Why do B-trees stay balanced automatically as data is inserted?
B-trees rebalance through node splits: when a node fills past its capacity, it splits into two nodes and pushes a middle key up to the parent, which can itself split if it overflows. This keeps every leaf at the same depth from the root without requiring a separate rebalancing pass — the structure maintains its own balance as a direct consequence of how inserts are handled.
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What Actually Happens Inside a Database Index: The Data StructuresAn index trades disk I/O for lookup speed. Here's how B-trees, hash tables, and bitmap indexes each make that trade differently.
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