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shivaspeaks merged 3 commits into from
May 14, 2026
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xds: Disable Priority LB child policy retention cache #12806

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faab2be
xds: Disable Priority LB child policy retention cache
shivaspeaks May 13, 2026
0ca6c99
resolve comments
shivaspeaks May 13, 2026
6787fb8
refactor lines
shivaspeaks May 14, 2026
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10 changes: 9 additions & 1 deletion xds/src/main/java/io/grpc/xds/PriorityLoadBalancer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,7 @@
import io.grpc.Status;
import io.grpc.SynchronizationContext;
import io.grpc.SynchronizationContext.ScheduledHandle;
import io.grpc.internal.GrpcUtil;
import io.grpc.util.ForwardingLoadBalancerHelper;
import io.grpc.util.GracefulSwitchLoadBalancer;
import io.grpc.xds.PriorityLoadBalancerProvider.PriorityLbConfig;
Expand Down Expand Up @@ -73,6 +74,8 @@ final class PriorityLoadBalancer extends LoadBalancer {
private SubchannelPicker currentPicker;
// Set to true if currently in the process of handling resolved addresses.
private boolean handlingResolvedAddresses;
static boolean enablePriorityLbChildPolicyCache =
GrpcUtil.getFlag("GRPC_EXPERIMENTAL_ENABLE_PRIORITY_LB_CHILD_POLICY_CACHE", false);

PriorityLoadBalancer(Helper helper) {
this.helper = checkNotNull(helper, "helper");
Expand All @@ -98,7 +101,12 @@ public Status acceptResolvedAddresses(ResolvedAddresses resolvedAddresses) {
if (!prioritySet.contains(priority)) {
ChildLbState childLbState = children.get(priority);
if (childLbState != null) {
childLbState.deactivate();
if (enablePriorityLbChildPolicyCache) {
childLbState.deactivate();
} else {
childLbState.tearDown();
children.remove(priority);
}
}
}
}
Expand Down
179 changes: 141 additions & 38 deletions xds/src/test/java/io/grpc/xds/PriorityLoadBalancerTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -149,6 +149,106 @@ public void tearDown() {

@Test
public void acceptResolvedAddresses() {
boolean originalFlagVal = PriorityLoadBalancer.enablePriorityLbChildPolicyCache;
PriorityLoadBalancer.enablePriorityLbChildPolicyCache = true;
try {
SocketAddress socketAddress = new InetSocketAddress(8080);
EquivalentAddressGroup eag = new EquivalentAddressGroup(socketAddress);
eag = AddressFilter.setPathFilter(eag, ImmutableList.of("p1"));
List<EquivalentAddressGroup> addresses = ImmutableList.of(eag);
Attributes attributes =
Attributes.newBuilder().set(Attributes.Key.create("fakeKey"), "fakeValue").build();
Object fooConfig0 = new Object();
PriorityChildConfig priorityChildConfig0 =
new PriorityChildConfig(newChildConfig(fooLbProvider, fooConfig0), true);
Object barConfig0 = new Object();
PriorityChildConfig priorityChildConfig1 =
new PriorityChildConfig(newChildConfig(barLbProvider, barConfig0), true);
Object fooConfig1 = new Object();
PriorityChildConfig priorityChildConfig2 =
new PriorityChildConfig(newChildConfig(fooLbProvider, fooConfig1), true);
PriorityLbConfig priorityLbConfig =
new PriorityLbConfig(
ImmutableMap.of("p0", priorityChildConfig0, "p1", priorityChildConfig1,
"p2", priorityChildConfig2),
ImmutableList.of("p0", "p1", "p2"));
Status status = priorityLb.acceptResolvedAddresses(
ResolvedAddresses.newBuilder()
.setAddresses(addresses)
.setAttributes(attributes)
.setLoadBalancingPolicyConfig(priorityLbConfig)
.build());
assertThat(status.getCode()).isEqualTo(Status.Code.OK);
assertThat(fooBalancers).hasSize(1);
assertThat(barBalancers).isEmpty();
LoadBalancer fooBalancer0 = Iterables.getOnlyElement(fooBalancers);
verify(fooBalancer0).acceptResolvedAddresses(resolvedAddressesCaptor.capture());
ResolvedAddresses addressesReceived = resolvedAddressesCaptor.getValue();
assertThat(addressesReceived.getAddresses()).isEmpty();
assertThat(addressesReceived.getAttributes()).isEqualTo(attributes);
assertThat(addressesReceived.getLoadBalancingPolicyConfig()).isEqualTo(fooConfig0);

// Fail over to p1.
fakeClock.forwardTime(10, TimeUnit.SECONDS);
assertThat(fooBalancers).hasSize(1);
assertThat(barBalancers).hasSize(1);
LoadBalancer barBalancer0 = Iterables.getOnlyElement(barBalancers);
verify(barBalancer0).acceptResolvedAddresses(resolvedAddressesCaptor.capture());
addressesReceived = resolvedAddressesCaptor.getValue();
assertThat(Iterables.getOnlyElement(addressesReceived.getAddresses()).getAddresses())
.containsExactly(socketAddress);
assertThat(addressesReceived.getAttributes()).isEqualTo(attributes);
assertThat(addressesReceived.getLoadBalancingPolicyConfig()).isEqualTo(barConfig0);

// Fail over to p2.
fakeClock.forwardTime(10, TimeUnit.SECONDS);
assertThat(fooBalancers).hasSize(2);
assertThat(barBalancers).hasSize(1);
LoadBalancer fooBalancer1 = Iterables.getLast(fooBalancers);
verify(fooBalancer1).acceptResolvedAddresses(resolvedAddressesCaptor.capture());
addressesReceived = resolvedAddressesCaptor.getValue();
assertThat(addressesReceived.getAddresses()).isEmpty();
assertThat(addressesReceived.getAttributes()).isEqualTo(attributes);
assertThat(addressesReceived.getLoadBalancingPolicyConfig()).isEqualTo(fooConfig1);

// New update: p0 and p2 deleted; p1 config changed.
SocketAddress newSocketAddress = new InetSocketAddress(8081);
EquivalentAddressGroup newEag = new EquivalentAddressGroup(newSocketAddress);
newEag = AddressFilter.setPathFilter(newEag, ImmutableList.of("p1"));
List<EquivalentAddressGroup> newAddresses = ImmutableList.of(newEag);
Object newBarConfig = new Object();
PriorityLbConfig newPriorityLbConfig =
new PriorityLbConfig(
ImmutableMap.of("p1",
new PriorityChildConfig(newChildConfig(barLbProvider, newBarConfig), true)),
ImmutableList.of("p1"));
status = priorityLb.acceptResolvedAddresses(
ResolvedAddresses.newBuilder()
.setAddresses(newAddresses)
.setLoadBalancingPolicyConfig(newPriorityLbConfig)
.build());
assertThat(status.getCode()).isEqualTo(Status.Code.OK);
assertThat(fooBalancers).hasSize(2);
assertThat(barBalancers).hasSize(1);
verify(barBalancer0, times(2)).acceptResolvedAddresses(resolvedAddressesCaptor.capture());
addressesReceived = resolvedAddressesCaptor.getValue();
assertThat(Iterables.getOnlyElement(addressesReceived.getAddresses()).getAddresses())
.containsExactly(newSocketAddress);
assertThat(addressesReceived.getAttributes()).isEqualTo(Attributes.EMPTY);
assertThat(addressesReceived.getLoadBalancingPolicyConfig()).isEqualTo(newBarConfig);
verify(fooBalancer0, never()).shutdown();
verify(fooBalancer1, never()).shutdown();
fakeClock.forwardTime(15, TimeUnit.MINUTES);
verify(fooBalancer0).shutdown();
verify(fooBalancer1).shutdown();
verify(barBalancer0, never()).shutdown();
} finally {
PriorityLoadBalancer.enablePriorityLbChildPolicyCache = originalFlagVal;
}
}

@Test
public void acceptResolvedAddresses_cacheDisabled() {
SocketAddress socketAddress = new InetSocketAddress(8080);
EquivalentAddressGroup eag = new EquivalentAddressGroup(socketAddress);
eag = AddressFilter.setPathFilter(eag, ImmutableList.of("p1"));
Expand Down Expand Up @@ -233,9 +333,6 @@ public void acceptResolvedAddresses() {
.containsExactly(newSocketAddress);
assertThat(addressesReceived.getAttributes()).isEqualTo(Attributes.EMPTY);
assertThat(addressesReceived.getLoadBalancingPolicyConfig()).isEqualTo(newBarConfig);
verify(fooBalancer0, never()).shutdown();
verify(fooBalancer1, never()).shutdown();
fakeClock.forwardTime(15, TimeUnit.MINUTES);
verify(fooBalancer0).shutdown();
verify(fooBalancer1).shutdown();
verify(barBalancer0, never()).shutdown();
Expand Down Expand Up @@ -297,41 +394,47 @@ public void acceptResolvedAddresses_propagatesChildFailures() {

@Test
public void handleNameResolutionError() {
Object fooConfig0 = new Object();
PriorityChildConfig priorityChildConfig0 =
new PriorityChildConfig(newChildConfig(fooLbProvider, fooConfig0), true);
Object fooConfig1 = new Object();
PriorityChildConfig priorityChildConfig1 =
new PriorityChildConfig(newChildConfig(fooLbProvider, fooConfig1), true);

PriorityLbConfig priorityLbConfig =
new PriorityLbConfig(ImmutableMap.of("p0", priorityChildConfig0), ImmutableList.of("p0"));
priorityLb.acceptResolvedAddresses(
ResolvedAddresses.newBuilder()
.setAddresses(ImmutableList.<EquivalentAddressGroup>of())
.setLoadBalancingPolicyConfig(priorityLbConfig)
.build());
LoadBalancer fooLb0 = Iterables.getOnlyElement(fooBalancers);
Status status = Status.DATA_LOSS.withDescription("fake error");
priorityLb.handleNameResolutionError(status);
verify(fooLb0).handleNameResolutionError(status);

priorityLbConfig =
new PriorityLbConfig(ImmutableMap.of("p1", priorityChildConfig1), ImmutableList.of("p1"));
priorityLb.acceptResolvedAddresses(
ResolvedAddresses.newBuilder()
.setAddresses(ImmutableList.<EquivalentAddressGroup>of())
.setLoadBalancingPolicyConfig(priorityLbConfig)
.build());
assertThat(fooBalancers).hasSize(2);
LoadBalancer fooLb1 = Iterables.getLast(fooBalancers);
status = Status.UNAVAILABLE.withDescription("fake error");
priorityLb.handleNameResolutionError(status);
// fooLb0 is deactivated but not yet deleted. However, because it is delisted by the latest
// address update, name resolution error will not be propagated to it.
verify(fooLb0, never()).shutdown();
verify(fooLb0, never()).handleNameResolutionError(status);
verify(fooLb1).handleNameResolutionError(status);
boolean originalFlagVal = PriorityLoadBalancer.enablePriorityLbChildPolicyCache;
PriorityLoadBalancer.enablePriorityLbChildPolicyCache = true;
try {
Object fooConfig0 = new Object();
PriorityChildConfig priorityChildConfig0 =
new PriorityChildConfig(newChildConfig(fooLbProvider, fooConfig0), true);
Object fooConfig1 = new Object();
PriorityChildConfig priorityChildConfig1 =
new PriorityChildConfig(newChildConfig(fooLbProvider, fooConfig1), true);

PriorityLbConfig priorityLbConfig =
new PriorityLbConfig(ImmutableMap.of("p0", priorityChildConfig0), ImmutableList.of("p0"));
priorityLb.acceptResolvedAddresses(
ResolvedAddresses.newBuilder()
.setAddresses(ImmutableList.<EquivalentAddressGroup>of())
.setLoadBalancingPolicyConfig(priorityLbConfig)
.build());
LoadBalancer fooLb0 = Iterables.getOnlyElement(fooBalancers);
Status status = Status.DATA_LOSS.withDescription("fake error");
priorityLb.handleNameResolutionError(status);
verify(fooLb0).handleNameResolutionError(status);

priorityLbConfig =
new PriorityLbConfig(ImmutableMap.of("p1", priorityChildConfig1), ImmutableList.of("p1"));
priorityLb.acceptResolvedAddresses(
ResolvedAddresses.newBuilder()
.setAddresses(ImmutableList.<EquivalentAddressGroup>of())
.setLoadBalancingPolicyConfig(priorityLbConfig)
.build());
assertThat(fooBalancers).hasSize(2);
LoadBalancer fooLb1 = Iterables.getLast(fooBalancers);
status = Status.UNAVAILABLE.withDescription("fake error");
priorityLb.handleNameResolutionError(status);
// fooLb0 is deactivated but not yet deleted. However, because it is delisted by the latest
// address update, name resolution error will not be propagated to it.
verify(fooLb0, never()).shutdown();
verify(fooLb0, never()).handleNameResolutionError(status);
verify(fooLb1).handleNameResolutionError(status);
} finally {
PriorityLoadBalancer.enablePriorityLbChildPolicyCache = originalFlagVal;
}
}

@Test
Expand Down
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