hash_array_extended() needs to pass down collation

From 171c58bc37c211cab11f6b588220e9e773f67e67 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Mon, 2 Nov 2020 08:24:28 +0100
Subject: [PATCH] Enable hash partitioning of text arrays

hash_array_extended() needs to pass PG_GET_COLLATION() to the hash
function of the element type.  Otherwise, the hash function of a
collation-aware data type such as text will error out, since the
introduction of nondeterministic collation made hash functions require
a collation, too.

The consequence of this is that before this change, hash partitioning
using an array over text in the partition key would not work.
---
 src/backend/utils/adt/arrayfuncs.c            |  2 +-
 .../regress/expected/collate.icu.utf8.out     | 50 +++++++++++++++++++
 src/test/regress/sql/collate.icu.utf8.sql     | 26 ++++++++++
 3 files changed, 77 insertions(+), 1 deletion(-)

diff --git a/src/backend/utils/adt/arrayfuncs.c b/src/backend/utils/adt/arrayfuncs.c
index 392445ea03..a7ea7656c7 100644
--- a/src/backend/utils/adt/arrayfuncs.c
+++ b/src/backend/utils/adt/arrayfuncs.c
@@ -4071,7 +4071,7 @@ hash_array_extended(PG_FUNCTION_ARGS)
 	typalign = typentry->typalign;
 
 	InitFunctionCallInfoData(*locfcinfo, &typentry->hash_extended_proc_finfo, 2,
-							 InvalidOid, NULL, NULL);
+							 PG_GET_COLLATION(), NULL, NULL);
 
 	/* Loop over source data */
 	nitems = ArrayGetNItems(ndims, dims);
diff --git a/src/test/regress/expected/collate.icu.utf8.out b/src/test/regress/expected/collate.icu.utf8.out
index 2b86ce9028..70133df804 100644
--- a/src/test/regress/expected/collate.icu.utf8.out
+++ b/src/test/regress/expected/collate.icu.utf8.out
@@ -1215,6 +1215,30 @@ SELECT * FROM test6 WHERE b = 'äbc' COLLATE ctest_nondet;
  2 | äbc
 (2 rows)
 
+-- same with arrays
+CREATE TABLE test6a (a int, b text[]);
+INSERT INTO test6a VALUES (1, ARRAY[U&'\00E4bc']);
+INSERT INTO test6a VALUES (2, ARRAY[U&'\0061\0308bc']);
+SELECT * FROM test6a;
+ a |   b   
+---+-------
+ 1 | {äbc}
+ 2 | {äbc}
+(2 rows)
+
+SELECT * FROM test6a WHERE b = ARRAY['äbc'] COLLATE ctest_det;
+ a |   b   
+---+-------
+ 1 | {äbc}
+(1 row)
+
+SELECT * FROM test6a WHERE b = ARRAY['äbc'] COLLATE ctest_nondet;
+ a |   b   
+---+-------
+ 1 | {äbc}
+ 2 | {äbc}
+(2 rows)
+
 CREATE COLLATION case_sensitive (provider = icu, locale = '');
 CREATE COLLATION case_insensitive (provider = icu, locale = '@colStrength=secondary', deterministic = false);
 SELECT 'abc' <= 'ABC' COLLATE case_sensitive, 'abc' >= 'ABC' COLLATE case_sensitive;
@@ -1842,6 +1866,19 @@ SELECT (SELECT count(*) FROM test22_0) = (SELECT count(*) FROM test22_1);
  t
 (1 row)
 
+-- same with arrays
+CREATE TABLE test22a (a int, b text[] COLLATE case_sensitive) PARTITION BY HASH (b);
+CREATE TABLE test22a_0 PARTITION OF test22a FOR VALUES WITH (MODULUS 2, REMAINDER 0);
+CREATE TABLE test22a_1 PARTITION OF test22a FOR VALUES WITH (MODULUS 2, REMAINDER 1);
+INSERT INTO test22a VALUES (1, ARRAY['def']);
+INSERT INTO test22a VALUES (2, ARRAY['DEF']);
+-- they end up in different partitions
+SELECT (SELECT count(*) FROM test22a_0) = (SELECT count(*) FROM test22a_1);
+ ?column? 
+----------
+ t
+(1 row)
+
 CREATE TABLE test23 (a int, b text COLLATE case_insensitive) PARTITION BY HASH (b);
 CREATE TABLE test23_0 PARTITION OF test23 FOR VALUES WITH (MODULUS 2, REMAINDER 0);
 CREATE TABLE test23_1 PARTITION OF test23 FOR VALUES WITH (MODULUS 2, REMAINDER 1);
@@ -1854,6 +1891,19 @@ SELECT (SELECT count(*) FROM test23_0) <> (SELECT count(*) FROM test23_1);
  t
 (1 row)
 
+-- same with arrays
+CREATE TABLE test23a (a int, b text[] COLLATE case_insensitive) PARTITION BY HASH (b);
+CREATE TABLE test23a_0 PARTITION OF test23a FOR VALUES WITH (MODULUS 2, REMAINDER 0);
+CREATE TABLE test23a_1 PARTITION OF test23a FOR VALUES WITH (MODULUS 2, REMAINDER 1);
+INSERT INTO test23a VALUES (1, ARRAY['def']);
+INSERT INTO test23a VALUES (2, ARRAY['DEF']);
+-- they end up in the same partition (but it's platform-dependent which one)
+SELECT (SELECT count(*) FROM test23a_0) <> (SELECT count(*) FROM test23a_1);
+ ?column? 
+----------
+ t
+(1 row)
+
 CREATE TABLE test30 (a int, b char(3) COLLATE case_insensitive) PARTITION BY LIST (b);
 CREATE TABLE test30_1 PARTITION OF test30 FOR VALUES IN ('abc');
 INSERT INTO test30 VALUES (1, 'abc');
diff --git a/src/test/regress/sql/collate.icu.utf8.sql b/src/test/regress/sql/collate.icu.utf8.sql
index 67de7d9794..9cee3d0042 100644
--- a/src/test/regress/sql/collate.icu.utf8.sql
+++ b/src/test/regress/sql/collate.icu.utf8.sql
@@ -483,6 +483,14 @@ CREATE TABLE test6 (a int, b text);
 SELECT * FROM test6 WHERE b = 'äbc' COLLATE ctest_det;
 SELECT * FROM test6 WHERE b = 'äbc' COLLATE ctest_nondet;
 
+-- same with arrays
+CREATE TABLE test6a (a int, b text[]);
+INSERT INTO test6a VALUES (1, ARRAY[U&'\00E4bc']);
+INSERT INTO test6a VALUES (2, ARRAY[U&'\0061\0308bc']);
+SELECT * FROM test6a;
+SELECT * FROM test6a WHERE b = ARRAY['äbc'] COLLATE ctest_det;
+SELECT * FROM test6a WHERE b = ARRAY['äbc'] COLLATE ctest_nondet;
+
 CREATE COLLATION case_sensitive (provider = icu, locale = '');
 CREATE COLLATION case_insensitive (provider = icu, locale = '@colStrength=secondary', deterministic = false);
 
@@ -685,6 +693,15 @@ CREATE TABLE test22_1 PARTITION OF test22 FOR VALUES WITH (MODULUS 2, REMAINDER
 -- they end up in different partitions
 SELECT (SELECT count(*) FROM test22_0) = (SELECT count(*) FROM test22_1);
 
+-- same with arrays
+CREATE TABLE test22a (a int, b text[] COLLATE case_sensitive) PARTITION BY HASH (b);
+CREATE TABLE test22a_0 PARTITION OF test22a FOR VALUES WITH (MODULUS 2, REMAINDER 0);
+CREATE TABLE test22a_1 PARTITION OF test22a FOR VALUES WITH (MODULUS 2, REMAINDER 1);
+INSERT INTO test22a VALUES (1, ARRAY['def']);
+INSERT INTO test22a VALUES (2, ARRAY['DEF']);
+-- they end up in different partitions
+SELECT (SELECT count(*) FROM test22a_0) = (SELECT count(*) FROM test22a_1);
+
 CREATE TABLE test23 (a int, b text COLLATE case_insensitive) PARTITION BY HASH (b);
 CREATE TABLE test23_0 PARTITION OF test23 FOR VALUES WITH (MODULUS 2, REMAINDER 0);
 CREATE TABLE test23_1 PARTITION OF test23 FOR VALUES WITH (MODULUS 2, REMAINDER 1);
@@ -693,6 +710,15 @@ CREATE TABLE test23_1 PARTITION OF test23 FOR VALUES WITH (MODULUS 2, REMAINDER
 -- they end up in the same partition (but it's platform-dependent which one)
 SELECT (SELECT count(*) FROM test23_0) <> (SELECT count(*) FROM test23_1);
 
+-- same with arrays
+CREATE TABLE test23a (a int, b text[] COLLATE case_insensitive) PARTITION BY HASH (b);
+CREATE TABLE test23a_0 PARTITION OF test23a FOR VALUES WITH (MODULUS 2, REMAINDER 0);
+CREATE TABLE test23a_1 PARTITION OF test23a FOR VALUES WITH (MODULUS 2, REMAINDER 1);
+INSERT INTO test23a VALUES (1, ARRAY['def']);
+INSERT INTO test23a VALUES (2, ARRAY['DEF']);
+-- they end up in the same partition (but it's platform-dependent which one)
+SELECT (SELECT count(*) FROM test23a_0) <> (SELECT count(*) FROM test23a_1);
+
 CREATE TABLE test30 (a int, b char(3) COLLATE case_insensitive) PARTITION BY LIST (b);
 CREATE TABLE test30_1 PARTITION OF test30 FOR VALUES IN ('abc');
 INSERT INTO test30 VALUES (1, 'abc');
-- 
2.28.0