Do pin_count and dirty have to be in the Page interface in a DB?

[GavinRay97]

I'm trying to understand whether there is a special reason for putting pin_count and dirty on the Page interface -- or if it was just a convenient design choice?

Why I ask this question is because, if I understand right, this information is only relevant as part of the "frame table" in the Buffer Manager?

Page my_page = Page {};
// Here, the pin_count and dirty bit doesn't mean anything

Is the below (or something similar) also a valid design?

abstract class Page {
    byte[] data;
    PageId pageId;
    int lsn;
}

class Frame {
   PageId pageId;
   FrameId frameId;
   int pinCount;
   boolean isDirty;
}

class BufferPoolManager {
   Map<PageId, Frame> frameTable;
}

[skyzh]

The design looks good to me! That's all about design choices.

[GavinRay97]

Thanks for the feedback, just wanted to make sure I understand 👍