modules/core/src/main/java/org/apache/ignite/internal/processors/cache/mvcc/MvccSnapshot.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.ignite.internal.processors.cache.mvcc;

import org.apache.ignite.plugin.extensions.communication.Message;

/**
 * MVCC snapshot which holds the following information:
 * - Current MVCC version which should be used for visibility checks
 * - List of active transactions which should not be visible to current transaction
 * - Cleanup version which is used to help vacuum process.
 */
public interface MvccSnapshot extends MvccVersion, Message {
    /**
     * @return Active transactions.
     */
    public MvccLongList activeTransactions();

    /**
     * @return Cleanup version (all smaller versions are safe to remove).
     */
    public long cleanupVersion();

    /**
     * @return Version without active transactions.
     */
    public MvccSnapshot withoutActiveTransactions();

    /**
     * Increments operation counter.
     */
    public void incrementOperationCounter();
}