Fix decimal bug in orc load (#2984)

be/src/exec/orc_scanner.cpp

@@ -246,9 +246,21 @@ Status ORCScanner::get_next(Tuple* tuple, MemPool* tuple_pool, bool* eof) {
                             } else {
                                 decimal_str = ((orc::Decimal128VectorBatch*) cvb)->values[_current_line_of_group].toString();
                             }
-                            //Orc api will fill in 0 at the end, so size must greater than scale. But 0 is not fill.
-                            std::string v = decimal_str == "0" ? 
-                                "0" : (decimal_str.substr(0, decimal_str.size() - scale) + "." + decimal_str.substr(decimal_str.size() - scale));
+
+                            std::string v;
+                            if (decimal_str.size() <= scale) {
+                                // decimal(5,2) : the integer of 0.01 is 1, so we should fill 0 befor integer
+                                v = "0.";
+                                int fill_zero = scale - decimal_str.size();
+                                while (fill_zero--) {
+                                    v += "0";
+                                }
+                                v += decimal_str;
+                            } else {
+                                //Orc api will fill in 0 at the end, so size must greater than scale
+                                v = decimal_str.substr(0, decimal_str.size() - scale) + "." + decimal_str.substr(decimal_str.size() - scale);
+                            }
+
                             str_slot->ptr = reinterpret_cast<char*>(tuple_pool->allocate(v.size()));
                             memcpy(str_slot->ptr, v.c_str(), v.size());
                             str_slot->len = v.size();

be/test/exec/orc_scanner_test.cpp

@@ -746,7 +746,7 @@ TEST_F(OrcScannerTest, normal3) {
     bool eof = false;
     ASSERT_TRUE(scanner.get_next(tuple, &tuple_pool, &eof).ok());
     ASSERT_EQ(Tuple::to_string(tuple, *_desc_tbl->get_tuple_descriptor(1)),
-                "(0.123456789 1.12 -1.1234500000 0.12345 0 1 2020-01-14 22:12:19)");
+                "(0.123456789 1.12 -1.1234500000 0.12345 0.000 1 2020-01-14 22:12:19)");
     scanner.close();
 }