org.apache.zookeeper.server.persistence.TxnLog Maven / Gradle / Ivy
/*
* 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.zookeeper.server.persistence;
import java.io.Closeable;
import java.io.IOException;
import org.apache.jute.Record;
import org.apache.zookeeper.server.ServerStats;
import org.apache.zookeeper.txn.TxnDigest;
import org.apache.zookeeper.txn.TxnHeader;
/**
* Interface for reading transaction logs.
*
*/
public interface TxnLog extends Closeable {
/**
* Setter for ServerStats to monitor fsync threshold exceed
* @param serverStats used to update fsyncThresholdExceedCount
*/
void setServerStats(ServerStats serverStats);
/**
* roll the current
* log being appended to
* @throws IOException
*/
void rollLog() throws IOException;
/**
* Append a request to the transaction log
* @param hdr the transaction header
* @param r the transaction itself
* @return true iff something appended, otw false
* @throws IOException
*/
boolean append(TxnHeader hdr, Record r) throws IOException;
/**
* Append a request to the transaction log with a digset
* @param hdr the transaction header
* @param r the transaction itself
* @param digest transaction digest
* returns true iff something appended, otw false
* @throws IOException
*/
boolean append(TxnHeader hdr, Record r, TxnDigest digest) throws IOException;
/**
* Start reading the transaction logs
* from a given zxid
* @param zxid
* @return returns an iterator to read the
* next transaction in the logs.
* @throws IOException
*/
TxnIterator read(long zxid) throws IOException;
/**
* the last zxid of the logged transactions.
* @return the last zxid of the logged transactions.
* @throws IOException
*/
long getLastLoggedZxid() throws IOException;
/**
* truncate the log to get in sync with the
* leader.
* @param zxid the zxid to truncate at.
* @throws IOException
*/
boolean truncate(long zxid) throws IOException;
/**
* the dbid for this transaction log.
* @return the dbid for this transaction log.
* @throws IOException
*/
long getDbId() throws IOException;
/**
* commit the transaction and make sure
* they are persisted
* @throws IOException
*/
void commit() throws IOException;
/**
*
* @return transaction log's elapsed sync time in milliseconds
*/
long getTxnLogSyncElapsedTime();
/**
* close the transactions logs
*/
void close() throws IOException;
/**
* Sets the total size of all log files
*/
void setTotalLogSize(long size);
/**
* Gets the total size of all log files
*/
long getTotalLogSize();
/**
* an iterating interface for reading
* transaction logs.
*/
interface TxnIterator extends Closeable {
/**
* return the transaction header.
* @return return the transaction header.
*/
TxnHeader getHeader();
/**
* return the transaction record.
* @return return the transaction record.
*/
Record getTxn();
/**
* @return the digest associated with the transaction.
*/
TxnDigest getDigest();
/**
* go to the next transaction record.
* @throws IOException
*/
boolean next() throws IOException;
/**
* close files and release the
* resources
* @throws IOException
*/
void close() throws IOException;
/**
* Get an estimated storage space used to store transaction records
* that will return by this iterator
* @throws IOException
*/
long getStorageSize() throws IOException;
}
}