Gracefully shutting down DAS (via Management Console) causes to shutdown the connected MySQL server as well. Originally reported in product-das repo.

Affected Product Version:

• since v1.0.1

Environment:

• DAS 3.1.0 (with ML datasource "WSO2ML_DB" pointed to MySQL)
• MySQL v5.7.9 or higher

Steps to reproduce:

1. Point ML datasource "WSO2ML_DB" to MySQL
   • File: <DAS_HOME>/repository/conf/datasources/ml-datasources.xml
   • DB user: root
2. Start DAS
3. Go to Management Console and do graceful shutdown
4. After DAS shutdown, you can notice that MySQL server has been shutdown as well

Cause:
In the ML REST API webapp (api.war), org.wso2.carbon.ml.rest.api.handler.ShutdownListener class is configures as a listener [1] and ShutdownListener.contextDestroyed [2] method gets called on the webapp undeploy event. Inside that, DatabaseService.shutdown method is invoked, which ultimately executes the SHUTDOWN query [3].

[1] https://github.com/wso2/carbon-ml/blob/v1.2.2/components/ml/org.wso2.carbon.ml.rest.api/src/main/webapp/WEB-INF/web.xml#L40
[2] https://github.com/wso2/carbon-ml/blob/v1.2.2/components/ml/org.wso2.carbon.ml.rest.api/src/main/java/org/wso2/carbon/ml/rest/api/handler/ShutdownListener.java#L37
[3] https://github.com/wso2/carbon-ml/blob/v1.2.2/components/ml/org.wso2.carbon.ml.database/src/main/java/org/wso2/carbon/ml/database/internal/MLDatabaseService.java#L2724

Downloaded the carbon.ml.core 1.0.2 source code from github and modified the algorithm linear regression and replaced the org.wso2.carbon.ml.core-1.0.2.jar in to the build location \wso2ml-1.0.0\repository\components\plugins.
But while running the wso2server.bat with the error message :
Error occuring while deploying webapp "E:\wso2ml-1.0.0\repository\deployment\server\webapps\api.war"

Description:
<DAS_HOME>/dbscripts/ml/ directory does not contains a SQL script intended for MS SQL Server (mssql.sql) for ML DB tables.

A colleague of mine noticed that there are two public methods getAllDatasetVersions() and getAllVersionsetsOfDataset() in org.wso2.carbon.ml.core.impl.MLDatasetProcessor that appear to be doing the exact same thing.