openstack/deb-python-cassandra-driver
Code Issues Proposed changes

Merge pull request #323 from datastax/304

Browse Source 
PYTHON-304 - Add documentation for connection pool settings
This commit is contained in:
Adam Holmberg
2015-05-22 11:13:23 -05:00
parent db88fe16ac 2302a7848f
commit 0209d2befa
2 changed files with 26 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
cassandra/cluster.py
View File

@@ -660,6 +660,13 @@ class Cluster(object):
return self._min_requests_per_connection[host_distance] return self._min_requests_per_connection[host_distance]
def set_min_requests_per_connection(self, host_distance, min_requests): def set_min_requests_per_connection(self, host_distance, min_requests):
"""
Sets a threshold for concurrent requests per connection, below which
connections will be considered for disposal (down to core connections;
see :meth:`~Cluster.set_core_connections_per_host`).
Pertains to connection pool management in protocol versions {1,2}.
"""
if self.protocol_version >= 3: if self.protocol_version >= 3:
raise UnsupportedOperation( raise UnsupportedOperation(
"Cluster.set_min_requests_per_connection() only has an effect " "Cluster.set_min_requests_per_connection() only has an effect "
@@ -670,6 +677,13 @@ class Cluster(object):
return self._max_requests_per_connection[host_distance] return self._max_requests_per_connection[host_distance]
def set_max_requests_per_connection(self, host_distance, max_requests): def set_max_requests_per_connection(self, host_distance, max_requests):
"""
Sets a threshold for concurrent requests per connection, above which new
connections will be created to a host (up to max connections;
see :meth:`~Cluster.set_max_connections_per_host`).
Pertains to connection pool management in protocol versions {1,2}.
"""
if self.protocol_version >= 3: if self.protocol_version >= 3:
raise UnsupportedOperation( raise UnsupportedOperation(
"Cluster.set_max_requests_per_connection() only has an effect " "Cluster.set_max_requests_per_connection() only has an effect "
@@ -695,6 +709,10 @@ class Cluster(object):
The default is 2 for :attr:`~HostDistance.LOCAL` and 1 for The default is 2 for :attr:`~HostDistance.LOCAL` and 1 for
:attr:`~HostDistance.REMOTE`. :attr:`~HostDistance.REMOTE`.
Protocol version 1 and 2 are limited in the number of concurrent
requests they can send per connection. The driver implements connection
pooling to support higher levels of concurrency.
If :attr:`~.Cluster.protocol_version` is set to 3 or higher, this If :attr:`~.Cluster.protocol_version` is set to 3 or higher, this
is not supported (there is always one connection per host, unless is not supported (there is always one connection per host, unless
the host is remote and :attr:`connect_to_remote_hosts` is :const:`False`) the host is remote and :attr:`connect_to_remote_hosts` is :const:`False`)

8
docs/api/cassandra/cluster.rst
View File

@@ -57,6 +57,14 @@
.. automethod:: unregister_listener .. automethod:: unregister_listener
.. automethod:: set_max_requests_per_connection
.. automethod:: get_max_requests_per_connection
.. automethod:: set_min_requests_per_connection
.. automethod:: get_min_requests_per_connection
.. automethod:: get_core_connections_per_host .. automethod:: get_core_connections_per_host
.. automethod:: set_core_connections_per_host .. automethod:: set_core_connections_per_host