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Re: [HACKERS] Re: [DOCS] Re: FE/BE protocol revision patcht

From: Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us>
To: maillist(at)candle(dot)pha(dot)pa(dot)us (Bruce Momjian)
Cc: lockhart(at)alumni(dot)caltech(dot)edu, dg(at)illustra(dot)com, tgl(at)sss(dot)pgh(dot)pa(dot)us, hackers(at)postgreSQL(dot)org
Subject: Re: [HACKERS] Re: [DOCS] Re: FE/BE protocol revision patcht
Date: 1998-07-12 22:04:27
Message-ID: 199807122204.SAA08329@candle.pha.pa.us (view raw or flat)
Thread:
Lists: pgsql-hackers
> > 
> > > > > Comments?  I am willing to change it.
> > > >
> > > > An int 4 atttypmod should be fine. A bit of overhead perhaps, but 
> > > > who quibles about a few bytes these days? And, perhaps there is a 
> > > > use.
> > > Yea, no one commented, so it stays an int2 until someone finds a type
> > > that needs more than a two-byte atttypmod.  Right now, it fits the 
> > > need.
> > 
> > Well, I didn't comment because I haven't yet worked out the issues. But
> > I'll go with Bruce's and David's inclination that we should shoehorn
> > numeric()/decimal() into something like the existing atttypmod field
> > rather than trying for "the general solution" which btw isn't obvious
> > how to do.
> > 
> > However, I don't think that 16 bits vs 32 bits is an issue at all
> > performance-wise, and I'd to see atttypmod go to 32 bits just to give a
> > little breathing room. I'm already using int32 to send attypmod to the
> > new char/varchar sizing functions.
> 
> OK, I can change it, but it is not easy.  Will take time.
> 
> > 
> > Can we go to int32 on atttypmod? I'll try to break it up into two
> > sub-fields to implement numeric().
> > 
> > btw, anyone know of a package for variable- and large-precision
> > numerics? I have looked at the GNU gmp package, but it looks to me that
> > it probably won't fit into the db backend without lots of overhead. Will
> > probably try to use the int64 package in contrib for now...
> > 
> >                       - Tom
> > 

OK, I have made the change so we now have 32-bit atttypmod fields.  We
were already passing it as int32 to the clients, so no changes to libpq.

This change will required all developers to do a new initdb.

I had forgotten how much code there is for atttypmod.  I did it in
stages, but forgot how intertwined it is in much of the code.  I used a
consistent naming convention, so it was very easy to change all
references very quickly.

-- 
Bruce Momjian                          |  830 Blythe Avenue
maillist(at)candle(dot)pha(dot)pa(dot)us              |  Drexel Hill, Pennsylvania 19026
  +  If your life is a hard drive,     |  (610) 353-9879(w)
  +  Christ can be your backup.        |  (610) 853-3000(h)

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Subject: atttypmod now 32 bits, interface change
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