Was this page helpful?
ScyllaDB Python Driver is available under the Apache v2 License. ScyllaDB Python Driver is a fork of DataStax Python Driver. See Copyright here.
Caution
You're viewing documentation for an unstable version of Scylla Python Driver. Switch to the latest stable version.
Connectivity¶
The driver starts with one or more contact points, discovers the cluster topology, and opens connections to the nodes it needs. The application network must provide a usable path to every discovered node that the load-balancing configuration may use, either directly or through Client Routes. See Getting Started for basic contact-point and session setup.
Authentication and TLS configuration are covered in Security. For ScyllaDB Cloud, see ScyllaDB Cloud.
Choose the connection model that matches the network:
Model |
Use when |
Driver configuration |
|---|---|---|
Direct connectivity |
The application can route to every node address advertised by the cluster, including through VPC peering or another routed private network. |
Regular |
Client Routes |
Nodes are reached through per-node proxy endpoints and their advertised addresses are not directly reachable. |
Control-connection fallback¶
ControlConnectionQueryFallback offers Fallback,
which uses the shared control connection when no node pool is usable, and
SkipPoolCreation, which always uses it for application queries. Both modes
bind fallback queries to one keyspace at a time.
An explicit USE statement or set_keyspace()
can change that binding only when its Session is the sole fallback user. Another
Session using the control connection causes the change to fail. Queries already
in flight from the same Session may execute under either keyspace; wait for
those queries to finish before sending USE when their keyspace matters.
Another USE fails while an explicit keyspace change is pending. If the
driver is still selecting the Session’s initial keyspace, an explicit USE
waits for that setup to finish.
An uncertain USE result, such as a client timeout, closes the shared
control connection so a later query cannot inherit an unknown keyspace state.
Pooled keyspace changes¶
With node pools, the driver applies a successful USE to the Session’s
other connections. If any connection rejects that change, the calling USE
fails. The driver does not automatically retry the rejected change or replace
that connection.
The failure does not roll back changes that already succeeded:
Session.keyspace and some connections may already use the new keyspace.
Connections still using the old keyspace are not used for ordinary queries.
After correcting the cause of the rejection, issue USE again or create a
new Session before sending unqualified queries.
Contents¶
- Direct Connectivity (VPC Peering)
Connect directly to every cluster node through VPC peering or another routed network.
- Client Routes (Private Networking)
Connect through AWS PrivateLink, GCP Private Service Connect, or a similar per-node proxy setup.