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This topic explains how to configure LabKey Server to retrieve and display data from an Oracle database as an external data source. This topic assumes you have reviewed the general guidance here and provides specific parameters and details for this database type.

Oracle JDBC Driver

LabKey supports Oracle versions 10g through 23c and requires the Oracle JDBC driver to connect to Oracle databases. The driver is included with all Premium Edition distributions.

Configure the Oracle Data Source

The new external data source must have a unique JNDI name that you will use in naming the properties you will define. In the example on this page, we use "externalOracleDataSource", which will appear to users defining external schemas as "externalOracle". If you have more than one external data source, give each a unique name with the DataSource suffix ("firstExternalOracleDataSource", "secondExternalOracleDataSource", etc.). Learn more here.

In the <LABKEY_HOME>/config/ file, add a new section with the name of the datasource and the parameters you want to define. Provide your own <SERVER:PORT>, <SERVICE>, <DB_USERNAME>, and <DB_PASSWORD> where indicated:

context.resources.jdbc.externalOracleDataSource.validationQuery=SELECT 1 FROM dual

There are additional properties you can set, as shown in the template for the main "labkeyDataSource" in the file.


Use this as the driverClassName:



The url property for Oracle takes this form, including the name of the database at the end:


Note: Connecting via SID URL is not recommended by Oracle. Refer to Oracle FAQs: JDBC for URL syntax. If you include the optional username/password portion of the JDBC URL, you must still include the username and password attributes for the data source.


Use "SELECT 1 FROM dual" as the validation query for Oracle:


The error raised in case of a syntax error in this statement might be similar to:

Caused by: java.sql.SQLSyntaxErrorException: ORA-00923: FROM keyword not found where expected

Define a New External Schema

To define a new schema from this data source see Set Up an External Schema.


Recovery File Size

Below are steps to take if you see an error on the Oracle console (or see an error in Event Viewer -> Windows Logs -> Application) that says one of the following:
  • "ORA-19809: limit exceeded for recovery files"
  • "ORA-03113: end-of-file on communication channel"
  • "ORA-27101: shared memory realm does not exist"
  1. Update the RMAN value for "db_recovery_file_dest_size" to be a bit higher (i.e. from 16G to 20G).
  2. Restart your VM/machine.
  3. Restart Oracle.

Number (Decimal/Double) Data Truncates to Integer

If you have a column of type NUMBER and its value is being shown as an integer instead of a decimal, the source of the problem may be a bug in the Oracle JDBC driver. More information can be found here:

  1. Set the following Java system property in the arguments used to launch the JVM:

Open Cursor Limits

Oracle's thin JDBC driver has a long-standing bug that causes it to leak cursors. This presents a problem because LabKey uses a connection pooling approach.

LabKey has worked around this problem by estimating the number of cursors that are still available for the connection and discarding it when it approaches the limit. To accomplish this, the server issues the following query to Oracle:


If the query cannot be executed, typically because the account doesn't have permission, LabKey will log a warning indicating it was unable to determine the max open cursors, and assume that Oracle is configured to use its default limit, 50. If Oracle's limit is set to 50 or higher, the warning can be safely ignored.

To avoid the warning message, grant the account permission to run the query against V$PARAMETER.

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