5  Query Engine

The query engine does the work of breaking down a SQL query and executing it.

5.1 Restarting the engine

When you add a new data source to EdgeSet, you must restart the query engine in order for EdgeSet to connect to the data source and map the data into the catalog.

You can also restart the query engine any time from the Engine menu.

5.2 Engine stats

Navigating to the Engine menu will show you statistics about the query engine, such as the number of running and queued queries.

No user queries have run on this EdgeSet server yet

5.3 Query Management

You can view and manage currently running or queued queries in the User Queries and System Queries tables.

5.3.1 User Queries

The User Queries table will display the list of currently running or queued queries executed by users of Edgeset with the following details:

  • Creation date: The date and time in which the query was submitted formatted in local timezone.
  • User: The user running the query.
  • Query: The query string.
  • Status: Status of the query.
  • Action: Display’s a cancellation link to cancel the associated query.

User Queries panel displaying a table of queries and Cancel all queries button

You can cancel a query individually associcated with a user or cancel all the queries by clicking the Cancel all queries button present in the header of the query management tables.

5.3.2 System Queries

The System Queries table displays the list of currently running or queued queries executed by the Edgeset user interface (such as for displaying the data catalog). System queries are special in that they don’t count towards the concurrent query limit and are executed as soon as possible.

Note: Unless necessary it’s advisable not to cancel the displayed system queries as it could lead to unexpected errors for users.

5.4 Console

If adding a data source doesn’t work as expected, you can open the Console to view log messages.

5.4.1 Opening the Console

Open the console by clicking on Console in the menu, a panel will pop out from the bottom of the page.

an empty console

Note that the console only displays the last 1000 log entries.