Configuring Looker to use Unpackaged JDBC drivers
For some of Looker's supported dialects, the JDBC driver cannot be packaged in the Looker JAR file for licensing-related reasons. In these cases, you must install the JDBC driver on your Looker server, then configure Looker to register the unpackaged driver as described on this page.
All dialects with a value of "No" under "Supported?" require unpackaged JDBC driver installations:
Dialect | Supported? |
---|---|
Actian Avalanche | No |
Amazon Athena | Yes |
Amazon Aurora MySQL | Yes |
Amazon Redshift | Yes |
Apache Druid | Yes |
Apache Druid 0.13+ | Yes |
Apache Druid 0.18+ | Yes |
Apache Hive 2.3+ | Yes |
Apache Hive 3.1.2+ | Yes |
Apache Spark 3+ | Yes |
ClickHouse | Yes |
Cloudera Impala 3.1+ | Yes |
Cloudera Impala 3.1+ with Native Driver | No |
Cloudera Impala with Native Driver | No |
DataVirtuality | No |
Databricks | Yes |
Denodo 7 | Yes |
Denodo 8 | Yes |
Dremio | Yes |
Dremio 11+ | Yes |
Exasol | Yes |
Firebolt | Yes |
Google BigQuery Legacy SQL | Yes |
Google BigQuery Standard SQL | Yes |
Google Cloud PostgreSQL | Yes |
Google Cloud SQL | Yes |
Google Spanner | Yes |
Greenplum | Yes |
HyperSQL | Yes |
IBM Netezza | Yes |
MariaDB | Yes |
Microsoft Azure PostgreSQL | Yes |
Microsoft Azure SQL Database | Yes |
Microsoft Azure Synapse Analytics | Yes |
Microsoft SQL Server 2008+ | Yes |
Microsoft SQL Server 2012+ | Yes |
Microsoft SQL Server 2016 | Yes |
Microsoft SQL Server 2017+ | Yes |
MongoBI | No |
MySQL | Yes |
MySQL 8.0.12+ | Yes |
Oracle | Yes |
Oracle ADWC | Yes |
PostgreSQL 9.5+ | Yes |
PostgreSQL pre-9.5 | Yes |
PrestoDB | Yes |
PrestoSQL | Yes |
SAP HANA 2+ | Yes |
SingleStore | Yes |
SingleStore 7+ | Yes |
Snowflake | Yes |
Teradata | No |
Trino | Yes |
Vector | No |
Vertica | Yes |
Prerequisites
To connect Looker to a database that requires an unpackaged JDBC driver, you will need:
- Command line access to your Looker server.
- The JDBC driver as a JAR file. The dialect's specific documentation may have instructions on where to download this file; otherwise, we assume you have access to the JAR file needed.
- The driver symbol for your dialect. A driver symbol is a string value that Looker uses internally to match the dialect to the driver. The examples on this page use the generic value
driver_symbol
. See the list of driver symbols on this page for the symbols Looker uses to register JDBC drivers to dialects. - The YAML driver entry for your dialect to be added to the
custom_jdbc_config.yml
configuration file. See the Driver entries in the YAML configuration file section on this page for more information.
Driver entries in the YAML configuration file
Here is an example driver entry in the custom_jdbc_config.yml
file:
- name: driver_symbol
dir_name: driver_symbol
module_path: com.dialect.jdbc.DialectDriver
override_jdbc_url_subprotocol: driver_subprotocol # optional
When writing the driver entry for your dialect:
- The file
custom_jdbc_config.yml
is YAML-based, which means that indentation and spacing matter. - The
name
anddir_name
attributes must be the driver symbol that Looker expects for you dialect when registering JDBC drivers. - It is possible to use the attribute
file_name
instead ofdir_name
containing the relative path fromcustom_jdbc_drivers
to the JDBC driver JAR file.dir_name
is recommended because it promotes keeping multiple drivers isolated to their own directories and reduces the chance of Java classes colliding. - The
module_path
property will depend on the specific JDBC driver. It should be the fully qualified path to the Java driver class. This example uses a generic value, but to find the specificmodule_path
the driver uses consult its documentation on how to register the driver class. - The
override_jdbc_url_subprotocol
is an optional argument used to override the subprotocol used in the JDBC string that Looker sends to the database. A typical JDBC string will look like this:
jdbc:mysql://localhost:3306/database_name[?propertyName1][=propertyValue1]
Where mysql
is the JDBC subprotocol being used.
If you specify override_jdbc_url_subprotocol: driver_subprotocol
, then this JDBC string will become:
jdbc:driver_subprotocol://localhost:3306/database_name[?propertyName1][=propertyValue1]
This option is required if you need to use an unpackaged JDBC driver that requires a URL subprotocol other than Looker's default URL subprotocol. For the most part, this is not necessary unless the dialect's documentation explicitly says that is it necessary. MongoBI is an example of a dialect that requires this option.
Installing unpackaged JDBC drivers
Change into the Looker application base directory. For this document we will assume it is
looker
cd looker
Create a directory called
custom_jdbc_drivers
. This is the top-level directory for all unpackaged JDBC driver installations. The path to this directory should belooker/custom_jdbc_drivers
mkdir custom_jdbc_drivers
In the
custom_jdbc_drivers
directory, create a subdirectory named with your dialect's driver symbol. This example uses the generic valuedriver_symbol
. The resulting path to the directory will look likelooker/custom_jdbc_drivers/driver_symbol
cd custom_jdbc_drivers mkdir driver_symbol
Place the JDBC driver files for your dialect into this directory. The method for this depends on where your dialect's driver can be found and uploaded onto the server, but be sure that the relevant JAR file(s) are inside the
driver_symbol
directory:looker/custom_jdbc_drivers/driver_symbol/
For example:
looker/custom_jdbc_drivers/driver_symbol/DialectDriver.jar
Moving the necessary files onto the Looker server will vary based on where you get the driver files and your preference for file transferring. Examples of commands for transferring files into this directory are
wget
,scp
,curl
, etc.Change back into the Looker application directory and create a configuration file named
custom_jdbc_config.yml
. The path to this file should belooker/custom_jdbc_config.yml
. This file will contain the information Looker needs to locate and register the custom JDBC driver.cd looker vim custom_jdbc_config.yml
Add a new entry for your dialect into the
custom_jdbc_config.yml
configuration file. See the Driver entries in the YAML configuration file section on this page for information on driver entries.- name: driver_symbol dir_name: driver_symbol module_path: com.dialect.jdbc.DialectDriver
Create or update the file
lookerstart.cfg
so that the Looker application starts up with the unpackaged JDBC driver configuration. The path to this file should belooker/lookerstart.cfg
. Add the option--use-custom-jdbc-config
. If there are other options, append this to the end of the Looker startup options:LOOKERARGS="--use-custom-jdbc-config"
If you have
LOOKERARGS
set somewhere other thanlookerstart.cfg
, like in an environment variable, you may add this startup flag there. Alternatively, you can setLOOKERARGS="${LOOKERARGS} --use-custom-jdbc-config"
so that the existing values will be expanded into this file.Restart the Looker application. In this command, use the name of your Looker startup script, such as
./looker
or./looker.sh
./looker restart
or
none ./looker stop ./looker start
Multiple unpackaged JDBC drivers
If you need to configure more than one dialect to use unpackaged JDBC drivers, the above process still applies. The custom_jdbc_drivers
directory will have multiple dialect
subdirectories with their own driver JARs, and the custom_jdbc_config.yml
file will have multiple entries:
ls looker/custom_jdbc_drivers
driver_symbol_1 driver_symbol_2
ls looker/custom_jdbc_drivers/driver_symbol_1
Dialect1Driver.jar
- name: driver_symbol_1
dir_name: driver_symbol_1
module_path: com.dialect.jdbc.Dialect1Driver
- name: driver_symbol_2
dir_name: driver_symbol_2
module_path: com.dialect.jdbc.Dialect2Driver