Amazon Neptune Database implemented an online index rebuild feature enabling database teams to compact fragmented indexes and recover unused storage space without interrupting read or write operations. Fragmentation from data mutations can cause inflated storage usage and degrade query efficiency on Gremlin, openCypher, or SPARQL workloads at scale.
The rebuild process supports tuning concurrency and buffer sizes to balance speed versus workload impact, with safeguards against storage exhaustion. Administrators can selectively target index types, facilitating efficient maintenance and performance tuning. This capability launched in engine release 1.5.0.0 on provisioned writer instances across all supported Regions.
Source & further reading
Amazon Neptune now supports online index rebuild to reclaim storage ↗Source published 2026-10-27. This report was prepared with AI assistance from the linked primary-source material. Claims and limitations should be checked against the original announcement or research.