Troubleshooting


This section covers some of the issues that can occur with your qbo instance and provides useful troubleshooting steps to help you resolve an issue yourself.

Our library of troubleshooting resources continues to grow. Check back often for the latest additions.

Issues


qbo responds with I’m unable to generate the vizy

  • All the configured entities are visible on the right bottom side on the homepage of the user.

../../_images/troubleshooting-UserHomePage.jpg

Upon clicking on the entity bot could reply "Sorry, I'm unable to generate the vizy." which means bot failed to reply.

The leading reason for I’m unable to generate the vizy error is qbo attempting to access a large volume of data from the backend data source. Many data sources impose a limit on the size of the results returned via API calls. While we limit the number of rows returned per query to 1000, it is still possible that one may exceed the limit imposed by the backend data source. Queries that attempt to access and present the entire entity, e.g. when a user clicks on the entity name from the home page, may result in the aforementioned error.

You can check logs for the more detailed exception:

exception summary
01-20 15:23:43.380|ERROR|failed to generate a vizy, details: MultiError: with 2 suppressed errors:
    error #1/2: QueryFailedError: ER_NET_PACKET_TOO_LARGE: Got a packet bigger than 'max_allowed_packet' bytes

A couple of ways to fix this would be:

  1. limit the number of visible attributes of the entity to a lower number

../../_images/troubleshooting-AttributesToTen.jpg
  1. For MariaDB, do the following

Open file /etc/my.cnf.d/server.cnf and set the value of max_allowed_packet to 128M.

configuration file content
    # These groups are read by MariaDB server.
    # Use it for options that only the server (but not clients) should see
    #
    # See the examples of server my.cnf files in /usr/share/mysql/
    #

    # this is read by the standalone daemon and embedded servers
    [server]

    # this is only for the mysqld standalone daemon
    [mysqld]
    innodb_file_format=Barracuda
    innodb_file_per_table=ON
    innodb_large_prefix=ON
    max_allowed_packet=128M
    # this is only for embedded server
    [embedded]

    # This group is only read by MariaDB-5.5 servers.
    # If you use the same .cnf file for MariaDB of different versions,
    # use this group for options that older servers don't understand
    [mysqld-5.5]

    # These two groups are only read by MariaDB servers, not by MySQL.
    # If you use the same .cnf file for MySQL and MariaDB,
    # you can put MariaDB-only options here
    [mariadb]

    [mariadb-5.5]

Configuration modifications become active only after a server restart, which requires restarting the specific operating system service as follows.

On RedHat:

$ sudo service mariadb restart

On Ubuntu:

$ sudo service mysql restart

There may be other reasons for the aforementioned error, and a detailed diagnostic would be required for such cases. Please contact the product support team to report the issue.

Long texts not allowed

Datasets where one of the columns can contain long texts is not supported in qbo. In general, please avoid having strings with more than 10 words in a column.

If a dataset with a very long descriptive text is added in the qbo and when you reload it by clicking on the button Reload in the Data Sources section, it will fail with a message Reloading failed, try reloading the querybot again.

In this scenario please delete that attribute with a very long text from the querybot model (not necessarily from the actual table in the DB) and reload again.