Re: Number of attributes in HeapTupleHeader - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: Number of attributes in HeapTupleHeader
Date
Msg-id 200206121823.g5CINGq14824@candle.pha.pa.us
Whole thread Raw
In response to Re: Number of attributes in HeapTupleHeader  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Tom Lane wrote:
> I said:
> > Sorry, you used up your chance at claiming that t_hoff is dispensable.
> > If we apply your already-submitted patch, it isn't.
> 
> Wait, I take that back.  t_hoff is important to distinguish how much
> bitmap padding there is on a particular tuple --- but that's really
> only interesting as long as we aren't forcing dump/initdb/reload.
> If we are changing anything else about tuple headers, then that
> argument becomes irrelevant anyway.
> 
> However, I'm still concerned about losing safety margin by removing
> "redundant" fields.

I just wanted to comment that redundancy in the tuple header, while
adding a very marginal amount to stability, is really too high a cost. 
If we can save 4 bytes on every row stored, I think that is a clear win.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
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