hotfix for Decimal.compareAt

dbms/src/Columns/ColumnDecimal.cpp

@@ -26,7 +26,7 @@ namespace ErrorCodes
 template <typename T>
 int ColumnDecimal<T>::compareAt(size_t n, size_t m, const IColumn & rhs_, int) const
 {
-    auto other = static_cast<const Self &>(rhs_);
+    auto & other = static_cast<const Self &>(rhs_);
     const T & a = data[n];
     const T & b = other.data[m];
 

dbms/tests/queries/0_stateless/00880_decimal_in_key.reference

+1000000
+1000000

dbms/tests/queries/0_stateless/00880_decimal_in_key.sql

+DROP TABLE IF EXISTS t1;
+DROP TABLE IF EXISTS t2;
+
+CREATE TABLE t1 (str String, dec Decimal64(8)) ENGINE = MergeTree ORDER BY str;
+CREATE TABLE t2 (str String, dec Decimal64(8)) ENGINE = MergeTree ORDER BY dec;
+
+INSERT INTO t1 SELECT toString(number), toDecimal64(number, 8) FROM system.numbers LIMIT 1000000;
+SELECT count() FROM t1;
+
+INSERT INTO t2 SELECT toString(number), toDecimal64(number, 8) FROM system.numbers LIMIT 1000000;
+SELECT count() FROM t2;
+
+DROP TABLE t1;
+DROP TABLE t2;