Skip to content

New: AbstractQuerySet.__Iter__ is no more greedy #389

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
alanjds wants to merge 2 commits into from
Closed

New: AbstractQuerySet.__Iter__ is no more greedy #389

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
49abb35
Debug for automatic pagination machinery
alanjds Aug 20, 2015
d433631
AbstractQuerySet.__iter__ is no more greedy. Fetches on demand.
alanjds Aug 20, 2015
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 2 additions & 0 deletions cassandra/cluster.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2965,7 +2965,9 @@ def start_fetching_next_page(self):

.. versionadded:: 2.0.0
"""
log.debug('Pagination: Fetching next page')
if not self._paging_state:
log.debug('Pagination: No more pages to fetch')
raise QueryExhausted()

self._make_query_plan()
Expand Down
39 changes: 26 additions & 13 deletions cassandra/cqlengine/query.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -258,7 +258,9 @@ def __init__(self, model):
# results cache
self._result_cache = None
self._result_idx = None
self._result_generator = None

self._count = None
self._batch = None
self._ttl = getattr(model, '__default_ttl__', None)
self._consistency = None
Expand Down Expand Up @@ -308,7 +310,7 @@ def __deepcopy__(self, memo):

def __len__(self):
self._execute_query()
return len(self._result_cache)
return self.count()

# ----query generation / execution----

Expand Down Expand Up @@ -340,7 +342,8 @@ def _execute_query(self):
if self._batch:
raise CQLEngineException("Only inserts, updates, and deletes are available in batch mode")
if self._result_cache is None:
self._result_cache = list(self._execute(self._select_query()))
self._result_generator = (i for i in self._execute(self._select_query()))
self._result_cache = []
self._construct_result = self._get_result_constructor()

def _fill_result_cache_to_idx(self, idx):
Expand All @@ -354,21 +357,32 @@ def _fill_result_cache_to_idx(self, idx):
else:
for idx in range(qty):
self._result_idx += 1
self._result_cache[self._result_idx] = self._construct_result(self._result_cache[self._result_idx])
while True:
try:
self._result_cache[self._result_idx] = self._construct_result(self._result_cache[self._result_idx])
break
except IndexError:
self._result_cache.append(next(self._result_generator))

def __iter__(self):
self._execute_query()

for idx in range(len(self._result_cache)):
instance = self._result_cache[idx]
for idx in range(self.count()):
while True:
try:
instance = self._result_cache[idx]
break
except IndexError:
self._result_cache.append(next(self._result_generator))

if isinstance(instance, dict):
self._fill_result_cache_to_idx(idx)
yield self._result_cache[idx]

def __getitem__(self, s):
self._execute_query()

num_results = len(self._result_cache)
num_results = self.count()

if isinstance(s, slice):
# calculate the amount of results that need to be loaded
Expand Down Expand Up @@ -577,10 +591,10 @@ def get(self, *args, **kwargs):
return self.filter(*args, **kwargs).get()

self._execute_query()
if len(self._result_cache) == 0:
if self.count() == 0:
raise self.model.DoesNotExist
elif len(self._result_cache) > 1:
raise self.model.MultipleObjectsReturned('{0} objects found'.format(len(self._result_cache)))
elif self.count() > 1:
raise self.model.MultipleObjectsReturned('{0} objects found'.format(self.count()))
else:
return self[0]

Expand Down Expand Up @@ -641,13 +655,12 @@ def count(self):
if self._batch:
raise CQLEngineException("Only inserts, updates, and deletes are available in batch mode")

if self._result_cache is None:
if self._count is None:
query = self._select_query()
query.count = True
result = self._execute(query)
return result[0]['count']
else:
return len(self._result_cache)
self._count = result[0]['count']
return self._count

def limit(self, v):
"""
Expand Down