Write last record with the same key from batch (#12048)

Author: aavdonkin

ydb/core/formats/arrow/permutations.cpp

@@ -41,10 +41,14 @@ std::shared_ptr<arrow::UInt64Array> MakeSortPermutation(const std::vector<std::s
     }
 
     if (haveNulls) {
-        std::sort(points.begin(), points.end());
+        std::sort(points.begin(), points.end(), [](const TRawReplaceKey& a, const TRawReplaceKey& b) {
+            auto cmp = a <=> b;
+            return cmp == std::partial_ordering::equivalent ? a.GetPosition() > b.GetPosition() : cmp == std::partial_ordering::less;
+        });
     } else {
         std::sort(points.begin(), points.end(), [](const TRawReplaceKey& a, const TRawReplaceKey& b) {
-            return a.CompareNotNull(b) == std::partial_ordering::less;
+            auto cmp = a.CompareNotNull(b);
+            return cmp == std::partial_ordering::equivalent ? a.GetPosition() > b.GetPosition() : cmp == std::partial_ordering::less;
         });
     }
 

ydb/core/kqp/ut/olap/kqp_olap_ut.cpp

@@ -2443,7 +2443,7 @@ Y_UNIT_TEST_SUITE(KqpOlap) {
 //            Cout << "Wait indexation..." << Endl;
 //            Sleep(TDuration::Seconds(2));
 //        }
-        testHelper.ReadData("SELECT * FROM `/Root/ColumnTableTest` WHERE id=2", "[[2;\"test_res_2\";#;[\"val1\"]]]");
+        testHelper.ReadData("SELECT * FROM `/Root/ColumnTableTest` WHERE id=2", "[[2;\"test_res_2\";#;[\"val2\"]]]");
     }
 
     Y_UNIT_TEST(BulkUpsertUpdate) {