org.apache.flink.runtime.state.StateUtil Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.flink.runtime.state;
import org.apache.flink.util.LambdaUtil;
import org.apache.flink.shaded.guava18.com.google.common.base.Joiner;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.concurrent.CancellationException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.RunnableFuture;
/** Helpers for {@link StateObject} related code. */
public class StateUtil {
private static final Logger LOG = LoggerFactory.getLogger(StateUtil.class);
private StateUtil() {
throw new AssertionError();
}
/**
* Returns the size of a state object.
*
* @param handle The handle to the retrieved state
*/
public static long getStateSize(StateObject handle) {
return handle == null ? 0 : handle.getStateSize();
}
/**
* Iterates through the passed state handles and calls discardState() on each handle that is not
* null. All occurring exceptions are suppressed and collected until the iteration is over and
* emitted as a single exception.
*
* @param handlesToDiscard State handles to discard. Passed iterable is allowed to deliver null
* values.
* @throws Exception exception that is a collection of all suppressed exceptions that were
* caught during iteration
*/
public static void bestEffortDiscardAllStateObjects(
Iterable handlesToDiscard) throws Exception {
LambdaUtil.applyToAllWhileSuppressingExceptions(
handlesToDiscard, StateObject::discardState);
}
/**
* Discards the given state future by first trying to cancel it. If this is not possible, then
* the state object contained in the future is calculated and afterwards discarded.
*
* @param stateFuture to be discarded
* @throws Exception if the discard operation failed
*/
public static void discardStateFuture(Future stateFuture)
throws Exception {
if (null != stateFuture) {
if (!stateFuture.cancel(true)) {
try {
// We attempt to get a result, in case the future completed before cancellation.
if (stateFuture instanceof RunnableFuture && !stateFuture.isDone()) {
((RunnableFuture) stateFuture).run();
}
StateObject stateObject = stateFuture.get();
if (null != stateObject) {
stateObject.discardState();
}
} catch (CancellationException | ExecutionException ex) {
LOG.debug(
"Cancelled execution of snapshot future runnable. Cancellation produced the following "
+ "exception, which is expected an can be ignored.",
ex);
}
}
}
}
/**
* Creates an {@link RuntimeException} that signals that an operation did not get the type of
* {@link StateObject} that was expected. This can mostly happen when a different {@link
* StateBackend} from the one that was used for taking a checkpoint/savepoint is used when
* restoring.
*/
@SuppressWarnings("unchecked")
public static RuntimeException unexpectedStateHandleException(
Class expectedStateHandleClass,
Class actualStateHandleClass) {
return unexpectedStateHandleException(
new Class[] {expectedStateHandleClass}, actualStateHandleClass);
}
/**
* Creates a {@link RuntimeException} that signals that an operation did not get the type of
* {@link StateObject} that was expected. This can mostly happen when a different {@link
* StateBackend} from the one that was used for taking a checkpoint/savepoint is used when
* restoring.
*/
public static RuntimeException unexpectedStateHandleException(
Class[] expectedStateHandleClasses,
Class actualStateHandleClass) {
return new IllegalStateException(
"Unexpected state handle type, expected one of: "
+ Joiner.on(", ").join(expectedStateHandleClasses)
+ ", but found: "
+ actualStateHandleClass
+ ". "
+ "This can mostly happen when a different StateBackend from the one "
+ "that was used for taking a checkpoint/savepoint is used when restoring.");
}
}