Package org.elasticsearch.gateway
Class AsyncShardFetch<T extends BaseNodeResponse>
- java.lang.Object
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- org.elasticsearch.gateway.AsyncShardFetch<T>
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- All Implemented Interfaces:
java.io.Closeable
,java.lang.AutoCloseable
,Releasable
public abstract class AsyncShardFetch<T extends BaseNodeResponse> extends java.lang.Object implements Releasable
Allows to asynchronously fetch shard related data from other nodes for allocation, without blocking the cluster update thread.The async fetch logic maintains a map of which nodes are being fetched from in an async manner, and once the results are back, it makes sure to schedule a reroute to make sure those results will be taken into account.
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
AsyncShardFetch.FetchResult<T extends BaseNodeResponse>
The result of a fetch operation.static interface
AsyncShardFetch.Lister<NodesResponse extends BaseNodesResponse<NodeResponse>,NodeResponse extends BaseNodeResponse>
An action that lists the relevant shard data that needs to be fetched.
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Constructor Summary
Constructors Modifier Constructor Description protected
AsyncShardFetch(org.apache.logging.log4j.Logger logger, java.lang.String type, ShardId shardId, AsyncShardFetch.Lister<? extends BaseNodesResponse<T>,T> action)
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description void
close()
AsyncShardFetch.FetchResult<T>
fetchData(DiscoveryNodes nodes, java.util.Set<java.lang.String> ignoreNodes)
Fetches the data for the relevant shard.int
getNumberOfInFlightFetches()
Returns the number of async fetches that are currently ongoing.protected void
processAsyncFetch(java.util.List<T> responses, java.util.List<FailedNodeException> failures, long fetchingRound)
Called by the response handler of the async action to fetch data.protected abstract void
reroute(ShardId shardId, java.lang.String reason)
Implement this in order to scheduled another round that causes a call to fetch data.
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Field Detail
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logger
protected final org.apache.logging.log4j.Logger logger
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type
protected final java.lang.String type
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shardId
protected final ShardId shardId
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Constructor Detail
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AsyncShardFetch
protected AsyncShardFetch(org.apache.logging.log4j.Logger logger, java.lang.String type, ShardId shardId, AsyncShardFetch.Lister<? extends BaseNodesResponse<T>,T> action)
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Method Detail
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close
public void close()
- Specified by:
close
in interfacejava.lang.AutoCloseable
- Specified by:
close
in interfacejava.io.Closeable
- Specified by:
close
in interfaceReleasable
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getNumberOfInFlightFetches
public int getNumberOfInFlightFetches()
Returns the number of async fetches that are currently ongoing.
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fetchData
public AsyncShardFetch.FetchResult<T> fetchData(DiscoveryNodes nodes, java.util.Set<java.lang.String> ignoreNodes)
Fetches the data for the relevant shard. If there any ongoing async fetches going on, or new ones have been initiated by this call, the result will have no data.The ignoreNodes are nodes that are supposed to be ignored for this round, since fetching is async, we need to keep them around and make sure we add them back when all the responses are fetched and returned.
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processAsyncFetch
protected void processAsyncFetch(java.util.List<T> responses, java.util.List<FailedNodeException> failures, long fetchingRound)
Called by the response handler of the async action to fetch data. Verifies that its still working on the same cache generation, otherwise the results are discarded. It then goes and fills the relevant data for the shard (response + failures), issuing a reroute at the end of it to make sure there will be another round of allocations taking this new data into account.
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reroute
protected abstract void reroute(ShardId shardId, java.lang.String reason)
Implement this in order to scheduled another round that causes a call to fetch data.
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