it reduces the average size of each key in an entry to 10 bytes? 4) How many levels would be the resulting tree have without key compression but with all pages 70% full? Now it looks very familiar. This should be on our midterm, yes. Can you kindly explain in short the answer to this question? Thanks.