B-Tree Index — Pages, Splits, and Write-Ahead Log

B-Tree Index — Pages, Splits, and Write-Ahead Log An architecture diagram generated by Archify. Application · lookup key 251 · Architecture component Application lookup key 251 Root Page · boundaries 200 | 300 · B-Tree Index — fixed-size pages (8–16 KiB), depth O(log n) · start here Root Page boundaries 200 | 300 start here Internal Page · range 200–300 · B-Tree Index — fixed-size pages (8–16 KiB), depth O(log n) Internal Page range 200–300 Internal Page · range 300–400 · B-Tree Index — fixed-size pages (8–16 KiB), depth O(log n) Internal Page range 300–400 Leaf Page · keys 250–270 · B-Tree Index — fixed-size pages (8–16 KiB), depth O(log n) · holds key 251 Leaf Page keys 250–270 holds key 251 Leaf Page · keys 271–300 · B-Tree Index — fixed-size pages (8–16 KiB), depth O(log n) Leaf Page keys 271–300 Leaf Page · keys 333–345 · B-Tree Index — fixed-size pages (8–16 KiB), depth O(log n) · split on overflow Leaf Page keys 333–345 split on overflow Write-Ahead Log · append-only, fsync before apply · Architecture component · crash recovery Write-Ahead Log append-only, fsync before apply crash recovery Heap File · rows in no order · Architecture component · row storage Heap File rows in no order row storage lookup key 251 between 200 and 300 between 300 and 400 between 250 and 270 between 271 and 300 between 333 and 345 sibling pointer row pointer log page change first replay after crash B-Tree Index — fixed-size pages (8–16 KiB), depth O(log n) Legend Database External