org.apache.pulsar.broker.service.persistent.SystemTopic Maven / Gradle / Ivy

Go to download
/**
 * 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.pulsar.broker.service.persistent;

import static org.apache.pulsar.compaction.Compactor.COMPACTION_SUBSCRIPTION;
import java.util.concurrent.CompletableFuture;
import org.apache.bookkeeper.mledger.ManagedLedger;
import org.apache.pulsar.broker.PulsarServerException;
import org.apache.pulsar.broker.service.BrokerService;
import org.apache.pulsar.broker.service.BrokerServiceException;
import org.apache.pulsar.common.api.proto.CommandSubscribe;

public class SystemTopic extends PersistentTopic {

    public SystemTopic(String topic, ManagedLedger ledger, BrokerService brokerService)
            throws BrokerServiceException.NamingException, PulsarServerException {
        super(topic, ledger, brokerService);
    }

    @Override
    public boolean isSizeBacklogExceeded() {
        return false;
    }

    @Override
    public boolean isTimeBacklogExceeded() {
        return false;
    }

    @Override
    public boolean isSystemTopic() {
        return true;
    }

    @Override
    public void checkMessageExpiry() {
        // do nothing for system topic
    }

    @Override
    public void checkGC() {
        // do nothing for system topic
    }

    @Override
    public CompletableFuture checkReplication() {
        return CompletableFuture.completedFuture(null);
    }

    public CompletableFuture preCreateSubForCompactionIfNeeded() {
        if (!super.hasCompactionTriggered()) {
            // To pre-create the subscription for the compactor to avoid lost any data since we are using reader
            // for reading data from the __change_events topic, if no durable subscription on the topic,
            // the data might be lost. Since we are using the topic compaction on the __change_events topic
            // to reduce the topic policy cache recovery time,
            // so we can leverage the topic compaction cursor for retaining the data.
            return super.createSubscription(COMPACTION_SUBSCRIPTION,
                    CommandSubscribe.InitialPosition.Earliest, false)
                    .thenCompose(__ -> CompletableFuture.completedFuture(null));
        } else {
            return CompletableFuture.completedFuture(null);
        }
    }
}