[BugFix](sort) use correct agg function when using 2 phase sort for agg table (#16185)

be/src/olap/tablet_schema.h

@@ -77,6 +77,8 @@ public:
     int frac() const { return _frac; }
     inline bool visible() const { return _visible; }
 
+    void set_aggregation_method(FieldAggregationMethod agg) { _aggregation = agg; }
+
     /**
      * Add a sub column.
      */

be/src/vec/exec/scan/new_olap_scanner.cpp

@@ -102,6 +102,8 @@ Status NewOlapScanner::prepare(const TPaloScanRange& scan_range,
                 rowid_column.set_has_default_value(true);
                 // fake unique id
                 rowid_column.set_unique_id(INT32_MAX);
+                rowid_column.set_aggregation_method(
+                        FieldAggregationMethod::OLAP_FIELD_AGGREGATION_REPLACE);
                 rowid_column.set_type(FieldType::OLAP_FIELD_TYPE_STRING);
                 _tablet_schema->append_column(rowid_column);
             }

regression-test/data/query_p0/sort/sort.out

@@ -10,3 +10,5 @@
 -- !sort_string_on_fe --
 true
 
+-- !sql --
+

regression-test/suites/query_p0/sort/sort.groovy

@@ -23,4 +23,22 @@ suite("sort") {
     qt_sort_string_single_column """ select * from ( select '汇总' as a union all select '2022-01-01' as a ) a order by 1 """
     qt_sort_string_multiple_columns """ select * from ( select '汇总' as a,1 as b union all select '2022-01-01' as a,1 as b ) a order by 1,2 """
     qt_sort_string_on_fe """ select '汇总' > '2022-01-01' """
+
+    sql """CREATE TABLE IF NOT EXISTS Test2PhaseSortWhenAggTable
+    (`l1` VARCHAR(20) NOT NULL, `l2` VARCHAR(20) NOT NULL, `id` INT REPLACE NOT NULL, `maximum` INT MAX DEFAULT "0" )
+    ENGINE=olap AGGREGATE KEY(`l1`, `l2`) PARTITION BY LIST(`l1`, `l2`) ( PARTITION `p1` VALUES IN (("a", "a"), ("b", "b"), ("c", "c")),
+    PARTITION `p2` VALUES IN (("d", "d"), ("e", "e"), ("f", "f")), PARTITION `p3` VALUES IN (("g", "g"), ("h", "h"), ("i", "i")) ) DISTRIBUTED BY HASH(`l1`) BUCKETS 2 PROPERTIES ( "replication_num" = "1" )"""
+
+    sql """insert into Test2PhaseSortWhenAggTable values ("a", "a", 1, 1), ("b", "b", 3, 2), ("c", "c", 3, 3), ("d", "d", 4, 4), ("e", "e", 5, 5), ("f", "f", 6, 6), ("g", "g", 7, 7), ("h", "h", 8, 8), ("i", "i", 9, 9)"""
+
+    qt_sql """
+    SELECT /*+ SET_VAR(query_timeout = 600) */ ref_0.`l1` AS c0,
+                                           bitmap_empty() AS c1,
+                                           ref_0.`l1` AS c2
+    FROM Test2PhaseSortWhenAggTable AS ref_0
+    WHERE ref_0.`l2` IS NOT NULL
+    ORDER BY ref_0.`l1` DESC
+    LIMIT 110
+    OFFSET 130
+    """
 }