[overpass] transaction log: read_aborted()

[<>]

Hello,
For one particular query, I see the line read_aborted() - It ran for more than
15 min.
Is there a way to diagnose why the query was aborted? i.e. did it cross some
query time to run threshold setting.

I found purge_setting initialised to 900. But I couldn't figure out how it was
being used.

Also, there doesn't seem to be an http response. I don't see anything in the
nginx logs either.

Thanks.