Re: [HACKERS] Pluggable storage

> 1. Table AM with a 6-byte TID.
> 2. Table AM with a custom locator format, which could be TID-like.
> 3. Table AM with no locators.

Currently TID has its own type in system catalog. Seems, it's possible that 
storage claims type of TID which it uses. Then, AM could claim it too, so the 
core based on that information could solve the question about AM-storage 
compatibility. Storage could also claim that it hasn't TID type at all so it 
couldn't be used with any access method, use case: compressed column oriented 
storage.

As I remeber, only GIN depends on TID format, other indexes use it as opaque 
type. Except, at least, btree and GiST - they believ that internal pointers are 
the same as outer (to heap)

Another dubious part - BitmapScan.

-- 
Teodor Sigaev                                   E-mail: teodor@sigaev.ru
  WWW: http://www.sigaev.ru/