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Enum on-disk format

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I'm trying to better understand the internals of Postgres, and I'm looking at the enum type. The docs say that an enum value is stored on disk as 4 bytes. But enum_send() returns a bytea representing the actual text of the value and not the index of that value. So what step am I missing here?

Also, is there a way to see the raw data for the tuple on a page? I was using pageinspect to try to figure out what was happening on the disk. The get_raw_page function returns the entire page and heap_page_items will allow me to find the substring that represents a given tuple. But the rows were much wider than I thought they would be, 28 bytes + 2 byte spacer to store 4 bytes of data. Is there any way to see which bytes of an item pointer actually map to columns in a table? And where can I find more info on how Postgres stores tuples?

Scott Bailey

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