Query on telemetry.main succeeds in BQ console, but reports backendError in STMO

[jklukas]

When trying to run https://sql.telemetry.mozilla.org/queries/77064/source which references just a few columns in telemetry.main but covers a several-month timerange, we see the following error consistently in STMO:

Error running query: b'{\n "error": {\n "code": 503,\n "message": "Error encountered during execution. Retrying may solve the problem.",\n "errors": [\n {\n "message": "Error encountered during execution. Retrying may solve the problem.",\n "domain": "global",\n "reason": "backendError"\n }\n ],\n "status": "INTERNAL"\n }\n}\n'

Yet, the same query can run successfully in the BQ console.

I initially assumed this was a real BQ-level error related to large metadata scans due to the wide timerange, which can return a message like this from a query job. Perhaps this is coming from something other than the query job itself?

cc @Standard8