[Feature Request] Paginate snapshot indices status fetching
#16,985 建立於 2025年1月9日
描述
Is your feature request related to a problem? Please describe
Our customers depend on the snapshot status API to access information about snapshot indices, like store size, number of docs, etc. The TransportSnapshotStatusAction utilizes a single Generic thread to retrieve repository data, snapshot information, snapshot index metadata, and shard snapshot status if the specified snapshot(s) is not currently running. However, when the specified snapshot contains a large number of indices, the execution time for this action becomes significantly prolonged.
In one of the snapshot which has 15000+ shards, snapshot status fetching was taking 8min.
Describe the solution you'd like
Provide a new API (_snapshot/{repository}/{snapshot}/_list/indices) to paginate snapshot indices status like we did in #14258. The new API works only for indexes belonging to a specific snapshot. Since the order of indices in SnapshotInfo is settled, we can simply use from + size to paginate. If the specified snapshot is running, then the paginating parameters will have no effect.
Related component
Storage:Snapshots
Describe alternatives you've considered
Using the snapshot thread pool to parallelize indices snapshot status fetching. But the snapshot thread pool might be blocked on long running tasks. Moreover, the maximum number of threads in the snapshot thread pool is only 5, so the speedup effect may be limited
Additional context
No response