Package org.apache.pinot.broker.routing.instanceselector

Interface InstanceSelector

All Known Implementing Classes:

BalancedInstanceSelector, MultiStageReplicaGroupSelector, ReplicaGroupInstanceSelector, StrictReplicaGroupInstanceSelector

public interface InstanceSelector

The instance selector selects server instances to serve the query based on the selected segments.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	InstanceSelector.SelectionResult

Method Summary

Modifier and Type	Method	Description
void	init(Set<String> enabledInstances, org.apache.helix.model.IdealState idealState, org.apache.helix.model.ExternalView externalView, Set<String> onlineSegments)	Initializes the instance selector with the enabled instances, ideal state, external view and online segments (segments with ONLINE/CONSUMING instances in the ideal state and pre-selected by the SegmentPreSelector).
void	onAssignmentChange(org.apache.helix.model.IdealState idealState, org.apache.helix.model.ExternalView externalView, Set<String> onlineSegments)	Processes the segment assignment (ideal state or external view) change based on the given online segments (segments with ONLINE/CONSUMING instances in the ideal state and pre-selected by the SegmentPreSelector).
void	onInstancesChange(Set<String> enabledInstances, List<String> changedInstances)	Processes the instances change.
InstanceSelector.SelectionResult	select(org.apache.pinot.common.request.BrokerRequest brokerRequest, List<String> segments, long requestId)	Selects the server instances for the given segments queried by the given broker request, returns a map from segment to selected server instance hosting the segment and a set of unavailable segments (no enabled instance or all enabled instances are in ERROR state).

Method Detail

init

void init(Set<String> enabledInstances,
          org.apache.helix.model.IdealState idealState,
          org.apache.helix.model.ExternalView externalView,
          Set<String> onlineSegments)

Initializes the instance selector with the enabled instances, ideal state, external view and online segments (segments with ONLINE/CONSUMING instances in the ideal state and pre-selected by the SegmentPreSelector). Should be called only once before calling other methods.

onInstancesChange

void onInstancesChange(Set<String> enabledInstances,
                       List<String> changedInstances)

Processes the instances change. Changed instances are pre-computed based on the current and previous enabled instances only once on the caller side and passed to all the instance selectors.

onAssignmentChange

void onAssignmentChange(org.apache.helix.model.IdealState idealState,
                        org.apache.helix.model.ExternalView externalView,
                        Set<String> onlineSegments)

Processes the segment assignment (ideal state or external view) change based on the given online segments (segments with ONLINE/CONSUMING instances in the ideal state and pre-selected by the SegmentPreSelector).

select

InstanceSelector.SelectionResult select(org.apache.pinot.common.request.BrokerRequest brokerRequest,
                                        List<String> segments,
                                        long requestId)

Selects the server instances for the given segments queried by the given broker request, returns a map from segment to selected server instance hosting the segment and a set of unavailable segments (no enabled instance or all enabled instances are in ERROR state).

Parameters:

brokerRequest - BrokerRequest for the query

segments - segments for which instance needs to be selected

requestId - requestId generated by the Broker for a query

Returns:

instance of SelectionResult which describes the instance to pick for a given segment