RE: unique indexes on partitioned tables

Hi.

I tried this feature with the latest snapshot. When I executed the following SQL statement, multiple primary keys were created on the partition.
Is this the intended behavior?

-- test
postgres=> CREATE TABLE part1(c1 INT PRIMARY KEY, c2 INT, c3 VARCHAR(10)) PARTITION BY RANGE(c1) ;
CREATE TABLE
postgres=> CREATE TABLE part1v1 (LIKE part1) ;
CREATE TABLE
postgres=> ALTER TABLE part1v1 ADD CONSTRAINT pk_part1v1 PRIMARY KEY (c1, c2) ;
ALTER TABLE
postgres=> ALTER TABLE part1 ATTACH PARTITION part1v1 FOR VALUES FROM (100) TO (200) ;
ALTER TABLE
postgres=> \d part1v1
Table "public.part1v1"
Column | Type | Collation | Nullable | Default
--------+-----------------------+-----------+----------+---------
c1 | integer | | not null |
c2 | integer | | not null |
c3 | character varying(10) | | |
Partition of: part1 FOR VALUES FROM (100) TO (200)
Indexes:
"part1v1_pkey" PRIMARY KEY, btree (c1)
"pk_part1v1" PRIMARY KEY, btree (c1, c2)

Regards,

Noriyoshi Shinoda

-----Original Message-----
From: Amit Langote [mailto:Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp]
Sent: Tuesday, February 20, 2018 6:24 PM
To: Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>; Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com>; Jaime Casanova <jaime(dot)casanova(at)2ndquadrant(dot)com>
Cc: Jesper Pedersen <jesper(dot)pedersen(at)redhat(dot)com>; Pg Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: unique indexes on partitioned tables

Hi.

On 2018/02/20 5:45, Alvaro Herrera wrote:
> I pushed this now, with fixes for the last few comments there were.

I noticed with the commit that, while ON CONFLICT (conflict_target) DO UPDATE gives a less surprising error message by catching it in the parser, ON CONFLICT (conflict_target) DO NOTHING will go into the executor without the necessary code to handle the case. Example:

create table p (a int primary key, b text) partition by list (a); create table p12 partition of p for values in (1, 2); create table p3 partition of p (a unique) for values in (3);

insert into p values (1, 'a') on conflict (a) do nothing;
ERROR: unexpected failure to find arbiter index

Attached is a patch to fix that. Actually, there are two -- one that adjusts the partitioned table tests in insert_conflict.sql to have a partitioned unique index and another that fixes the code.

I suppose we'd need to apply this temporarily until we fix the ON CONFLICT
(conflict_target) case to be able to use partitioned indexes.

Thanks,
Amit