/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.facebook.presto.execution.scheduler;
import com.facebook.presto.execution.RemoteTask;
import com.facebook.presto.metadata.Split;
import com.facebook.presto.spi.Node;
import com.facebook.presto.sql.planner.NodePartitionMap;
import java.util.List;
import java.util.Set;
public interface NodeSelector
{
void lockDownNodes();
List<Node> allNodes();
Node selectCurrentNode();
List<Node> selectRandomNodes(int limit);
/**
* Identifies the nodes for running the specified splits.
*
* @param splits the splits that need to be assigned to nodes
* @return a multimap from node to splits only for splits for which we could identify a node to schedule on.
* If we cannot find an assignment for a split, it is not included in the map. Also returns a future indicating when
* to reattempt scheduling of this batch of splits, if some of them could not be scheduled.
*/
SplitPlacementResult computeAssignments(Set<Split> splits, List<RemoteTask> existingTasks);
/**
* Identifies the nodes for running the specified splits based on a precomputed fixed partitioning.
*
* @param splits the splits that need to be assigned to nodes
* @return a multimap from node to splits only for splits for which we could identify a node with free space.
* If we cannot find an assignment for a split, it is not included in the map. Also returns a future indicating when
* to reattempt scheduling of this batch of splits, if some of them could not be scheduled.
*/
SplitPlacementResult computeAssignments(Set<Split> splits, List<RemoteTask> existingTasks, NodePartitionMap partitioning);
}