Horton

Re: unnesting multirange data types

Jonathan S. Katz <jkatz@postgresql.org>

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From: "Jonathan S. Katz" <jkatz@postgresql.org>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-06-09T23:00:24Z
Lists: pgsql-hackers 
On 6/9/21 4:56 PM, Alvaro Herrera wrote:
> On 2021-Jun-09, Jonathan S. Katz wrote:
> 
>> I did a couple more tests around this.
>>
>> As suspected, in PL/pgSQL, there is no way to unpack or iterate over a
>> multirange type.
> 
> Uh.  This is disappointing; the need for some way to unnest or unpack a
> multirange was mentioned multiple times in the range_agg thread.  I had
> assumed that there was some way to cast the multirange to a range array,
> or somehow convert it, but apparently that doesn't work.

Just to be pedantic with examples:

  SELECT datemultirange(
    daterange(current_date, current_date + 2),
    daterange(current_date + 5, current_date + 7))::daterange[];

  ERROR:  cannot cast type datemultirange to daterange[]
  LINE 1: ...2), daterange(current_date + 5, current_date + 7))::daterang...

IF there was an array to cast it into an array, we could then use the
array looping construct in PL/pgSQL, but if we could only choose one, I
think it'd be more natural/less verbose to have an "unnest".

> If the supporting pieces are mostly there, then I opine we should add
> something.

Agreed.

Jonathan

Commits

  1. Fix small inconsistencies in catalog definition of multirange operators

  2. Revert 29854ee8d1 due to buildfarm failures

  3. Copy-edit text for the pg_terminate_backend() "timeout" parameter.

  4. Add missing pg_description strings for pg_type entries.

  5. Fix pg_description entries for jsonb_to_record() and jsonb_to_recordset().

  6. docs: clarify JSONB operator descriptions

  7. Set procost to 10 for each of the pg_foo_is_visible() functions.

  8. Make use of LATERAL in information_schema.sequences view.

  9. Add pg_trigger_depth() function

  10. Add database comments to template0 and postgres databases, and improve