def test_large_compile():
"""
Tests that compiling a large expression tree finishes
within a reasonable amount of time
"""
num_columns = 20
num_joins = 7
class MockBigQueryClient(bq.BigQueryClient):
def __init__(self):
pass
names = [f"col_{i}" for i in range(num_columns)]
schema = ibis.Schema(names, ['string'] * num_columns)
ibis_client = MockBigQueryClient()
table = TableExpr(
ops.SQLQueryResult("select * from t", schema, ibis_client)
)
for _ in range(num_joins):
table = table.mutate(dummy=ibis.literal(""))
table = table.left_join(table, ["dummy"])[[table]]
start = datetime.datetime.now()
table.compile()
delta = datetime.datetime.now() - start
assert delta.total_seconds() < 10
def sql(self, query):
"""Convert a SQL query to an Ibis table expression.
Parameters
----------
query : string
Returns
-------
table : TableExpr
"""
# Get the schema by adding a LIMIT 0 on to the end of the query. If
# there is already a limit in the query, we find and remove it
limited_query = 'SELECT * FROM ({}) t0 LIMIT 0'.format(query)
schema = self._get_schema_using_query(limited_query)
return ops.SQLQueryResult(query, schema, self).to_expr()
def sql(self, query):
"""
Convert a MSSQL query to an Ibis table expression
Parameters
----------
query: string
SQL query to execute on connection
Returns
-------
table : TableExpr
"""
limited_query = 'SELECT TOP 0 * FROM ({}) t0'.format(query)
schema = self._get_schema_using_query(limited_query)
return ops.SQLQueryResult(query, schema, self).to_expr()
def sql(self, query: str):
"""
Convert a SQL query to an Ibis table expression.
Parameters
----------
query : string
Returns
-------
table : TableExpr
"""
# Remove `;` + `--` (comment)
query = re.sub(r'\s*;\s*--', '\n--', query.strip())
# Remove trailing ;
query = re.sub(r'\s*;\s*$', '', query.strip())
schema = self._get_schema_using_validator(query)
return ops.SQLQueryResult(query, schema, self).to_expr()
def sql(self, query):
"""
Convert a SQL query to an Ibis table expression
Parameters
----------
Returns
-------
table : TableExpr
"""
# Get the schema by adding a LIMIT 0 on to the end of the query. If
# there is already a limit in the query, we find and remove it
limited_query = _set_limit(query, 0)
schema = self._get_schema_using_query(limited_query)
node = ops.SQLQueryResult(query, schema, self)
return ir.TableExpr(node)
def sql(self, query):
"""
Convert a SQL query to an Ibis table expression
Parameters
----------
Returns
-------
table : TableExpr
"""
if pymapd_dtype is None:
raise com.UnsupportedOperationError(
'This method is available just on Python version >= 3.6.')
# Remove `;` + `--` (comment)
query = re.sub(r'\s*;\s*--', '\n--', query.strip())
# Remove trailing ;
query = re.sub(r'\s*;\s*$', '', query.strip())
schema = self._get_schema_using_validator(query)
return ops.SQLQueryResult(query, schema, self).to_expr()
def prevent_rewrite(self, client=None) -> TableExpr:
"""Prevent optimization from happening below this expression.
Only valid on SQL-string generating backends.
Parameters
----------
client
A client to use to create the SQLQueryResult operation. This can be
useful if you're compiling an expression that derives from an
`UnboundTable` operation.
Returns
-------
TableExpr
An opaque SQL query
"""
from .. import operations as ops
if client is None:
client = self._find_backend()
query = client.compile(self)
return ops.SQLQueryResult(query, self.schema(), client).to_expr()
