Re: Optional Oid

New version applied.

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Manfred Koizar wrote:
> Here is a preview of a patch which shall eventually further reduce
> heap tuple header size by four bytes for tables created WITHOUT OIDS.
>
> t_oid is eliminated from the start of struct HeapTupleHeader. If an
> oid is needed, it is added at the end of the struct (after the null
> bitmap, if present).
>
> Per Tom Lane's suggestion the information whether a tuple has an oid
> or not is carried in the tuple descriptor. For debugging reasons
> tdhasoid is of type char, not bool. There are predefined values for
> WITHOID, WITHOUTOID and UNDEFOID.
>
> This patch has been generated against a cvs snapshot from last week
> and I don't expect it to apply cleanly to current sources. While I
> post it here for public review, I'm working on a new version against a
> current snapshot. (There's been heavy activity recently; hope to
> catch up some day ...)
>
> This is a long patch; if it is too hard to swallow, I can provide it
> in smaller pieces:
>
> Part 1: Accessor macros
> Part 2: tdhasoid in TupDesc
> Part 3: Regression test
> Part 4: Parameter withoid to heap_addheader
> Part 5: Eliminate t_oid from HeapTupleHeader
>
> Part 2 is the most hairy part because of changes in the executor and
> even in the parser; the other parts are straightforward.
>
> Up to part 4 the patched postmaster stays binary compatible to
> databases created with an unpatched version. Part 5 is small (100
> lines) and finally breaks compatibility.
>

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