Last week in scylladb.git master (issue #238; 2024-07-14)

This short report brings to light some interesting commits to scylladb.git master from the last week. Commits in the 407274e828…53a6ec05ed range are covered.

There were 55 non-merge commits from 19 authors in that period. Some notable commits:


There are now metrics keeping track of incoming hints, in addition to the existing metrics for outgoing hints.

A regression the the Lightweight Transaction (LWT) contention metric has been fixed. The regression would shop contentions increasing even when none were happening. While it’s just a metrics, it’s one of the more important ones for LWT users.

There is now a REST API for triggering a Raft group 0 read barrier. This is useful for making sure all nodes have caught up with the Raft leader and see the latest schema and topology.

In ScyllaDB writes have a server memory footprint even after an acknowledgement is returned to the client, in order to track writes to replica past the consistency level requirement. In one case, CL=ANY and all the target replicas DOWN, writes were kept even after all replicas acknowledged, increasing server memory load, and possibly preventing topology changes from making progress. This scenario can be generated internally when writing to a materialized view. We now clean up the internal structures immediately.

In rare cases, ScyllaDB might crash while inserting a mutation into memtable or cache. This is now fixed.

Keyspaces with tablets enabled will now reject tables with counter columns, as counters aren’t yet supported with tablets.

A bug in DESCRIBE SCHEMA when describing indexes on collection columns was fixed.

Changes to service levels are now reflected immediately after the change, rather than via a polling loop with a cycle time of 10 seconds.

A lock over the node tablet replica map was removed, as it was causing topology changes to be delayed.


See you in the next issue of last week in scylladb.git master!