From: Christophe Pettus <xof@thebuild.com>
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Subject: Overlapping values (?) in multi-column partitioned tables
Message-Id: <2FAC43EB-7E04-476A-BEBE-39CDBCA0EDCC@thebuild.com>
Date: Tue, 10 Sep 2024 15:13:47 -0700
To: pgsql-general <pgsql-general@postgresql.org>
Archived-At: <https://www.postgresql.org/message-id/2FAC43EB-7E04-476A-BEBE-39CDBCA0EDCC%40thebuild.com>
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Hi,

I am clearly not understanding something.  Consider:

> xof=3D# create table t (pk bigint not null, ts timestamp not null) =
partition by range (ts, pk);
> CREATE TABLE
> xof=3D# create table t1 partition of t for values from =
('2024-01-01'::timestamp, minvalue) to ('2024-02-01'::timestamp, =
maxvalue);
> CREATE TABLE
> xof=3D# create table t2 partition of t for values from =
('2024-02-01'::timestamp, minvalue) to ('2024-03-01'::timestamp, =
maxvalue);
> ERROR:  partition "t2" would overlap partition "t1"
> LINE 1: ...on of t for values from ('2024-02-01'::timestamp, minvalue) =
...
>                                                              ^
> xof=3D#=20

In what way do those partitions overlap?  In other words, there does not =
appear to be a value of (ts, pk) having '2024-01-01'::timestamp <=3D ts =
< '2024-03-01'::timestamp for any pk where it would be ambiguous which =
partition that row would go into.  (I'm imagining it on a cartesian =
plane, and there isn't any overlap between the rectangles those =
partition boundaries define.)

I'm obviously missing something, but... what?  Thank you!=