Parameters of the JDBC Connection URL¶

The table Parameters of the JDBC driver and their default value lists the optional configuration parameters of the URL and their default value:

Parameters of the JDBC driver and their default value¶
Parameter of the URL	Description
autoCommit	If `true`, the invocations to the methods of the JDBC API responsible of managing transactions are ignored. I.e. the driver ignores the invocations to the methods `setAutoCommit(...)`, `commit()` and `rollback()`. This is useful to make sure that an application does not start transactions inadvertently. Even with this parameter set to true, an application can start and finish transactions by executing the statements `BEGIN`, `COMMIT` and `ROLLBACK`. If the client invokes `setAutoCommit(false)`, after executing a `COMMIT`, the driver will not start a new transaction until it has to execute another statement. If the client invokes `setAutoCommit(false)`, take into account the limits on the duration of a transaction: By default, transactions cannot last for more than 30 minutes. Once the execution of a statement finishes, the client has to execute another statement in less than 30 seconds. See more about the limits on the duration of transaction in the section Transactions in Virtual DataPort of the VQL Guide. Default value: none.
chunkSize	The results of a query can be divided into blocks (chunks), so the Server does not have to wait for the query to finish, in order to begin sending part of the results to the client. This parameter establishes the maximum number of results that a block can contain. When the Server obtains enough results to complete a block, it sends this block to the driver and continues processing the next results. In an application that uses this driver, you can either add this parameter to the connection URL and/or before executing the query, invoke the method `setFetchSize` of the class `Statement`. The value set with the `setFetchSize` method overrides the value set in the URL. Default value: `1000`
chunkTimeout	This parameter establishes the maximum time (in milliseconds) the Server waits before returning a new block to the driver. When this time is exceeded, the Server sends the current block to the driver, even if it does not contain the number of results specified in the `chunkSize` parameter. Note: if `chunkSize` and `chunkTimeout` are `0`, the Server returns all the results in a single block. If both values are different than `0`, the Server returns a chunk whenever one of these conditions happen first: The chunk is filled (`chunkSize`) Or, after a certain time of not sending any chunk to the client (`chunkTimeout`) Default value: `90000` milliseconds (90 seconds)
describeNationalCharTypesAsBasicTypes	If `true`, the driver reports the field types NCHAR, NVARCHAR, NCLOB and LONGNVARCHAR as CHAR, VARCHAR, CLOB and LONGVARCHAR respectively. Default value: `false`
i18n	This parameter establishes the internationalization (i18n) configuration of the connection with the Server. If not present, the driver assumes the i18n of the database that you are connecting to. The parameter `i18n` in the `CONTEXT` clause of the queries overrides the value of this parameter. Default value: I18N of the database that you are connecting to
identifiersUppercase	If `true`, when executing `SELECT` queries, the names of the fields are returned in uppercase. The default value is `false`. Default value: `false`
initSize	Number of connections that the driver will establish with the server during the initialization process. These connections will remain idle, ready to be used. Default value: `0`
maxActive	When the parameter `poolEnabled` is `true`, this is the maximum number of active connections that the pool can manage at the same time. If `0`, there is no limit. Default value: `30`
maxIdle	When the parameter `poolEnabled` is `true`, this is the maximum number of active connections that will remain idle in the pool without being closed. If `0`, there is no limit. Default value: `20`
password	Password used to authenticate against Virtual DataPort. When using this parameter, also provide the value of the parameter `user`. Default value: N/A
poolEnabled	Note: this parameter is deprecated and has been removed in Denodo 7.0 The parameters `initSize`, `maxActive` and `maxIdle` are also deprecated and have also been removed in Denodo 7.0. If `true`, the driver creates a pool of connections so, when a client request a connection, instead of establishing a new connection, it returns one from the this pool. This reduces the time required to obtain a connection with the Server. If this property is `false`, the driver does not create a pool of connections and ignores the properties `initSize`, `maxActive` and `maxIdle`. Default value: `false`
publishViewsAsTables	If `false`, the metadata published by the JDBC driver describes base views as TABLE elements and the derived and interface views as VIEW elements. If `true`, the metadata describes all the views as TABLE elements. Some third-party tools require the JDBC metadata to publish all the views as tables in order to recognize the associations created between views. For these applications, add this parameter to the URL with the value `true`. Default value: `false`
queryTimeout	Maximum time (in milliseconds) the driver will wait for a query to finish. After this period, it will throw an Exception. This parameter is optional. If it is not set, the query timeout has the default value (900000 milliseconds). If 0, the driver will wait indefinitely until the query finishes. This parameter sets the default timeout for all the queries. In addition, you can change the timeout for a single query by adding the parameter ‘QUERYTIMEOUT’ = ‘<value>’ to the CONTEXT clause of the query. See more about this in the section CONTEXT Clause of the Advanced VQL Guide. Default value: `900000` milliseconds (15 minutes)
reuseRegistrySocket, pingQuery and pingQueryTimeout	Parameters needed when connecting to Virtual DataPort through a load balancer. The section Connecting to Virtual DataPort Through a Load Balancer explains how to use them. Default value: None
ssl	By default, the driver tries to establish a non-SSL connection with the Server. If SSL is enabled on the Server, the connection fails and immediately, the driver tries to establish an SSL connection. If `true`, the driver only establishes SSL connections. If SSL is not enabled on the Server, the connection will fail. If `false`, the driver only establishes non-SSL connections, it does not try to establish SSL connections. If SSL is enabled on the Server, the connection will fail. Default value: None
user	User name used to authenticate against Virtual DataPort. When using this parameter, also provide the value of the parameter `password`. Default value: N/A
userAgent	Sets the user agent of the connection. The section “Setting the User Agent of an Application” of the Administration Guide explains why we recommend setting this parameter. Default value: <empty>
userGSSCredential	Java object of the class `org.ietf.jgss.GSSCredential`. Use this parameter to pass a Kerberos credential, which the driver will use to connect to Denodo. See more about this property in the section Connecting to Virtual DataPort Using Kerberos Authentication Default value: none.
wanOptimizedCalls	If `true` the driver reduces the number of remote calls it sends to the Server. In addition, when the application closes a result set, the driver only sends a cancel request to the Server if there are still pending results. If `false`, the driver always sends the cancel request. Setting this property to `true` does not provide much improvement on a Local Area Network, but it is very beneficial when working in a Wide Area Network (WAN). E.g. when the Server is on the cloud and the client application is on-premises. Default value: `false`

Autocommit

By default, the connections opened by the Denodo JDBC driver have the property “autocommit” set to true. This is the recommended value and its effect is that the queries are not performed inside a transaction.

You should not change this property to false unless you need the statements to be executed inside the same transaction. The reason is that Virtual DataPort uses a distributed transaction manager, which uses a 2-phase commit protocol. This protocol introduces some overhead over the queries. Therefore, if you set this property to false without needing it, your queries will run unnecessarily slower.

USER MANUALS

Parameters of the JDBC Connection URL¶