MetaIdGenerator.java

// 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.doris.catalog;

import org.apache.doris.persist.EditLog;

import com.google.common.base.Preconditions;

// This new Id generator is just same as TransactionIdGenerator.
// But we can't just use TransactionIdGenerator to replace the old catalog's 'nextId' for compatibility reason.
// cause they are using different edit log operation type.
public class MetaIdGenerator {
    private static final int BATCH_ID_INTERVAL = 1000;

    private long nextId;
    private long batchEndId;

    private EditLog editLog;

    public MetaIdGenerator(long initValue) {
        nextId = initValue + 1;
        batchEndId = initValue;
    }

    public void setEditLog(EditLog editLog) {
        this.editLog = editLog;
    }

    // performance is more quickly
    public synchronized long getNextId() {
        if (nextId >= batchEndId) {
            batchEndId = batchEndId + BATCH_ID_INTERVAL;
            if (editLog != null) {
                // add this check just for unit test
                editLog.logSaveNextId(batchEndId);
            }
        }
        return nextId++;
    }

    public synchronized IdGeneratorBuffer getIdGeneratorBuffer(long bufferSize) {
        Preconditions.checkState(bufferSize > 0);
        IdGeneratorBuffer idGeneratorBuffer = new IdGeneratorBuffer(nextId, nextId + bufferSize - 1);
        nextId = nextId + bufferSize;
        if (nextId > batchEndId) {
            batchEndId = batchEndId + ((nextId - batchEndId) / BATCH_ID_INTERVAL + 1) * BATCH_ID_INTERVAL;
            Preconditions.checkState(nextId <= batchEndId);
            if (editLog != null) {
                editLog.logSaveNextId(batchEndId);
            }
        }
        return idGeneratorBuffer;
    }

    public synchronized void setId(long id) {
        if (id > batchEndId) {
            batchEndId = id;
            nextId = id;
        }
    }

    public synchronized long getBatchEndId() {
        return batchEndId;
    }

    public class IdGeneratorBuffer {
        private long nextId;
        private long batchEndId;

        private IdGeneratorBuffer(long nextId, long batchEndId) {
            this.nextId = nextId;
            this.batchEndId = batchEndId;
        }

        public long getNextId() {
            Preconditions.checkState(nextId <= batchEndId);
            return nextId++;
        }

        public long getBatchEndId() {
            return batchEndId;
        }
    }
}