To: PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Reply-To: jesper.pedersen@redhat.com
Cc: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
From: Jesper Pedersen <jesper.pedersen@redhat.com>
Subject: COLLATE: Hash partition vs UPDATE
Organization: Red Hat
Message-ID: <a620f85a-42ab-e0f3-3337-b04b97e2e2f5@redhat.com>
Date: Mon, 8 Apr 2019 12:33:55 -0400
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Hi,

The following case

-- test.sql --
CREATE TABLE test (a text PRIMARY KEY, b text) PARTITION BY HASH (a);
CREATE TABLE test_p0 PARTITION OF test FOR VALUES WITH (MODULUS 2, 
REMAINDER 0);
CREATE TABLE test_p1 PARTITION OF test FOR VALUES WITH (MODULUS 2, 
REMAINDER 1);
-- CREATE INDEX idx_test_b ON test USING HASH (b);

INSERT INTO test VALUES ('aaaa', 'aaaa');

-- Regression
UPDATE test SET b = 'bbbb' WHERE a = 'aaaa';
-- test.sql --

fails on master, which includes [1], with


psql:test.sql:9: ERROR:  could not determine which collation to use for 
string hashing
HINT:  Use the COLLATE clause to set the collation explicitly.


It passes on 11.x.

I'll add it to the open items list.

[1] 
https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=5e1963fb764e9cc092e0f7b58b28985c311431d9

Best regards,
  Jesper