This short report brings to light some interesting commits to scylladb.git master from the two weeks. Commits in the 5d1840c4db4..88bb75b9229 range are covered.
There were 220 non-merge commits from 38 authors in that period. Some notable commits:
ScyllaDB can now query the full-text search index server for a BM25 ranking of search results.
The Transport-Layer Security (TLS) implementation now enables TLS 1.3 session tickets by default. This reduces CPU consumption during TLS handshakes.
Alternator, ScyllaDB’s implementation of the DynamoDB API, now avoids locking the topology during tablet scans, improving the speed of tablet migrations.
There are now warnings when an modification statement generates large partitions, large rows, or large cells.
The automatic vnode-to-tablets migration procedure now pre-splits into more tablets when necessary to balance the load well. After migration completes tablets will be merged so they cover uniform ranges in the token space.
Table restore, for tablet mode, is now driven by the topology coordinator. This makes it resilient to failures and improves observability.
The workload_type configuration of service levels is now exposed via a metric.
Data streaming on object storage is now implemented via a clone operation. This prevents moving the data via the compute node.
The algorithm for classifying connections as driver-internal or carrying user load was improved. A misclassification could result in user queries not receiving sufficient CPU time.
The reader_concurrency_semaphore mechanism is responsible for concurrency control on the read path. It also allocates memory for paged reads, allowing the next page to avoid an expensive seek. This memory allocation is now divided into a shared pool, allowing queries from different service levels to compete against each other for memory, and a private pool that is dedicated for each service level according to its shares. This allows good usage of memory when it is available, as well as guaranteeing important service levels the ability to make progress.
See you in the next issue of last week in scylladb.git master!