When running Oak in a cluster, each write operation is expensive. After performing some stress-tests with a geo-distributed Mongo cluster, we've found out that updating property indexes is a large part of the overall traffic. Let's try to create a new property-local index, that will save the indexed data locally, without sharing it.
-there's a new property-local index type for which the data are saved in the local SegmentNodeStore instance created specifically for this purpose,
-local changes are indexed using a new editor, based on the PropertyIndexEditor,
-remote changes are extracted from the JournalEntries fetched in the background read operation and indexed as well,
-the new index type won't support uniqueness restriction.