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When a non-replica node handles a strongly consistent write, it must forward the request to a replica. If the closest replica is not the leader, the request gets redirected again, causing an extra roundtrip. Add a leader location cache in groups_manager, keyed by raft group_id. After a write request is forwarded, the CQL transport layer records the final node as the leader in the cache. Subsequent write requests from the same node for the same group are forwarded directly to the cached leader, eliminating the extra roundtrip. The cache is only used for writes. Reads can be served by any replica, so they skip the cache and use proximity-based routing instead. Cache entries are validated at use time: if the cached leader is no longer a replica (e.g. after tablet migration), the entry is evicted and the normal closest-replica path is taken. This prevents a scenario where two nodes keep redirecting to each other because both think that the other is the leader but actually both are non-replicas - such loop is broken as soon as the tablet maps are updated. On token_metadata updates, entries for groups that no longer exist (e.g. table dropped, tablet merged) are evicted. Entries for groups that still exist are kept — use-time validation handles staleness. An on_node_resolved callback is propagated through the redirect/bounce path so the transport layer can update the cache generically without coupling to the strong-consistency coordinator. The coordinator creates the callback only for writes (capturing the groups_manager and group_id) and attaches it to the bounce message; the transport layer invokes it once the final node is known, keeping the forwarding infrastructure subsystem-agnostic. We also add a test which verifies that after the initial redirect, following requests to the same node avoid the extra redirect and forward directly to the leader. Fixes: SCYLLADB-1064 Closes scylladb/scylladb#29392
Scylla in-source tests.
For details on how to run the tests, see docs/dev/testing.md
Shared C++ utils, libraries are in lib/, for Python - pylib/
alternator - Python tests which connect to a single server and use the DynamoDB API unit, boost, raft - unit tests in C++ cqlpy - Python tests which connect to a single server and use CQL topology* - tests that set up clusters and add/remove nodes cql - approval tests that use CQL and pre-recorded output rest_api - tests for Scylla REST API Port 9000 scylla-gdb - tests for scylla-gdb.py helper script nodetool - tests for C++ implementation of nodetool
If you can use an existing folder, consider adding your test to it. New folders should be used for new large categories/subsystems, or when the test environment is significantly different from some existing suite, e.g. you plan to start scylladb with different configuration, and you intend to add many tests and would like them to reuse an existing Scylla cluster (clusters can be reused for tests within the same folder).
To add a new folder, create a new directory, and then
copy & edit its suite.ini.