Last week in scylla.git master (issue #102; 2021-11-07)

[Avi Kivity]

This short report brings to light some interesting commits to scylla.git master from the last weeks. Commits in the 034f79cfb4..4950ce539 range are covered.

There were 56 non-merge commits from 10 authors in that period. Some notable commits:

In Time Window Compaction Strategy compactions, fully expired sstables will be compacted separately, since that can be done by just dropping them.

Scrub compaction, which re-sorts unsorted sstables, will now use memtables as a sorting mechanism instead of generating many small sstables.

Automatic I/O configuration during setup now supports AWS ARM instances.

Alternator, ScyllaDB's implementation of the DynamoDB API, now supports the ADD operation.

Usually a memtable is flushed into one sstable. In some cases, however, it can be flushed into several sstables. We now adjust the partition estimate for these sstables so the bloom filters allocated by these sstables will not occupy too much memory.

Size-tiered compaction strategy will prefer compactions with larger fan-in in order to improve efficiency. Moreover, once a compaction with large fan-in is started, compactions with lower fan-in will be delayed in order to improve overall write amplification.

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