sqlalchemy.exc.ResourceClosedError from Builder.getOldestRequestTime()

[p12tic]

Got this exception on custom build based on 2.10.1. This should not happen, but I'm not sure what may cause it. Logs follow:

 [twisted.internet.defer#critical] 
	Traceback (most recent call last):
	  File "<...>/twisted/internet/defer.py", line 501, in errback
	    self._startRunCallbacks(fail)
	  File "<...>/twisted/internet/defer.py", line 568, in _startRunCallbacks
	    self._runCallbacks()
	  File "<...>/twisted/internet/defer.py", line 654, in _runCallbacks
	    current.result = callback(current.result, *args, **kw)
	  File "<...>/twisted/internet/defer.py", line 1475, in gotResult
	    _inlineCallbacks(r, g, status)
	--- <exception caught here> ---
	  File "<...>/twisted/internet/defer.py", line 1416, in _inlineCallbacks
	    result = result.throwExceptionIntoGenerator(g)
	  File "<...>/twisted/python/failure.py", line 512, in throwExceptionIntoGenerator
	    return g.throw(self.type, self.value, self.tb)
	  File "<...>/buildbot/master/buildbot/process/builder.py", line 169, in getOldestRequestTime
	    order=['submitted_at'], limit=1)
	  File "<...>/twisted/internet/defer.py", line 1416, in _inlineCallbacks
	    result = result.throwExceptionIntoGenerator(g)
	  File "<...>/twisted/python/failure.py", line 512, in throwExceptionIntoGenerator
	    return g.throw(self.type, self.value, self.tb)
	  File "<...>/buildbot/master/buildbot/data/connector.py", line 125, in get
	    rv = yield endpoint.get(resultSpec, kwargs)
	  File "<...>/twisted/internet/defer.py", line 1416, in _inlineCallbacks
	    result = result.throwExceptionIntoGenerator(g)
	  File "<...>/twisted/python/failure.py", line 512, in throwExceptionIntoGenerator
	    return g.throw(self.type, self.value, self.tb)
	  File "<...>/buildbot/master/buildbot/data/buildrequests.py", line 169, in get
	    resultSpec=resultSpec)
	  File "<...>/twisted/internet/defer.py", line 1416, in _inlineCallbacks
	    result = result.throwExceptionIntoGenerator(g)
	  File "<...>/twisted/python/failure.py", line 512, in throwExceptionIntoGenerator
	    return g.throw(self.type, self.value, self.tb)
	  File "<...>/buildbot/master/buildbot/db/buildrequests.py", line 133, in getBuildRequests
	    res = yield self.db.pool.do(thd)
	  File "<...>/twisted/internet/defer.py", line 1416, in _inlineCallbacks
	    result = result.throwExceptionIntoGenerator(g)
	  File "<...>/twisted/python/failure.py", line 512, in throwExceptionIntoGenerator
	    return g.throw(self.type, self.value, self.tb)
	  File "<...>/buildbot/master/buildbot/db/pool.py", line 229, in do
	    args, kwargs)
	  File "<...>/twisted/python/threadpool.py", line 250, in inContext
	    result = inContext.theWork()
	  File "<...>/twisted/python/threadpool.py", line 266, in <lambda>
	    inContext.theWork = lambda: context.call(ctx, func, *args, **kw)
	  File "<...>/twisted/python/context.py", line 122, in callWithContext
	    return self.currentContext().callWithContext(ctx, func, *args, **kw)
	  File "<...>/twisted/python/context.py", line 85, in callWithContext
	    return func(*args,**kw)
	  File "<...>/buildbot/master/buildbot/db/pool.py", line 190, in __thd
	    rv = callable(arg, *args, **kwargs)
	  File "<...>/buildbot/master/buildbot/db/buildrequests.py", line 127, in thd
	    lambda r: self._brdictFromRow(r, self.db.master.masterid)))
	  File "<...>/buildbot/master/buildbot/data/resultspec.py", line 346, in thd_execute
	    rv = [dictFromRow(row) for row in res.fetchall()]
	  File "<...>/sqlalchemy/engine/result.py", line 1289, in fetchall
	    e, None, None, self.cursor, self.context
	  File "<...>/sqlalchemy/engine/base.py", line 1514, in _handle_dbapi_exception
	    util.raise_(exc_info[1], with_traceback=exc_info[2])
	  File "<...>/sqlalchemy/util/compat.py", line 182, in raise_
	    raise exception
	  File "<...>/sqlalchemy/engine/result.py", line 1284, in fetchall
	    l = self.process_rows(self._fetchall_impl())
	  File "<...>/sqlalchemy/engine/result.py", line 1232, in _fetchall_impl
	    return self._non_result([], err)
	  File "<...>/sqlalchemy/engine/result.py", line 1241, in _non_result
	    replace_context=err,
	  File "<...>/sqlalchemy/util/compat.py", line 182, in raise_
	    raise exception
	sqlalchemy.exc.ResourceClosedError: This result object does not return rows. It has been closed automatically.