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Re: Optional Oid

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Manfred Koizar <mkoi-pg(at)aon(dot)at>
Cc: pgsql-patches(at)postgresql(dot)org
Subject: Re: Optional Oid
Date: 2002-07-20 05:13:34
Message-ID: 200207200513.g6K5DYh17611@candle.pha.pa.us (view raw or flat)
Thread:
Lists: pgsql-patches
New version applied.


---------------------------------------------------------------------------

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.
> 

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman(at)candle(dot)pha(dot)pa(dot)us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026

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