In a relational database, a B+ Tree Index is to be constructed for a relation on a key field. In a B+ Tree, a Node Pointer points to a sub-tree and a Data Record Pointer points to a block of database records.
Let, Node size = 4096 bytes, Node Pointer size = 10 bytes, Search Key Field size = 11 bytes and Data Record Pointer size = 12 bytes.
The maximum number of Node Pointers that can be present in a non-leaf node of the B+ Tree is ________ . (Answer in integer)
ANSWER
The maximum number of node pointers in a non-leaf node is 195.
Official answer: 195Source: Official answer key, GATE 2026 DA (IIT Guwahati)
In a B+ tree, a non-leaf (internal) node stores only node pointers and search keys. Data record pointers appear only in leaf nodes, so the 12-byte data record pointer plays no part in this question.
A non-leaf node with node pointers holds search keys. The node must fit in one block, so .
Simplify: , so and
must be a whole number, so the largest value is .
Check: for the node uses bytes, so it fits. For it uses bytes, so it does not fit.
KEY IDEA
An internal node with node pointers has search keys and no data record pointers. Solve and take the floor.
WATCH OUT FOR
Counting keys instead of gives , so by coincidence here but a wrong method. Adding the 12-byte data record pointer to a non-leaf node is also wrong, because those pointers are held only in leaf nodes. Forgetting to take the floor of is a third slip.
From the GATE 2026 DA paper. Every question of this paper · Download the full paper · All 3 Indexing questions, with notes
