software.amazon.jdbc.plugin.readwritesplitting.balancer

Class PerQueryBalancedReaderPolicy

java.lang.Object

software.amazon.jdbc.plugin.readwritesplitting.balancer.PerQueryBalancedReaderPolicy

All Implemented Interfaces:

LoadBalancingPolicy

public class PerQueryBalancedReaderPolicy
extends java.lang.Object
implements LoadBalancingPolicy

LoadBalancingPolicy that rotates readers per read query (query-level load balancing). When includeWriter is set, the writer is also an eligible target (role null). Rotation is confined by the plugin to an established read-only phase, so it never changes role.

Constructor Summary

Constructors

Constructor and Description
PerQueryBalancedReaderPolicy(boolean includeWriter, java.lang.String readerSelectorStrategy)

Method Summary

Modifier and Type	Method and Description
boolean	includesWriter()
boolean	isPerQuery() Whether this policy rotates readers per read query (query-level load balancing).
@Nullable HostSpec	pickReader(RwSplitContext ctx, java.util.List<HostSpec> candidates) Selects the reader target for this request, or null when no eligible target is available.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PerQueryBalancedReaderPolicy

public PerQueryBalancedReaderPolicy(boolean includeWriter,
                                    java.lang.String readerSelectorStrategy)

Method Detail

pickReader

public @Nullable HostSpec pickReader(RwSplitContext ctx,
                                     java.util.List<HostSpec> candidates)
                              throws java.sql.SQLException

Description copied from interface: LoadBalancingPolicy

Selects the reader target for this request, or null when no eligible target is available.

Specified by:

pickReader in interface LoadBalancingPolicy

Parameters:

ctx - the read/write splitting context

candidates - the eligible reader candidates

Returns:

the chosen reader host, or null if none is available

Throws:

java.sql.SQLException

isPerQuery

public boolean isPerQuery()

Description copied from interface: LoadBalancingPolicy

Whether this policy rotates readers per read query (query-level load balancing). When true, the plugin selects a fresh reader on each read-routing decision within an established read-only phase instead of reusing a single sticky reader.

Specified by:

isPerQuery in interface LoadBalancingPolicy

Returns:

true for per-query balancing; false (default) for a sticky reader

includesWriter

public boolean includesWriter()