def test_filter_iterator_interrupt():
expression = "?p = <http://schema.org/eligibleRegion>"
iterator, card = hdtDoc.search_triples(triple['subject'], triple['predicate'], triple['object'])
scan = ProjectionIterator(ScanIterator(iterator, triple, card))
iterator = FilterIterator(scan, expression)
(results, saved, done) = engine.execute(iterator, 10e-7)
assert len(results) <= 4
for b in results:
assert b['?p'] == 'http://schema.org/eligibleRegion'
assert b['?o'] in [
'http://db.uwaterloo.ca/~galuc/wsdbm/Country0',
'http://db.uwaterloo.ca/~galuc/wsdbm/Country1',
'http://db.uwaterloo.ca/~galuc/wsdbm/Country4',
'http://db.uwaterloo.ca/~galuc/wsdbm/Country9'
]
tmp = len(results)
reloaded = load(saved.SerializeToString(), DummyDataset(hdtDoc, 'watdiv100'))
(results, saved, done) = engine.execute(reloaded, 10e7)
assert len(results) + tmp == 4
for b in results:
assert b['?p'] == 'http://schema.org/eligibleRegion'
assert b['?o'] in [
'http://db.uwaterloo.ca/~galuc/wsdbm/Country0',
'http://db.uwaterloo.ca/~galuc/wsdbm/Country1',
'http://db.uwaterloo.ca/~galuc/wsdbm/Country4',
'http://db.uwaterloo.ca/~galuc/wsdbm/Country9'
]
assert done
def build_query_plan(query, db_connector, saved_plan=None, projection=None):
cardinalities = []
if saved_plan is not None:
return load(saved_plan, db_connector), []
# optional = query['optional'] if 'optional' in query and len(query['optional']) > 0 else None
root = None
if query['type'] == 'union':
root, cardinalities = build_union_plan(query['union'], db_connector,
projection)
elif query['type'] == 'bgp':
root, cardinalities = build_join_plan(query['bgp'],
db_connector,
projection=projection)
else:
raise Exception('Unkown query type found during query optimization')
# apply filter clause(s)
if 'filters' in query and len(query['filters']) > 0:
# reduce all filters in a conjunctive expression
expression = reduce(lambda x, y: "({}) && ({})".format(x, y),
query['filters'])
root = FilterIterator(root, expression)
return root, cardinalities
def execute_query(query, default_graph_uri, next_link, dataset, mimetype, url):
"""Execute a query using the SageEngine and returns the appropriate HTTP response"""
graph_name = format_graph_uri(default_graph_uri, url)
if not dataset.has_graph(graph_name):
return sage_http_error(
"No RDF graph matching the default URI provided was found.")
graph = dataset.get_graph(graph_name)
# decode next_link or build query execution plan
cardinalities = dict()
start = time()
if next_link is not None:
plan = load(decode_saved_plan(next_link), dataset)
else:
plan, cardinalities = parse_query(query, dataset, graph_name, url)
loading_time = (time() - start) * 1000
# execute query
engine = SageEngine()
quota = graph.quota / 1000
max_results = graph.max_results
bindings, saved_plan, is_done = engine.execute(plan, quota, max_results)
# compute controls for the next page
start = time()
next_page = None
if not is_done:
next_page = encode_saved_plan(saved_plan)
exportTime = (time() - start) * 1000
stats = {
"cardinalities": cardinalities,
"import": loading_time,
"export": exportTime
}
# send response
if mimetype == "application/sparql-results+json":
return Response(responses.w3c_json_streaming(bindings, next_page,
stats, url),
content_type='application/json')
if mimetype == "application/xml" or mimetype == "application/sparql-results+xml":
return Response(responses.w3c_xml(bindings, next_page, stats),
content_type="application/xml")
if mimetype == "application/json":
return Response(responses.raw_json_streaming(bindings, next_page,
stats, url),
content_type='application/json')
# otherwise, return the HTML version
return render_template("sage_page.html",
query=query,
default_graph_uri=default_graph_uri,
bindings=bindings,
next_page=next_page,
stats=stats)
def build_query_plan(query, dataset, default_graph, saved_plan=None):
"""Build a pipeline of iterators used to evaluate a query"""
cardinalities = []
if saved_plan is not None:
return load(saved_plan, dataset), []
root = None
if query['type'] == 'union':
root, cardinalities = build_union_plan(query['union'], dataset, default_graph)
elif query['type'] == 'bgp':
root, cardinalities = build_join_plan(query['bgp'], dataset, default_graph)
else:
raise Exception('Unkown query type found during query optimization')
# apply (possible) filter clause(s)
if 'filters' in query and len(query['filters']) > 0:
# exclude empty strings
filters = list(filter(lambda x: len(x) > 0, query['filters']))
if len(filters) > 0:
# reduce all filters in a conjunctive expression
expression = reduce(lambda x, y: "({}) && ({})".format(x, y), filters)
root = FilterIterator(root, expression)
return root, cardinalities
