reddycharan commented on a change in pull request #1201: ISSUE #570: Entrylog
per ledger
URL: https://github.com/apache/bookkeeper/pull/1201#discussion_r171118157
##########
File path:
bookkeeper-server/src/main/java/org/apache/bookkeeper/bookie/EntryLogger.java
##########
@@ -588,93 +588,146 @@ public void accept(long ledgerId, long size) {
private long preallocatedLogId;
private Future<BufferedLogChannel> preallocation = null;
private ExecutorService allocatorExecutor;
- private final Object createEntryLogLock = new Object();
- private final Object createCompactionLogLock = new Object();
EntryLoggerAllocator(long logId) {
preallocatedLogId = logId;
allocatorExecutor = Executors.newSingleThreadExecutor();
}
- BufferedLogChannel createNewLog() throws IOException {
- synchronized (createEntryLogLock) {
- BufferedLogChannel bc;
- if (!entryLogPreAllocationEnabled){
- // create a new log directly
- bc = allocateNewLog();
- return bc;
- } else {
- // allocate directly to response request
- if (null == preallocation){
- bc = allocateNewLog();
+ synchronized long getPreallocatedLogId(){
+ return preallocatedLogId;
+ }
+
+ synchronized BufferedLogChannel createNewLog() throws IOException {
+ BufferedLogChannel bc;
+ if (!entryLogPreAllocationEnabled || null == preallocation) {
+ // initialization time to create a new log
+ bc = allocateNewLog();
+ } else {
+ // has a preallocated entry log
+ try {
+ /*
+ * both createNewLog and allocateNewLog are synchronized on
+ * EntryLoggerAllocator.this object. So it is possible that
+ * a thread calling createNewLog would attain the lock on
+ * this object and get to this point but preallocation
+ * Future is starving for lock on EntryLoggerAllocator.this
+ * to execute allocateNewLog. Here since we attained lock
+ * for this it means preallocation future must have either
+ * completed creating new log or still waiting for lock on
+ * this object to execute allocateNewLog method. So we
+ * should try to get result of the future without waiting.
+ * If it fails with TimeoutException then call
+ * allocateNewLog explicitly since we are holding the lock
+ * on this anyhow.
+ *
+ */
+ bc = preallocation.get(0, TimeUnit.MILLISECONDS);
+ } catch (ExecutionException ee) {
+ if (ee.getCause() instanceof IOException) {
+ throw (IOException) (ee.getCause());
} else {
- // has a preallocated entry log
- try {
- bc = preallocation.get();
- } catch (ExecutionException ee) {
- if (ee.getCause() instanceof IOException) {
- throw (IOException) (ee.getCause());
- } else {
- throw new IOException("Error to execute entry
log allocation.", ee);
- }
- } catch (CancellationException ce) {
- throw new IOException("Task to allocate a new
entry log is cancelled.", ce);
- } catch (InterruptedException ie) {
- throw new IOException("Intrrupted when waiting a
new entry log to be allocated.", ie);
- }
+ throw new IOException("Error to execute entry log
allocation.", ee);
}
- // preallocate a new log in background upon every call
- preallocation = allocatorExecutor.submit(() ->
allocateNewLog());
- return bc;
+ } catch (CancellationException ce) {
+ throw new IOException("Task to allocate a new entry log is
cancelled.", ce);
+ } catch (InterruptedException ie) {
+ throw new IOException("Intrrupted when waiting a new entry
log to be allocated.", ie);
+ } catch (TimeoutException e) {
+ LOG.debug("Received TimeoutException while trying to get
preallocation future result,"
+ + " which means that Future is waiting for
acquiring lock on EntryLoggerAllocator.this");
+ bc = allocateNewLog();
+ }
+ }
+ if (entryLogPreAllocationEnabled) {
+ /*
+ * We should submit new callable / create new instance of
future only if the previous preallocation is
+ * null or if it is done. This is needed because previous
preallocation has not completed its execution
+ * since it is waiting for lock on EntryLoggerAllocator.this.
+ */
+ if ((preallocation == null) || preallocation.isDone()) {
+ preallocation = allocatorExecutor.submit(new
Callable<BufferedLogChannel>() {
Review comment:
will do
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