def test_empty_result_count_typed_notau_prepost(self):
schema_all = copy.deepcopy(schema)
schema_all['PUMS.PUMS'].censor_dims = False
reader = PandasReader(df, schema)
query = QueryParser(schema).queries(
"SELECT COUNT(*) as c FROM PUMS.PUMS WHERE age > 100")[0]
private_reader = PrivateReader(reader,
schema_all,
privacy=Privacy(epsilon=1.0))
private_reader._execute_ast(query, True)
for i in range(3):
print(private_reader._options)
trs = private_reader._execute_ast(query, True)
print("empty query")
print(trs)
assert (len(trs) == 2)
def test_check_thresholds_gauss(self):
# check tau for various privacy parameters
epsilons = [0.1, 2.0]
max_contribs = [1, 3]
deltas = [10E-5, 10E-15]
query = "SELECT COUNT(*) FROM PUMS.PUMS GROUP BY married"
reader = PandasReader(df, schema)
qp = QueryParser(schema)
q = qp.query(query)
for eps in epsilons:
for d in max_contribs:
for delta in deltas:
privacy = Privacy(epsilon=eps, delta=delta)
privacy.mechanisms.map[Stat.threshold] = Mechanism.gaussian
# using slightly different formulations of same formula from different papers
# make sure private_reader round-trips
gaus_scale = math.sqrt(d) * math.sqrt(
2 * math.log(1.25 / delta)) / eps
gaus_rho = 1 + gaus_scale * math.sqrt(
2 * math.log(d / math.sqrt(2 * math.pi * delta)))
schema_c = copy.copy(schema)
schema_c["PUMS.PUMS"].max_ids = d
private_reader = PrivateReader(reader,
metadata=schema_c,
privacy=privacy)
assert (private_reader._options.max_contrib == d)
r = private_reader._execute_ast(q)
assert (math.isclose(private_reader.tau,
gaus_rho,
rel_tol=0.03,
abs_tol=2))
def run_agg_query(self, df, metadata, query, confidence, get_exact=True):
"""
Run the query using the private reader and input query
Get query response back
"""
reader = PandasReader(df, metadata)
actual = 0.0
# VAR not supported in Pandas Reader. So not needed to fetch actual on every aggregation
if get_exact:
actual = reader.execute(query)[1:][0][0]
private_reader = PrivateReader(reader,
metadata,
privacy=Privacy(epsilon=self.epsilon))
query_ast = private_reader.parse_query_string(query)
noisy_values = []
low_bounds = []
high_bounds = []
for idx in range(self.repeat_count):
res = private_reader._execute_ast(query_ast, True)
# Disabled because confidence interval not available in report
# interval = res.report[res.colnames[0]].intervals[confidence]
# low_bounds.append(interval[0].low)
# high_bounds.append(interval[0].high)
noisy_values.append(res[1:][0][0])
return np.array(noisy_values), actual, low_bounds, high_bounds
def release(self, dataset: object) -> Report:
"""
Dataset is a collection of [Dataset Metadata, PandasReader]
Releases response to SQL query based on the number of repetitions
requested by eval_params if actual is set of False.
"""
private_reader = PrivateReader(dataset[0], dataset[1],
self.privacy_params.epsilon)
query_ast = private_reader.parse_query_string(self.algorithm)
srs_orig = private_reader.reader._execute_ast_df(query_ast)
noisy_values = []
for idx in range(self.eval_params.repeat_count):
res = private_reader._execute_ast(query_ast, True)
if not res[1:]:
return Report({"__key__": "noisy_values_empty"})
else:
noisy_values.append(res[1:][0][0])
return Report({"__key__": noisy_values})
def run_agg_query_df(self,
df,
metadata,
query,
confidence,
file_name="d1"):
"""
Run the query using the private reader and input query
Get query response back for multiple dimensions and aggregations
"""
# Getting exact result
reader = PandasReader(df, metadata)
exact_res = reader.execute(query)[1:]
private_reader = PrivateReader(reader,
metadata,
privacy=Privacy(epsilon=self.epsilon))
query_ast = private_reader.parse_query_string(query)
# Distinguishing dimension and measure columns
sample_res = private_reader._execute_ast(query_ast, True)
headers = sample_res[0]
dim_cols = []
num_cols = []
out_syms = query_ast.all_symbols()
out_types = [s[1].type() for s in out_syms]
out_col_names = [s[0] for s in out_syms]
for col, ctype in zip(out_col_names, out_types):
if ctype == "string":
dim_cols.append(col)
else:
num_cols.append(col)
# Repeated query and store results
res = []
for idx in range(self.repeat_count):
dim_rows = []
num_rows = []
singleres = private_reader._execute_ast_df(query_ast,
cache_exact=True)
# values = singleres[col]
for col in dim_cols:
dim_rows.append(singleres[col].tolist())
for col in num_cols:
values = singleres[col].tolist()
num_rows.append(list(zip(values)))
res.extend(list(zip(*dim_rows, *num_rows)))
exact_df = pd.DataFrame(exact_res, columns=headers)
noisy_df = pd.DataFrame(res, columns=headers)
# Add a dummy dimension column for cases where no dimensions available for merging D1 and D2
if len(dim_cols) == 0:
dim_cols.append("__dim__")
if dim_cols[0] == "__dim__":
exact_df[dim_cols[0]] = ["key"] * len(exact_df)
noisy_df[dim_cols[0]] = ["key"] * len(noisy_df)
return noisy_df, exact_df, dim_cols, num_cols
