Skip site navigation (1) Skip section navigation (2)

Re: Transform groups (more FE/BE protocol issues)

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Zeugswetter Andreas SB SD" <ZeugswetterA(at)spardat(dot)at>
Cc: "Peter Eisentraut" <peter_e(at)gmx(dot)net>,pgsql-hackers(at)postgreSQL(dot)org, pgsql-interfaces(at)postgreSQL(dot)org
Subject: Re: Transform groups (more FE/BE protocol issues)
Date: 2003-05-05 16:54:00
Message-ID: 28645.1052153640@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-hackerspgsql-interfaces
"Zeugswetter Andreas SB SD" <ZeugswetterA(at)spardat(dot)at> writes:
> Yes, all sounds very reasonable. I would make the field wide enough to
> carry a pg_type.oid.

> A few values (that should optimally not conflict with pg_type oid's) could
> carry special meaning like 0 text, 1 native binary ...

Well, this is exactly why the contents are *not* OIDs.  Zero isn't a
valid OID and I don't like assuming that 1 is either.  Also if you want
to think that the codes might be forced by outside considerations (like
odbc standards) then OID is a bad idea.

If we were really doing this in a general fashion (which is not
happening for 7.4 ;-)) I would envision a system catalog that describes
transform groups --- but it would have a non-OID column that carries the
group ID to be used at the protocol level.  We can pretty much choose
the width of that column at will --- either 1, 2, or 4 bytes could be
argued for, depending on how you want to make the tradeoff between
bandwidth and flexibility.

I'm leaning towards 1 or 2 bytes myself.  I have a hard time envisioning
huge numbers of transform groups.

			regards, tom lane


In response to

pgsql-hackers by date

Next:From: Tom LaneDate: 2003-05-05 16:55:47
Subject: Re: Why are triggers semi-deferred?
Previous:From: Philip WarnerDate: 2003-05-05 16:23:54
Subject: Re: Why are triggers semi-deferred?

pgsql-interfaces by date

Next:From: Peter EisentrautDate: 2003-05-06 00:31:39
Subject: Re: Transform groups (more FE/BE protocol issues)
Previous:From: Zeugswetter Andreas SB SDDate: 2003-05-05 16:13:57
Subject: Re: Transform groups (more FE/BE protocol issues)

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group