The MySQL-type data source is using a DolphinDB-type driver.

[njnu-seafish]

ds version: 3.3.1-release

1, Create a SQL task using MySQL-type datasource

2, Run this task, The following error log will appear.

2026-03-05 19:04:51.606 INFO - 🐬 Execute Task Instance
2026-03-05 19:04:51.606 INFO - Full sql parameters: SqlParameters{type='MYSQL', datasource=3, sql=' select 2 as alarmflag;', sqlType=0, sendEmail=false, displayRows=25, limit=0, showType='null', connParams='null', groupId='0', title='null', preStatements=[], postStatements=[]}
2026-03-05 19:04:51.606 INFO - sql type : MYSQL, datasource : 3, sql : select 2 as alarmflag; , localParams : [Property(prop=alarmflag, direct=OUT, type=LONG, value=)],showType : null,connParams : null,varPool : [] ,query max result limit 0
2026-03-05 19:04:51.607 INFO - after replace sql , preparing : select 2 as alarmflag
2026-03-05 19:04:51.607 INFO - Sql Params are replaced sql , parameters:
2026-03-05 19:04:51.608 WARN - Connect strings must start with jdbc:snowflake://
2026-03-05 19:04:51.657 ERROR - execute sql error: Create adhoc connection error
2026-03-05 19:04:51.658 ERROR - sql task error
java.sql.SQLException: Create adhoc connection error
at org.apache.dolphinscheduler.plugin.datasource.api.client.BaseAdHocDataSourceClient.getConnection(BaseAdHocDataSourceClient.java:43)
at org.apache.dolphinscheduler.plugin.datasource.api.plugin.DataSourceClientProvider.getAdHocConnection(DataSourceClientProvider.java:95)
at org.apache.dolphinscheduler.plugin.task.sql.SqlTask.executeFuncAndSql(SqlTask.java:181)
at org.apache.dolphinscheduler.plugin.task.sql.SqlTask.handle(SqlTask.java:153)
at org.apache.dolphinscheduler.server.worker.executor.PhysicalTaskExecutor.doTriggerTaskPlugin(PhysicalTaskExecutor.java:75)
at org.apache.dolphinscheduler.task.executor.AbstractTaskExecutor.start(AbstractTaskExecutor.java:81)
at org.apache.dolphinscheduler.task.executor.worker.TaskExecutorWorker.start(TaskExecutorWorker.java:65)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:750)
Caused by: java.sql.SQLException: url is not valid
at com.dolphindb.jdbc.Driver.parseProp(Driver.java:71)
at com.dolphindb.jdbc.Driver.createConnection(Driver.java:125)
at com.dolphindb.jdbc.Driver.connect(Driver.java:32)
at java.sql.DriverManager.getConnection(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:208)
at org.apache.dolphinscheduler.plugin.datasource.mysql.param.MySQLDataSourceProcessor.getConnection(MySQLDataSourceProcessor.java:143)
at org.apache.dolphinscheduler.plugin.datasource.api.client.BaseAdHocDataSourceClient.getConnection(BaseAdHocDataSourceClient.java:41)
... 11 common frames omitted
2026-03-05 19:04:51.658 ERROR - PhysicalTaskExecutor{id=1191, name=count, stat=RUNNING} execute failed
org.apache.dolphinscheduler.plugin.task.api.TaskException: Execute sql task failed
at org.apache.dolphinscheduler.plugin.task.sql.SqlTask.handle(SqlTask.java:160)
at org.apache.dolphinscheduler.server.worker.executor.PhysicalTaskExecutor.doTriggerTaskPlugin(PhysicalTaskExecutor.java:75)
at org.apache.dolphinscheduler.task.executor.AbstractTaskExecutor.start(AbstractTaskExecutor.java:81)
at org.apache.dolphinscheduler.task.executor.worker.TaskExecutorWorker.start(TaskExecutorWorker.java:65)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:750)
Caused by: java.sql.SQLException: Create adhoc connection error
at org.apache.dolphinscheduler.plugin.datasource.api.client.BaseAdHocDataSourceClient.getConnection(BaseAdHocDataSourceClient.java:43)
at org.apache.dolphinscheduler.plugin.datasource.api.plugin.DataSourceClientProvider.getAdHocConnection(DataSourceClientProvider.java:95)
at org.apache.dolphinscheduler.plugin.task.sql.SqlTask.executeFuncAndSql(SqlTask.java:181)
at org.apache.dolphinscheduler.plugin.task.sql.SqlTask.handle(SqlTask.java:153)
... 8 common frames omitted
Caused by: java.sql.SQLException: url is not valid
at com.dolphindb.jdbc.Driver.parseProp(Driver.java:71)
at com.dolphindb.jdbc.Driver.createConnection(Driver.java:125)
at com.dolphindb.jdbc.Driver.connect(Driver.java:32)
at java.sql.DriverManager.getConnection(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:208)
at org.apache.dolphinscheduler.plugin.datasource.mysql.param.MySQLDataSourceProcessor.getConnection(MySQLDataSourceProcessor.java:143)
at org.apache.dolphinscheduler.plugin.datasource.api.client.BaseAdHocDataSourceClient.getConnection(BaseAdHocDataSourceClient.java:41)
... 11 common frames omitted
2026-03-05 19:04:51.845 INFO - 🐬 Finalize Task Instance
2026-03-05 19:04:51.846 INFO - Clearing task execution path: /data01/dolphinscheduler/exec/process/1191
2026-03-05 19:04:51.847 INFO - Successfully cleared task execution path: /data01/dolphinscheduler/exec/process/1191
2026-03-05 19:04:51.847 INFO - FINALIZE_SESSION

3，Find the jar about com.dolphindb.jdbc.Driver

$ grep -ir "dolphindb" ./
...
./conf/plugins_config:dolphinscheduler-datasource-dolphindb
Binary file ./plugins/datasource-plugins/dolphinscheduler-datasource-dolphindb-3.3.2-SNAPSHOT-shade.jar matches
Binary file ./plugins/task-plugins/dolphinscheduler-task-aliyunserverlessspark-3.3.2-SNAPSHOT-shade.jar matches
...

4, Remove the jar, the restart the worker service

[root@8f1ccmith6g2a10][/usr/local/dolphinscheduler]
$ ll ./plugins/datasource-plugins/ | grep -i dolphinscheduler-datasource-dolphindb
-rw-r--r-- 1 dolphinscheduler dolphinscheduler 1.4M Feb 18 2022 dolphinscheduler-datasource-dolphindb-3.3.2-SNAPSHOT-shade.jar_bak0305

$ ll ./plugins/task-plugins/ | grep -i dolphinscheduler-task-aliyunserverlessspark
-rw-r--r-- 1 dolphinscheduler dolphinscheduler 265M Feb 18 2022 dolphinscheduler-task-aliyunserverlessspark-3.3.2-SNAPSHOT-shade.jar_bak0305

systemctl restart dolphinscheduler-worker

5, Run this task again, it is ok

2026-03-05 19:32:40.766 INFO - 🐬 Execute Task Instance
2026-03-05 19:32:40.766 INFO - Full sql parameters: SqlParameters{type='MYSQL', datasource=3, sql=' select 2 as alarmflag;', sqlType=0, sendEmail=false, displayRows=25, limit=0, showType='null', connParams='null', groupId='0', title='null', preStatements=[], postStatements=[]}
2026-03-05 19:32:40.766 INFO - sql type : MYSQL, datasource : 3, sql : select 2 as alarmflag; , localParams : [Property(prop=alarmflag, direct=OUT, type=LONG, value=)],showType : null,connParams : null,varPool : [] ,query max result limit 0
2026-03-05 19:32:40.766 INFO - after replace sql , preparing : select 2 as alarmflag
2026-03-05 19:32:40.766 INFO - Sql Params are replaced sql , parameters:
2026-03-05 19:32:40.767 WARN - Connect strings must start with jdbc:snowflake://
2026-03-05 19:32:40.791 INFO - prepare statement replace sql : select 2 as alarmflag, sql parameters : {}
2026-03-05 19:32:40.791 INFO - main statement execute query, for sql: select 2 as alarmflag
2026-03-05 19:32:40.792 INFO - display sql result 1 rows as follows:
2026-03-05 19:32:40.793 INFO - row 1 : {"alarmflag":2}
2026-03-05 19:32:41.114 INFO - 🐬 Finalize Task Instance
2026-03-05 19:32:41.117 INFO - Clearing task execution path: /data01/dolphinscheduler/exec/process/1209
2026-03-05 19:32:41.117 INFO - Successfully cleared task execution path: /data01/dolphinscheduler/exec/process/1209
2026-03-05 19:32:41.117 INFO - FINALIZE_SESSION

6, Change the datasource with error password, run again

2026-03-05 20:49:52.302 INFO - 🐬 Execute Task Instance
2026-03-05 20:49:52.303 INFO - Full sql parameters: SqlParameters{type='MYSQL', datasource=3, sql=' select 2 as alarmflag;', sqlType=0, sendEmail=false, displayRows=25, limit=0, showType='null', connParams='null', groupId='0', title='null', preStatements=[], postStatements=[]}
2026-03-05 20:49:52.303 INFO - sql type : MYSQL, datasource : 3, sql : select 2 as alarmflag; , localParams : [Property(prop=alarmflag, direct=OUT, type=LONG, value=)],showType : null,connParams : null,varPool : [] ,query max result limit 0
2026-03-05 20:49:52.303 INFO - after replace sql , preparing : select 2 as alarmflag
2026-03-05 20:49:52.304 INFO - Sql Params are replaced sql , parameters:
2026-03-05 20:49:52.304 WARN - Connect strings must start with jdbc:snowflake://
2026-03-05 20:49:52.333 ERROR - execute sql error: Create adhoc connection error
2026-03-05 20:49:52.334 ERROR - sql task error
java.sql.SQLException: Create adhoc connection error
at org.apache.dolphinscheduler.plugin.datasource.api.client.BaseAdHocDataSourceClient.getConnection(BaseAdHocDataSourceClient.java:43)
at org.apache.dolphinscheduler.plugin.datasource.api.plugin.DataSourceClientProvider.getAdHocConnection(DataSourceClientProvider.java:95)
at org.apache.dolphinscheduler.plugin.task.sql.SqlTask.executeFuncAndSql(SqlTask.java:181)
at org.apache.dolphinscheduler.plugin.task.sql.SqlTask.handle(SqlTask.java:153)
at org.apache.dolphinscheduler.server.worker.executor.PhysicalTaskExecutor.doTriggerTaskPlugin(PhysicalTaskExecutor.java:75)
at org.apache.dolphinscheduler.task.executor.AbstractTaskExecutor.start(AbstractTaskExecutor.java:81)
at org.apache.dolphinscheduler.task.executor.worker.TaskExecutorWorker.start(TaskExecutorWorker.java:65)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:750)
Caused by: java.sql.SQLException: Access denied for user 'dolphinscheduler'@'8f1ccmith6g2a10' (using password: YES)
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:130)
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)
at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:825)
at com.mysql.cj.jdbc.ConnectionImpl.(ConnectionImpl.java:446)
at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:239)
at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:188)
at java.sql.DriverManager.getConnection(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:208)
at org.apache.dolphinscheduler.plugin.datasource.mysql.param.MySQLDataSourceProcessor.getConnection(MySQLDataSourceProcessor.java:143)
at org.apache.dolphinscheduler.plugin.datasource.api.client.BaseAdHocDataSourceClient.getConnection(BaseAdHocDataSourceClient.java:41)
... 11 common frames omitted
2026-03-05 20:49:52.334 ERROR - PhysicalTaskExecutor{id=1260, name=count, stat=RUNNING} execute failed
org.apache.dolphinscheduler.plugin.task.api.TaskException: Execute sql task failed
at org.apache.dolphinscheduler.plugin.task.sql.SqlTask.handle(SqlTask.java:160)
at org.apache.dolphinscheduler.server.worker.executor.PhysicalTaskExecutor.doTriggerTaskPlugin(PhysicalTaskExecutor.java:75)
at org.apache.dolphinscheduler.task.executor.AbstractTaskExecutor.start(AbstractTaskExecutor.java:81)
at org.apache.dolphinscheduler.task.executor.worker.TaskExecutorWorker.start(TaskExecutorWorker.java:65)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:750)
Caused by: java.sql.SQLException: Create adhoc connection error
at org.apache.dolphinscheduler.plugin.datasource.api.client.BaseAdHocDataSourceClient.getConnection(BaseAdHocDataSourceClient.java:43)
at org.apache.dolphinscheduler.plugin.datasource.api.plugin.DataSourceClientProvider.getAdHocConnection(DataSourceClientProvider.java:95)
at org.apache.dolphinscheduler.plugin.task.sql.SqlTask.executeFuncAndSql(SqlTask.java:181)
at org.apache.dolphinscheduler.plugin.task.sql.SqlTask.handle(SqlTask.java:153)
... 8 common frames omitted
Caused by: java.sql.SQLException: Access denied for user 'dolphinscheduler'@'8f1ccmith6g2a10' (using password: YES)
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:130)
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)
at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:825)
at com.mysql.cj.jdbc.ConnectionImpl.(ConnectionImpl.java:446)
at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:239)
at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:188)
at java.sql.DriverManager.getConnection(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:208)
at org.apache.dolphinscheduler.plugin.datasource.mysql.param.MySQLDataSourceProcessor.getConnection(MySQLDataSourceProcessor.java:143)
at org.apache.dolphinscheduler.plugin.datasource.api.client.BaseAdHocDataSourceClient.getConnection(BaseAdHocDataSourceClient.java:41)
... 11 common frames omitted
2026-03-05 20:49:52.643 INFO - 🐬 Finalize Task Instance
2026-03-05 20:49:52.645 INFO - Clearing task execution path: /data01/dolphinscheduler/exec/process/1260
2026-03-05 20:49:52.645 INFO - Successfully cleared task execution path: /data01/dolphinscheduler/exec/process/1260
2026-03-05 20:49:52.645 INFO - FINALIZE_SESSION

[njnu-seafish]

Issues related to this include:
#17464
#17891

[njnu-seafish]

In the DolphinScheduler runtime environment (Worker nodes), both the DolphinDB JDBC driver JAR and the MySQL JDBC driver JAR are present; however, the class loading mechanism causes the DolphinDB driver to be registered first.

After removing the DolphinDB JDBC driver JAR, the program use the MySQL JDBC driver.

[ruanwenjun]

This is because we currently haven't specified a driver when creating the connection.
JDBC itself determines which driver to use based on the URL, and the jdbc url you're using is not officially supported by MySQL.