/**
* Returns the key bounds for the provided log file.
*
* @return the pair of (lowest key, highest key) that correspond to records stored in the
* corresponding log file.
* @throws ChangelogException if an error occurs while retrieving the keys
*/
private Pair<K, K> getKeyBounds(final LogFile<K, V> logFile) throws ChangelogException {
try {
final String name = logFile.getFile().getName();
final String[] keys =
name.substring(0, name.length() - Log.LOG_FILE_SUFFIX.length())
.split(LOG_FILE_NAME_SEPARATOR);
return Pair.of(
recordParser.decodeKeyFromString(keys[0]), recordParser.decodeKeyFromString(keys[1]));
} catch (Exception e) {
throw new ChangelogException(
ERR_CHANGELOG_UNABLE_TO_RETRIEVE_KEY_BOUNDS_FROM_FILE.get(logFile.getFile().getPath()),
e);
}
}
/**
* Purge the log up to and excluding the provided key.
*
* @param purgeKey the key up to which purging must happen
* @return the oldest non purged record, or {@code null} if no record was purged
* @throws ChangelogException if a database problem occurs.
*/
public Record<K, V> purgeUpTo(final K purgeKey) throws ChangelogException {
exclusiveLock.lock();
try {
if (isClosed) {
return null;
}
final SortedMap<K, LogFile<K, V>> logFilesToPurge = logFiles.headMap(purgeKey);
if (logFilesToPurge.isEmpty()) {
return null;
}
final List<String> undeletableFiles = new ArrayList<>();
final Iterator<LogFile<K, V>> entriesToPurge = logFilesToPurge.values().iterator();
while (entriesToPurge.hasNext()) {
final LogFile<K, V> logFile = entriesToPurge.next();
try {
abortCursorsOpenOnLogFile(logFile);
logFile.close();
logFile.delete();
entriesToPurge.remove();
} catch (ChangelogException e) {
// The deletion of log file on file system has failed
undeletableFiles.add(logFile.getFile().getPath());
}
}
if (!undeletableFiles.isEmpty()) {
throw new ChangelogException(
ERR_CHANGELOG_UNABLE_TO_DELETE_LOG_FILE_WHILE_PURGING.get(
Utils.joinAsString(", ", undeletableFiles)));
}
return getOldestRecord();
} finally {
exclusiveLock.unlock();
}
}
/**
* Empties the log, discarding all records it contains.
*
* <p>All cursors open on the log are aborted.
*
* @throws ChangelogException If cursors are opened on this log, or if a problem occurs during
* clearing operation.
*/
public void clear() throws ChangelogException {
exclusiveLock.lock();
try {
if (isClosed) {
return;
}
if (!openCursors.isEmpty()) {
// All open cursors are aborted, which means the change number indexer thread
// should manage AbortedChangelogCursorException specifically to avoid being
// stopped
abortAllOpenCursors();
}
// delete all log files
final List<String> undeletableFiles = new ArrayList<>();
for (LogFile<K, V> logFile : logFiles.values()) {
try {
logFile.close();
logFile.delete();
} catch (ChangelogException e) {
undeletableFiles.add(logFile.getFile().getPath());
}
}
if (!undeletableFiles.isEmpty()) {
throw new ChangelogException(
ERR_CHANGELOG_UNABLE_TO_DELETE_LOG_FILE.get(
Utils.joinAsString(", ", undeletableFiles)));
}
logFiles.clear();
// recreate an empty head log file
openHeadLogFile();
} catch (Exception e) {
throw new ChangelogException(
ERR_ERROR_CLEARING_DB.get(logPath.getPath(), stackTraceToSingleLineString(e)));
} finally {
exclusiveLock.unlock();
}
}
private boolean isHeadLogFile(final LogFile<K, V> logFile) {
return logFile.getFile().getName().equals(Log.HEAD_LOG_FILE_NAME);
}
/**
* Dump this log as a text files, intended for debugging purpose only.
*
* @param dumpDirectory Directory that will contains log files with text format and ".txt"
* extensions
* @throws ChangelogException If an error occurs during dump
*/
void dumpAsTextFile(File dumpDirectory) throws ChangelogException {
for (LogFile<K, V> logFile : logFiles.values()) {
logFile.dumpAsTextFile(new File(dumpDirectory, logFile.getFile().getName() + ".txt"));
}
}
@Override
public String toString() {
return String.format(
"Cursor on log : %s, current log file: %s, current cursor: %s",
log.logPath, currentLogFile.getFile().getName(), currentCursor);
}