Attributes of the VDBServerManagementInfo MBean¶

The VDBServerManagementInfo MBean has these attributes:

• ActiveConnections: number of clients connected currently. This figure includes any type of clients: Administration Tools, JDBC clients, ODBC clients, published Web services, etc.

• ActiveRequests: number of queries that are currently running.

• ActiveTransactions: number of active transactions.

• InstanceName: if the attribute Master is false, this attribute contains the name of the instance.

• Master: true if the Server is running standalone or is the Master instance of a group of instances of the same installation. See more information about this on the section Launching Several Virtual DataPort Instances of the Same Installation. false otherwise.

• ServerName: logical name URI of this Virtual DataPort server.

• ServerUpdate: name of the update installed on this server. For example: “8.0” (for 8.0 GA) or “7.0 20190903”.

• SingleUserModeConnection: id of the connection that has switched the Server to single user mode. This occurs if a client application executed the command ENTER SINGLE USER MODE but not EXIT SINGLE USER  MODE; or if it is running a statement that temporarily switches the server to single user mode (e.g. create a user, create a database, etc.)

  The section Automatic Single User Mode lists what operations block the entire Server.

  The attribute is empty if the server is not in single user mode.

• TotalConnectionFailures: number of failed connections. For example, clients that tried to connect to the Server with invalid credentials.

• TotalConnections: number of connections established with the Server, since it was started.

• TotalTransactions: number of transactions started since the Server was started.

• WaitingRequests: number of requests that are waiting to be executed. These requests are waiting because the Server has surpassed the “Maximum concurrent requests” threshold.

Operations of the VDBServerManagementInfo MBean¶

The VDBServerManagementInfo MBean has these operations:

• cancelRequest( <request id:integer> ): cancels the request with the identifier “request id”.

  To obtain the id of a request you want to cancel, invoke the getActiveRequestList operation (see below), which will return information about the running requests, including their id.

• cancelCacheProcess( <cache process id:long> ): cancels the cache process with the identifier “cache process id”.

  To obtain the identifier of a cache process open to the DatabaseCache MBean of the database where the cache process is running and invoke the operation getActiveRefreshCacheProcesses. This operation returns information about the cache processes running. Look for the “Identifier” attribute of the process you want to stop and use it as parameter of this operation. See more about the getActiveRefreshCacheProcesses operation in the section DatabaseCache MBean.

  When you invoke this operation, the cache process is cancelled, but the query continues until it finishes.

• closeConnectionById( <connection id : long> ): closes the connection with the identifier “connection id”.

  To obtain the identifier of a connection, invoke the operation getSessions(...) described below, which returns information about all the opened connections. In the result, look for the attribute “ConnectionId”.

• closeConnectionsByIP( <IP address : String> ): closes all the connections opened from an IP address. This operation returns these fields:

  • ClosedConnectionIds: identifiers of the connections successfully closed.

  • FailedClosedConnectionIds: identifiers of the connections unsuccessfully closed.

• closeConnectionsByUser( <user name : String> ): closes all the connections opened by a user. This operation returns these fields:

  • ClosedConnectionIds: identifiers of the connections successfully closed.

  • FailedClosedConnectionIds: identifiers of the connections unsuccessfully closed.

• getActiveRequestList( <max requests:integer>, <database name:text): returns the list of the queries sent to the database <database name>. This list contains:

  • The requests that are currently being executed.

  • The requests that are queued. A request is queued when the “Maximum concurrent requests” limit has been reached. See more about this limit in the section Limiting the Number of Concurrent Requests.

    When you cancel a request that has been queued, the request is not immediately canceled. Instead, it is canceled just when the Execution Engine is ready to execute this query and takes it out of the list of queued queries. Therefore, this operation returns all the requests that are queued, even if they already have been canceled.

  If you want to cancel a query, execute this operation to get the value of the attribute Identifier of the query you want to cancel. Then invoke the operation cancelRequest(...) and pass this value to it.

  If the input parameter <database name> is empty, this operation returns all the requests sent to all the databases.

  For each query, the operation returns the attribute Queued, among others. This attribute is true when the limit of maximum number of concurrent queries has been reached.

  See more about this limit and how to increase it in the section Limiting the Number of Concurrent Requests.

• getRequestById ( <request id : number> ): returns information about a specific request that is currently running or waiting to be executed. If the request has finished, you will get an error.

• getSessions( <database name : text> ): returns details about the sessions opened by clients to the Virtual DataPort server.

  If you do not provide a database name, it returns information about all the sessions. If you provide a name, it returns information about the sessions established with that database but not the others.

  This operation does not return information about connections opened by JMX clients.

  This procedure only returns information about connections opened by JMS clients during the time they are executing a query.

  This operation returns the following fields for each opened connection:

  • AccessInterface: type of client connected to the Server. Possible values of the attribute “access interface” lists the possible values of this attribute.

  • AdminUser: true if the user is an administrator user or it has the role serveradmin. false otherwise.

  • ClientIP: IP address of the client. In case of Data Catalog, Design Studio and Web services this is the IP address of the final client. I.e. the one that sends the HTTP request.

  • ConnectionId: unique identifier of the connection.

  • ConnectionStartTime: instant when the connection was opened.

  • DatabaseName: database that the client application is connected to.

  • JMSQueueName (only for JMS connections): name of the JMS queue where the query is being sent from.

  • IntermediateClientIP (only for Data Catalog, Design Studio, SOAP, REST and the global RESTful Web service): IP address where the service is running.

    If the service has been deployed in the Web container embedded in Denodo, this will be the same IP of the Virtual DataPort server. Otherwise, it is the IP address of the JEE container where the service is deployed.

  • LastExecutedQuery: last query executed by the client.

  • LastExecutedQueryEndTime: instant when the last query finished.

  • Login: user name of the client.

  • QueryRunning: query that the client is executing right now and that has not finished yet. Empty, if there is no active query.

  • QueryRunningId: unique identifier of the query that the client is executing right now. Empty, if there is no active query.

  • QueryRunningQueued: true if the client has executed a query but the query is waiting because the Server has reached the “Max concurrent requests” limit. See more about this limit and how to increase it in the section Limiting the Number of Concurrent Requests.

  • SessionId: unique identifier of the session.

  • SessionStartTime: instant when the session was opened.

  • SessionStatus: true if the session is active. False otherwise.

  • SingleUserMode: true if this session has switched one or more databases, or the entire Server to single user mode.

  • SingleUserModeDatabases: list of databases that have been switched to “single user mode”. If empty, it means that the entire Server was switched to single user mode.

  • UserAgent: name of the application that opens the connection. Setting the user agent in the application is useful to know which application opens each connection. The section Setting the User Agent of an Application explains how to set this.

  • UserAuthenticationType: type of authentication used by the client. The values can be “LOCAL”, “LDAP” or “KERBEROS”.

  • WebServiceName (only for connections opened by SOAP and REST web services published by Denodo): name of the web service. For other types of clients, this is an empty string.

Notifications of the VDBServerManagementInfo MBean¶

The VDBServerManagementInfo MBean provides these notifications:

• loginOk: when a client logs in correctly into the Virtual DataPort server.

• loginFailure: when a client fails to connect. For example, because the password provided is not correct or the user does not have enough privileges to connect to the database.

• logout: when a client logs out.

• openSession: when a client opens a session.

• closeSession: when a client closes a session.

All of these notifications provide this information:

• AccessInterface: the table Possible values of the attribute “access interface” lists the possible values of this attribute.

• ClientIP

• IntermediateClientIP

• ConnectionId

• ConnectionStartTime

• ConnectionEndTime

• SessionId

• SessionStartTime

• SessionEndTime

• Login

• DatabaseName

• JMSQueueName

• WebServiceName

• UserAgent

The meaning of these fields is explained in the previous section.

Attributes of the MemoryManagementInfo MBean¶

The MemoryManagementInfo MBean has these attributes:

• TotalMemory: total amount of memory used by the Server.

• MaxMemory: maximum amount of memory that the Server will attempt to use.

Operations of the MemoryManagementInfo MBean¶

The MemoryManagementInfo MBean has this operation:

• gc(): this operation requests the Java Virtual Machine (JVM) that executes the Virtual DataPort server, to run the garbage collector of the JVM. This request may be ignored by the JVM.