public void close() {
if (shuttingDown.getAndSet(true)) {
return;
}
mutex.lock();
try {
while (backgroundCompaction != null) {
backgroundCondition.awaitUninterruptibly();
}
} finally {
mutex.unlock();
}
compactionExecutor.shutdown();
try {
compactionExecutor.awaitTermination(1, TimeUnit.DAYS);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
try {
versions.destroy();
} catch (IOException ignored) {
}
try {
log.close();
} catch (IOException ignored) {
}
tableCache.close();
dbLock.release();
}
private void makeRoomForWrite(boolean force) {
Preconditions.checkState(mutex.isHeldByCurrentThread());
boolean allowDelay = !force;
while (true) {
// todo background processing system need work
// if (!bg_error_.ok()) {
// // Yield previous error
// s = bg_error_;
// break;
// } else
if (allowDelay && versions.numberOfFilesInLevel(0) > L0_SLOWDOWN_WRITES_TRIGGER) {
// We are getting close to hitting a hard limit on the number of
// L0 files. Rather than delaying a single write by several
// seconds when we hit the hard limit, start delaying each
// individual write by 1ms to reduce latency variance. Also,
// this delay hands over some CPU to the compaction thread in
// case it is sharing the same core as the writer.
try {
mutex.unlock();
Thread.sleep(1);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
throw new RuntimeException(e);
} finally {
mutex.lock();
}
// Do not delay a single write more than once
allowDelay = false;
} else if (!force && memTable.approximateMemoryUsage() <= options.writeBufferSize()) {
// There is room in current memtable
break;
} else if (immutableMemTable != null) {
// We have filled up the current memtable, but the previous
// one is still being compacted, so we wait.
backgroundCondition.awaitUninterruptibly();
} else if (versions.numberOfFilesInLevel(0) >= L0_STOP_WRITES_TRIGGER) {
// There are too many level-0 files.
// Log(options_.info_log, "waiting...\n");
backgroundCondition.awaitUninterruptibly();
} else {
// Attempt to switch to a new memtable and trigger compaction of old
Preconditions.checkState(versions.getPrevLogNumber() == 0);
// close the existing log
try {
log.close();
} catch (IOException e) {
throw new RuntimeException("Unable to close log file " + log.getFile(), e);
}
// open a new log
long logNumber = versions.getNextFileNumber();
try {
this.log =
Logs.createLogWriter(
new File(databaseDir, Filename.logFileName(logNumber)), logNumber);
} catch (IOException e) {
throw new RuntimeException(
"Unable to open new log file "
+ new File(databaseDir, Filename.logFileName(logNumber)).getAbsoluteFile(),
e);
}
// create a new mem table
immutableMemTable = memTable;
memTable = new MemTable(internalKeyComparator);
// Do not force another compaction there is space available
force = false;
maybeScheduleCompaction();
}
}
}