Database Systems · intro
Pages vs Frames
Map students pages (P1–P4 from the disk lesson) into fixed RAM frames with a page table, pins, and dirty flags — foundation for replacement policies.
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P1 Ada/Bob · P2 Dan/Eve · P4 index · 4 frames only
Disk (pages)
P0
P1
P2
P3
P4
P5
Buffer pool (frames)
F0empty
F1empty
F2empty
F3empty
Page table
No resident pages yet
The problem
Table students already spans multiple 8 KB pages (P1, P2, …) on disk, but RAM only has 4 frames. We cache hot pages, not the whole file.
Key idea
We never load the whole database. We cache hot pages in a small pool of frames.
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