Package org.opensearch.index

Class ShardIndexingPressureStore

java.lang.Object
org.opensearch.index.ShardIndexingPressureStore
public class ShardIndexingPressureStore
extends java.lang.Object
Shard indexing pressure store acts as a central repository for all the shard-level tracker objects currently being used at the Node level, for tracking indexing pressure requests. Store manages the tracker lifecycle, from creation, access, until it is evicted to be collected. Trackers are maintained at two levels for access simplicity and better memory management: 1. shardIndexingPressureHotStore : As the name suggests, it is hot store for tracker objects which are currently live i.e. being used to track an ongoing request. 2. shardIndexingPressureColdStore : This acts as the store for all the shard tracking objects which are currently being used by the framework. In addition to hot trackers, the recently used trackers which are although not currently live, but again can be used in near future, are also part of this store. To limit any memory implications, this store has an upper limit on the maximum number of trackers its can hold at any given time, which is a configurable dynamic setting. Tracking objects when created are part of both the hot store as well as cold store. However, once the object is no more live it is removed from the hot store. Objects in the cold store are evicted once the cold store reaches its maximum limit. Think of it like a periodic purge when upper limit is hit. During get if tracking object is not present in the hot store, a lookup is made into the cache store. If found, object is brought into the hot store again, until it remains active. If not present in the either store, a fresh object is instantiated and registered in both the stores for concurrent accesses. Note: The implementation of shardIndexingPressureColdStore methods is such that get, update and evict operations can be abstracted out to support any other strategy such as LRU, if discovered a need later.