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Databases & messaging · #cassandra
Goal Determine how the backpressure semantics introduced in DataStax Java Driver 4.x alter the detection and handling of connection‑pool exhaustion compared with the 3.x series. Constraints and Uncertainty Configuration keys, metric names, and default pool sizes differ between the two major driver versions. Server‑side overload, hot partitions, and GC pauses
Two ways to absorb bursts into a fixed pool The DataStax Java Driver 4 sizes each node's connection pool statically at session start via PoolingOptions — maxConnectionsPerHost together with maxRequestsPerConnection . Nothing resizes the pool in response to load, so bursts that exceed the configured in-flight capacity end up rejected or queued depending on th
Goal Determine whether it is safe to manually align the system.schema.version table with the running Cassandra binary after an interrupted upgrade, or whether a pre‑upgrade snapshot must be restored before retrying the upgrade. Constraints include verifying binary compatibility, avoiding schema corruption, and ensuring that subsequent nodetool upgradesstable
Goal: prevent accidental public access to the Apache Cassandra native transport port 9042 in a self-managed cluster running Cassandra 4.x. By default, AllowAllAuthenticator is active and the transport can bind to 0.0.0.0, so an exposed interface allows unauthenticated CQL access. Two documented controls address this: enabling PasswordAuthenticator in cassand
Context In a single‑node test environment, the default max_hint_window_in_ms of 60 seconds is often sufficient to recover from brief outages. However, in a production cluster spanning multiple data centers, network partitions can last longer than this window, causing hints to expire before they are replayed. Trade‑Off Enabling hinted handoff trades increased
Implementing a least-privilege security model in Apache Cassandra typically involves configuring the PasswordAuthenticator and utilizing GRANT / REVOKE commands to restrict access to specific keyspaces and tables. While Cassandra supports granular Role-Based Access Control (RBAC), the internal authentication provider does not natively support automated crede
Goal Determine whether a Cassandra node that failed during a major-version upgrade can be returned to the previous Cassandra version without data loss, assuming the new binaries started and wrote system tables or SSTables before the failure. Constraints Cassandra on-disk formats can change incompatibly between major releases, and restarting older binaries ov
Goal Determine whether a PagingState token obtained from a query can be safely reused after the originating CQL session is closed. Constraints and uncertainty The Cassandra 4.0 documentation describes PagingState as an opaque token for server‑side pagination but does not specify its lifecycle relative to session termination. Reusing a token across sessions m
Goal Decide whether a write can be safely retried after the Cassandra coordinator returns a timeout, when replicas may still be applying the mutation. Constraints When read_request_timeout_in_ms or request_timeout_in_ms expires, the coordinator replies to the client without sending an abort to replicas. The native protocol does not carry a distributed cancel