[improvement](jdbc mysql) support auto calculate the precision of timestamp/datetime (#20788)

docker/thirdparties/docker-compose/mysql/init/03-create-table.sql

@@ -289,4 +289,14 @@ CREATE TABLE `doris_test`.`auto_default_t` (
     `name` varchar(64) DEFAULT NULL,
     `dt` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
     PRIMARY KEY (`id`)
+) engine=innodb charset=utf8;
+
+create table doris_test.dt (
+  `timestamp0` timestamp(0),
+  `timestamp1` timestamp(1),
+  `timestamp2` timestamp(2),
+  `timestamp3` timestamp(3),
+  `timestamp4` timestamp(4),
+  `timestamp5` timestamp(5),
+  `timestamp6` timestamp(6)
 ) engine=innodb charset=utf8;

docker/thirdparties/docker-compose/mysql/init/04-insert.sql

@@ -1138,3 +1138,8 @@ INSERT INTO doris_test.all_types VALUES
 (203, 303, 403, 503, 603, 7.14159, 8.1415926, 9.141592, false, null, -402, 2017, -602, -902, -1102, '2012-11-02', null, '2013-10-27 08:11:18.3456712',
  -5.14145000001, -6.1400000000001, -7.140000000001, 'row3', 'line3', '09:11:09.56782346', 'text3', X'E86F6C6C6F20576F726C67', '{"name": "ChenQi", "age": 24, "city": "ChongQing"}',
  'Option2', b'101111', X'58676C6C6F', null, 'Value1');
+
+INSERT INTO doris_test.dt (`timestamp0`, `timestamp1`, `timestamp2`, `timestamp3`, `timestamp4`, `timestamp5`, `timestamp6`)
+VALUES ('2023-06-17 10:00:00', '2023-06-17 10:00:01.1', '2023-06-17 10:00:02.22', '2023-06-17 10:00:03.333', 
+        '2023-06-17 10:00:04.4444', '2023-06-17 10:00:05.55555', '2023-06-17 10:00:06.666666');
+

fe/fe-core/src/main/java/org/apache/doris/external/jdbc/JdbcMySQLClient.java

@@ -242,10 +242,11 @@ public class JdbcMySQLClient extends JdbcClient {
                     return Type.BIGINT;
                 case "BIGINT":
                     return Type.LARGEINT;
-                case "DECIMAL":
+                case "DECIMAL": {
                     int precision = fieldSchema.getColumnSize() + 1;
                     int scale = fieldSchema.getDecimalDigits();
                     return createDecimalOrStringType(precision, scale);
+                }
                 case "DOUBLE":
                     // As of MySQL 8.0.17, the UNSIGNED attribute is deprecated
                     // for columns of type FLOAT, DOUBLE, and DECIMAL (and any synonyms)
@@ -278,19 +279,28 @@ public class JdbcMySQLClient extends JdbcClient {
                 return ScalarType.createDateV2Type();
             case "TIMESTAMP":
             case "DATETIME":
-            case "DATETIMEV2": // for jdbc catalog connecting Doris database
+            // for jdbc catalog connecting Doris database
+            case "DATETIMEV2": {
                 // mysql can support microsecond
-                // todo(gaoxin): Get real precision of DATETIMEV2
-                return ScalarType.createDatetimeV2Type(JDBC_DATETIME_SCALE);
+                // use columnSize to calculate the precision of timestamp/datetime
+                int columnSize = fieldSchema.getColumnSize();
+                int scale = columnSize > 19 ? columnSize - 20 : 0;
+                if (scale > 6) {
+                    scale = 6;
+                }
+                return ScalarType.createDatetimeV2Type(scale);
+            }
             case "FLOAT":
                 return Type.FLOAT;
             case "DOUBLE":
                 return Type.DOUBLE;
             case "DECIMAL":
-            case "DECIMALV3": // for jdbc catalog connecting Doris database
+            // for jdbc catalog connecting Doris database
+            case "DECIMALV3": {
                 int precision = fieldSchema.getColumnSize();
                 int scale = fieldSchema.getDecimalDigits();
                 return createDecimalOrStringType(precision, scale);
+            }
             case "CHAR":
                 ScalarType charType = ScalarType.createType(PrimitiveType.CHAR);
                 charType.setLength(fieldSchema.columnSize);

fe/fe-core/src/main/java/org/apache/doris/external/jdbc/JdbcPostgreSQLClient.java

@@ -65,14 +65,14 @@ public class JdbcPostgreSQLClient extends JdbcClient {
                 charType.setLength(fieldSchema.columnSize);
                 return charType;
             case "timestamp":
-            case "timestamptz":
+            case "timestamptz": {
                 // postgres can support microsecond
                 int scale = fieldSchema.getDecimalDigits();
-                if (scale < 6) {
-                    return ScalarType.createDatetimeV2Type(scale);
-                } else {
-                    return ScalarType.createDatetimeV2Type(JDBC_DATETIME_SCALE);
+                if (scale > 6) {
+                    scale = 6;
                 }
+                return ScalarType.createDatetimeV2Type(scale);
+            }
             case "date":
                 return ScalarType.createDateV2Type();
             case "bool":

regression-test/data/jdbc_catalog_p0/test_mysql_jdbc_catalog.out

@@ -249,6 +249,9 @@ VIEW_TABLE_USAGE
 -- !auto_default_t --
 0
 
+-- !dt --
+2023-06-17T10:00	2023-06-17T10:00:01.100	2023-06-17T10:00:02.220	2023-06-17T10:00:03.333	2023-06-17T10:00:04.444400	2023-06-17T10:00:05.555550	2023-06-17T10:00:06.666666
+
 -- !test_insert1 --
 doris1	18
 

regression-test/suites/jdbc_catalog_p0/test_mysql_jdbc_catalog.groovy

@@ -49,6 +49,7 @@ suite("test_mysql_jdbc_catalog", "p0") {
         String test_insert = "test_insert";
         String test_insert2 = "test_insert2";
         String auto_default_t = "auto_default_t";
+        String dt = "dt";
 
         sql """drop catalog if exists ${catalog_name} """
 
@@ -101,6 +102,7 @@ suite("test_mysql_jdbc_catalog", "p0") {
         order_qt_ex_tb20  """ select * from ${ex_tb20} order by decimal_normal; """
         order_qt_information_schema """ show tables from information_schema; """
         order_qt_auto_default_t """insert into ${auto_default_t}(name) values('a'); """
+        order_qt_dt """select * from ${dt}; """
 
         // test insert
         String uuid1 = UUID.randomUUID().toString();