Remove complaints about COLLATE clauses in partition bound values.

transformPartitionBoundValue went out of its way to do the wrong
thing: there is no reason to complain about a non-matching COLLATE
clause in a partition boundary expression.  We're coercing the
bound expression to the target column type as though by an
implicit assignment, and the rules for implicit assignment say
that collations can be implicitly converted.

What we *do* need to do, and the code is not doing, is apply
assign_expr_collations() to the bound expression.  While this is
merely a definition disagreement, that is a bug that needs to be
back-patched, so I'll commit it separately.

Discussion: https://postgr.es/m/CAJV4CdrZ5mKuaEsRSbLf2URQ3h6iMtKD=hik8MaF5WwdmC9uZw@mail.gmail.com

1 files changed, 0 insertions, 44 deletions

diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 164312d60e2..6d2f36da2df 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -4184,50 +4184,6 @@ transformPartitionBoundValue(ParseState *pstate, Node *val,
 	Assert(!contain_var_clause(value));
 
 	/*
-	 * Check that the input expression's collation is compatible with one
-	 * specified for the parent's partition key (partcollation).  Don't throw
-	 * an error if it's the default collation which we'll replace with the
-	 * parent's collation anyway.
-	 */
-	if (IsA(value, CollateExpr))
-	{
-		Oid			exprCollOid = exprCollation(value);
-
-		/*
-		 * Check we have a collation iff it is a collatable type.  The only
-		 * expected failures here are (1) COLLATE applied to a noncollatable
-		 * type, or (2) partition bound expression had an unresolved
-		 * collation.  But we might as well code this to be a complete
-		 * consistency check.
-		 */
-		if (type_is_collatable(colType))
-		{
-			if (!OidIsValid(exprCollOid))
-				ereport(ERROR,
-						(errcode(ERRCODE_INDETERMINATE_COLLATION),
-						 errmsg("could not determine which collation to use for partition bound expression"),
-						 errhint("Use the COLLATE clause to set the collation explicitly.")));
-		}
-		else
-		{
-			if (OidIsValid(exprCollOid))
-				ereport(ERROR,
-						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg("collations are not supported by type %s",
-								format_type_be(colType))));
-		}
-
-		if (OidIsValid(exprCollOid) &&
-			exprCollOid != DEFAULT_COLLATION_OID &&
-			exprCollOid != partCollation)
-			ereport(ERROR,
-					(errcode(ERRCODE_DATATYPE_MISMATCH),
-					 errmsg("collation of partition bound value for column \"%s\" does not match partition key collation \"%s\"",
-							colName, get_collation_name(partCollation)),
-					 parser_errposition(pstate, exprLocation(value))));
-	}
-
-	/*
 	 * Coerce to the correct type.  This might cause an explicit coercion step
 	 * to be added on top of the expression, which must be evaluated before
 	 * returning the result to the caller.