software.amazon.jdbc.plugin.readwritesplitting.balancer

Interface LoadBalancingPolicy

All Known Implementing Classes:

PerQueryBalancedReaderPolicy, StickyReaderPolicy

public interface LoadBalancingPolicy

Chooses the reader target for a request from a set of candidates ("sticky vs per-query balancing"). Implementations cover a sticky reader (reuse the cached reader) and per-query balancing (rotate readers within an established read-only phase).

Method Summary

Modifier and Type	Method and Description
default 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.

Method Detail

pickReader

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

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

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

default boolean isPerQuery()

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.

Returns:

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