This release fixes a lot of issues with the cluster and improves cluster stability and reliability. Primary shards get elected and promoted from replicas when there is quorum and at least 5 minutes (by default) have passed since the primary shard’s node has been seen (this happens only for shards being actively accessed).

Files are now quarantined instead of deleted; this can happen when WAL gets corrupted, a stalled replica database is detected (not marked as replica but with a copy of the database), etc.

Changed

• BREAKING: Clustering: Added primary shard promotions
• BREAKING: Updated xapian-core to latest 1.5 (git@db790e9e12bb9b3ebeaf916ac0acdea9a7ab0dd1)
• Python client updated
• Quarantine (invalid) WAL and database files/directories when appropriate
• Only nodes marked as primary for shards get the replica, others simply erase (or quarantine) stalled databases.
• Unused server sockets are now fully closed during shutdown

Fixed

• BREAKING: Clustering: Increased overall cluster stability
• Remote protocol: Race conditions for some used database objects after checkin
• Refactored node shutdown process
• Schemas LRU properly detect changes to schemas now checking only inside “schema” and “description”
• WAL had a bug which could lead to skipped slots (it now checks revision before writing lines and recovers after errors)
• Many solo mode (and CLUSTERING=off) fixes.