Troubleshooting
This page discusses some tips to troubleshoot issues with Virtual Graphs.
Page Contents
Overview
The most common problem with virtual graphs is configuring the mappings correctly. Each database has different casing behavior, quoting characters, etc. The following features can be helpful when troubleshooting these issues.
Enable Debug Logging
Stardog uses log4j2 for logging. You can enable debug logging at the virtual graph level by adding this line to the Loggers section of your log4j2.xml file:
<Logger name="com.complexible.stardog.virtual" level="DEBUG" additivity="false">
<AppenderRef ref="stardogAppender"/>
</Logger>
This will increase the logging to the stardog.log file (but not to the console).
See our section on Logging for more information on how to configure your log4j2.xml file.
Metadata Inspection Tool
You can use the metadata inspection tool to retrieve the schema and column names as they appear to Stardog when connecting via the virtual graph connection properties (driver name, connection string, credentials, etc.). The inspection tool is accessed using the command-line interface (CLI). The documentation is accessed using the help command:
$ stardog-admin help virtual source_metadata
Alternatively, see the virtual source_metadata manual page in the Stardog Admin CLI Reference Manual.
The metadata inspection tool is for JDBC-type data sources only. Also, it is a client-side application. It does not connect to Stardog but to the backing database directly, so it is possible for there to be different issues relating to the firewall, class loading, or other problems that Stardog will encounter. For this reason, the best practice is to run this command-line tool from the server that is hosting Stardog.
The JDBC driver must be visible to the CLI Java application. You can copy the driver to the client/cli folder for this purpose.