Failed to run query: Database is not registered

[smowton]

Happens about half the time I select a new database, make a quick query and try to run it:

                              com.semmle.util.exception.UserError: Database is not registered: /private/tmp/db
                              	at com.semmle.cli2.execute.queryServer2.QueryServer2BackendManager.withDB(QueryServer2BackendManager.java:175)
                              	at com.semmle.cli2.execute.queryServer2.QueryServer2BackendManager.withDBShared(QueryServer2BackendManager.java:70)
                              	at com.semmle.cli2.execute.queryServer2.QueryServer2Command$Impl.lambda$runQuery$26(QueryServer2Command.java:580)
                              	at com.semmle.util.concurrent.FutureUtils.supplyCompose(FutureUtils.java:248)
                              	at com.semmle.cli2.execute.queryServer2.QueryServer2Command$Impl.lambda$runQuery$28(QueryServer2Command.java:560)
                              	at com.semmle.cli2.execute.queryServer2.QueryServer2Command$Impl.lambda$withProgressAndCancellation$15(QueryServer2Command.java:405)
                              	at com.semmle.util.concurrent.FutureUtils.supplyCompose(FutureUtils.java:248)
                              	at com.semmle.cli2.execute.queryServer2.QueryServer2Command$Impl.lambda$withProgressAndCancellation$16(QueryServer2Command.java:404)
                              	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
                              	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)

Restarting the query server always fixes the situation.

[aeisenberg]

This error happens because the query server needs to have a lock on the database in order to operate on it. Before each query-ish operation, the extension is supposed to register the database so that it can be used. For some reason, this is not happening.

Or, the database is getting registered, but then another database is getting re-registered right before the query server tries to run something on the first database.
Either way, this is a bug. (edited)

Is this bug related to how many databases are currently in your database view? Or is one or more of them a test database?