30199552ac
The existing `download_source` implementation optimizes performance by keeping the connection to S3 open and draining data directly from the socket. While this eliminates the overhead (60-100ms) of repeatedly establishing new connections, it leads to rapid exhaustion of client- side connections. On a single shard, two `mx_readers` for load and stream are enough to trigger this issue. Since each client typically holds two connections, readers keeping index and data sources open can cause deadlocks where processes stall due to unavailable connections. Introduce `chunked_download_source`, a new S3 download method built on `download_source`, to dynamically manage connections: - Buffers data in 5MiB chunks using a producer-consumer model - Closes connections once buffers reach capacity, returning them to the pool for other clients - Uses a filling fiber that resumes fetching once buffers are consumed from the queue Performance remains comparable to `download_source`, achieving 95MiB/s for sequential 1GiB downloads from S3. However, preloading large chunks may cause read amplification. Fixes: https://github.com/scylladb/scylladb/issues/23785 Closes scylladb/scylladb#23880
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.