From: Tom Lane <tgl@sss.pgh.pa.us>
To: Paul A Jungwirth <pj@illuminatedcomputing.com>
cc: Alvaro Herrera <alvherre@2ndquadrant.com>,
        Pavel Stehule <pavel.stehule@gmail.com>,
        Jeff Davis <pgsql@j-davis.com>,
        Pgsql Hackers <pgsql-hackers@postgresql.org>
Subject: Re: range_agg
In-reply-to: <15764.1583615192@sss.pgh.pa.us>
References: <20200304022849.GA5402@alvherre.pgsql>
 <13800.1583612399@sss.pgh.pa.us> <15764.1583615192@sss.pgh.pa.us>
Comments: In-reply-to Tom Lane <tgl@sss.pgh.pa.us>
	message dated "Sat, 07 Mar 2020 16:06:32 -0500"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <16396.1583616058.1@sss.pgh.pa.us>
Date: Sat, 07 Mar 2020 16:20:58 -0500
Message-ID: <16397.1583616058@sss.pgh.pa.us>
Precedence: bulk

I wrote:
> Actually ... have you given any thought to just deciding that ranges and
> multiranges are the same type?  That is, any range can now potentially
> contain multiple segments?  That would eliminate a whole lot of the
> tedious infrastructure hacking involved in this patch, and let you focus
> on the actually-useful functionality.

Also, this would allow us to remove at least one ugly misfeature:

regression=# select '[1,2]'::int4range + '[3,10)'::int4range;
 ?column? 
----------
 [1,10)
(1 row)

regression=# select '[1,2]'::int4range + '[4,10)'::int4range;
ERROR:  result of range union would not be contiguous

If the result of range_union can be a multirange as easily as not,
we would no longer have to throw an error here.

			regards, tom lane