/** Create or open log files used by this log. */
private void createOrOpenLogFiles() throws ChangelogException {
exclusiveLock.lock();
try {
createRootDirIfNotExists();
openHeadLogFile();
for (final File file : getReadOnlyLogFiles()) {
openReadOnlyLogFile(file);
}
isClosed = false;
} catch (ChangelogException e) {
// ensure all log files opened at this point are closed
close();
throw new ChangelogException(
ERR_CHANGELOG_UNABLE_TO_INITIALIZE_LOG.get(logPath.getPath()), e);
} finally {
exclusiveLock.unlock();
}
}
/**
* Rotate the head log file to a read-only log file, and open a new empty head log file to write
* in.
*
* <p>All cursors opened on this log are temporarily disabled (closing underlying resources) and
* then re-open with their previous state.
*/
private void rotateHeadLogFile() throws ChangelogException {
// Temporarily disable cursors opened on head, saving their state
final List<Pair<AbortableLogCursor<K, V>, CursorState<K, V>>> cursorsOnHead =
disableOpenedCursorsOnHead();
final LogFile<K, V> headLogFile = getHeadLogFile();
final File readOnlyLogFile = new File(logPath, generateReadOnlyFileName(headLogFile));
headLogFile.close();
renameHeadLogFileTo(readOnlyLogFile);
openHeadLogFile();
openReadOnlyLogFile(readOnlyLogFile);
// Re-enable cursors previously opened on head, with the saved state
updateOpenedCursorsOnHeadAfterRotation(cursorsOnHead);
// Notify even if time-based rotation is not enabled, as it could be enabled at any time
replicationEnv.notifyLogFileRotation(this);
lastRotationTime = timeService.now();
}
/**
* 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();
}
}