/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 2002, 2011 Oracle and/or its affiliates. All rights reserved.
*
*/
package com.sleepycat.je.util;
import java.io.File;
import java.io.IOException;
import com.sleepycat.je.dbi.EnvironmentImpl;
import com.sleepycat.je.utilint.CmdUtil;
/**
* DbTruncateLog is a utility that lets the user truncate JE log starting at a
* specified file and offset to the last log file, inclusive. Generally used in
* replication systems for handling
* com.sleepycat.je.rep.RollbackProhibitedException, to permit the application
* to interject application specific handling. Should be used with caution.
* <p>
* The parameters for DbTruncateLog are provided through the
* RollbackProhibitedException instance, and the exception message. The goal is
* to truncate the JE log after a specified file number and file offset.
* DbTruncateLog will automatically delete all log entries after that specified
* log entry.
* <p>
* For example, suppose the JE log consists of these files:
* <pre>
* 00000002.jdb
* 0000000e.jdb
* 0000000f.jdb
* 00000010.jdb
* 00000012.jdb
* 0000001d.jdb
* 0000001e.jdb
* 0000001f.jdb
* </pre>
* And the log must be truncated at file 0x1d, offset 0x34567, users should use
* the following command:
* <ol>
* <li> DbTruncateLog -h <envDir> -f 0x1d -o 0x34567 </li>
* </ol>
*/
public class DbTruncateLog {
private long truncateFileNum = -1;
private long truncateOffset = -1;
private File envHome;
/**
* Usage:
* <pre>
* -h environmentDirectory
* -f file number. If hex, prefix with "0x"
* -o file offset byte. If hex, prefix with "0x"
* </pre>
* For example, to truncate a log to file 0xa, offset 0x1223:
* <pre>
* DbTruncateLog -h <environmentDir> -f 0xa -o 0x1223
* </pre>
*/
public static void main(String[] argv) {
try {
DbTruncateLog truncator = new DbTruncateLog();
truncator.parseArgs(argv);
truncator.truncateLog();
} catch (Exception e) {
e.printStackTrace();
usage();
System.exit(1);
}
}
public DbTruncateLog() {
}
private void parseArgs(String[] argv) {
int whichArg = 0;
boolean seenFile = false;
boolean seenOffset = false;
while (whichArg < argv.length) {
String nextArg = argv[whichArg];
if (nextArg.equals("-h")) {
whichArg++;
envHome = new File(CmdUtil.getArg(argv, whichArg));
} else if (nextArg.equals("-f")) {
whichArg++;
truncateFileNum =
CmdUtil.readLongNumber(CmdUtil.getArg(argv, whichArg));
seenFile = true;
} else if (nextArg.equals("-o")) {
whichArg++;
truncateOffset =
CmdUtil.readLongNumber(CmdUtil.getArg(argv, whichArg));
seenOffset = true;
} else {
throw new IllegalArgumentException
(nextArg + " is not a supported option.");
}
whichArg++;
}
if (envHome == null) {
usage();
System.exit(1);
}
if ((!seenFile) || (!seenOffset)) {
usage();
System.exit(1);
}
}
private void truncateLog()
throws IOException {
truncateLog(envHome, truncateFileNum, truncateOffset);
}
/**
* @hidden
* Truncate the JE log to the given file and offset. For unit tests.
*/
public void truncateLog(File env,
long truncFileNum,
long truncOffset)
throws IOException {
/* Make a read/write environment */
EnvironmentImpl envImpl =
CmdUtil.makeUtilityEnvironment(env, false);
/* Go through the file manager to get the JE file. Truncate. */
envImpl.getFileManager().truncateLog(truncFileNum, truncOffset);
envImpl.close();
}
private static void usage() {
System.out.println("Usage: " +
CmdUtil.getJavaCommand(DbTruncateLog.class));
System.out.println(" -h <environment home>");
System.out.println(" -f <file number, in hex>");
System.out.println(" -o <offset, in hex>");
System.out.println("JE log will be deleted starting from the " +
"position presented by the file number and " +
"offset to the end, inclusive.");
}
}