HBase 1.2.5 put 源码分析
1. HTable 调用 put(final Put put) 方法,本地有一个缓存，不是每一次put就会提交到服务器端.
@Override
public void put(final Put put) throws IOException {
getBufferedMutator().mutate(put);
if (autoFlush) {
flushCommits();
}
}2. 继续深入，发现拿到了一个管理缓存的类. BufferedMutatorImpl，可以看到这个类里面有本地缓存数据的大小
@VisibleForTesting
BufferedMutator getBufferedMutator() throws IOException {
if (mutator == null) {
this.mutator = (BufferedMutatorImpl) connection.getBufferedMutator(
new BufferedMutatorParams(tableName)
.pool(pool)
.writeBufferSize(connConfiguration.getWriteBufferSize())
.maxKeyValueSize(connConfiguration.getMaxKeyValueSize())
);
}
return mutator;
}
}3. 接下来看这个缓存类怎么将put 缓存着，还有什么时候提交给服务器端.即看 mutate(put) 方法.
a. Put 是Mutation的派生类，调用 mutate(List ms)
b. 将List ms 加入到本地的
final ConcurrentLinkedQueuewriteAsyncBuffer = new ConcurrentLinkedQueue (); 中，如果 缓存值大于配置的值，就会调用 调用backgroundFlushCommits(bool synchronous) 发送到服务器端.
@Override
public void mutate(Mutation m) throws InterruptedIOException,
RetriesExhaustedWithDetailsException {
mutate(Arrays.asList(m));
}
@Override
public void mutate(List ms) throws InterruptedIOException,
RetriesExhaustedWithDetailsException {
if (closed) {
throw new IllegalStateException("Cannot put when the BufferedMutator is closed.");
}
long toAddSize = 0;
for (Mutation m : ms) {
if (m instanceof Put) {
validatePut((Put) m);
}
toAddSize += m.heapSize();
}
// This behavior is highly non-intuitive... it does not protect us against
// 94-incompatible behavior, which is a timing issue because hasError, the below code
// and setter of hasError are not synchronized. Perhaps it should be removed.
if (ap.hasError()) {
currentWriteBufferSize.addAndGet(toAddSize);
writeAsyncBuffer.addAll(ms);
backgroundFlushCommits(true);
} else {
currentWriteBufferSize.addAndGet(toAddSize);
writeAsyncBuffer.addAll(ms);
}
// Now try and queue what needs to be queued.
while (currentWriteBufferSize.get() > writeBufferSize) {
backgroundFlushCommits(false);
}
}4. 做一些预处理，然后调用 protected AsyncProcess ap; 的 submit 方法
private void backgroundFlushCommits(boolean synchronous) throws
InterruptedIOException,
RetriesExhaustedWithDetailsException {
LinkedList buffer = new LinkedList<>();
// Keep track of the size so that this thread doesn't spin forever
long dequeuedSize = 0;
try {
// Grab all of the available mutations.
Mutation m;
// If there's no buffer size drain everything. If there is a buffersize drain up to twice
// that amount. This should keep the loop from continually spinning if there are threads
// that keep adding more data to the buffer.
while (
(writeBufferSize <= 0 || dequeuedSize < (writeBufferSize * 2) || synchronous)
&& (m = writeAsyncBuffer.poll()) != null) {
// buffer 是即将提交到服务器端的put数据
buffer.add(m);
long size = m.heapSize();
dequeuedSize += size;
currentWriteBufferSize.addAndGet(-size);
}
if (!synchronous && dequeuedSize == 0) {
return;
}
if (!synchronous) {
ap.submit(tableName, buffer, true, null, false);
if (ap.hasError()) {
LOG.debug(tableName + ": One or more of the operations have failed -"
+ " waiting for all operation in progress to finish (successfully or not)");
}
}
if (synchronous || ap.hasError()) {
while (!buffer.isEmpty()) {
//调用 protected AsyncProcess ap; 的sbumit 方法
ap.submit(tableName, buffer, true, null, false);
}
RetriesExhaustedWithDetailsException error =
ap.waitForAllPreviousOpsAndReset(null, tableName.getNameAsString());
if (error != null) {
if (listener == null) {
throw error;
} else {
this.listener.onException(error, this);
}
}
}
} finally {
for (Mutation mut : buffer) {
long size = mut.heapSize();
currentWriteBufferSize.addAndGet(size);
dequeuedSize -= size;
writeAsyncBuffer.add(mut);
}
}
}
5. 将put 按照regionserver分类，然后 调用 submitMultiActions 进行提交.
public AsyncRequestFuture submit(ExecutorService pool, TableName tableName,
List rows, boolean atLeastOne, Batch.Callback callback,
boolean needResults) throws InterruptedIOException {
if (rows.isEmpty()) {
return NO_REQS_RESULT;
}
Map> actionsByServer =
new HashMap>();
List> retainedActions = new ArrayList>(rows.size());
NonceGenerator ng = this.connection.getNonceGenerator();
long nonceGroup = ng.getNonceGroup(); // Currently, nonce group is per entire client.
// Location errors that happen before we decide what requests to take.
List locationErrors = null;
List locationErrorRows = null;
do {
// Wait until there is at least one slot for a new task.
waitForMaximumCurrentTasks(maxTotalConcurrentTasks - 1, tableName.getNameAsString());
// Remember the previous decisions about regions or region servers we put in the
// final multi.
Map regionIncluded = new HashMap();
Map serverIncluded = new HashMap();
int posInList = -1;
Iterator it = rows.iterator();
while (it.hasNext()) {
Row r = it.next();
HRegionLocation loc;
try {
if (r == null) {
throw new IllegalArgumentException("#" + id + ", row cannot be null");
}
// Make sure we get 0-s replica.
RegionLocations locs = connection.locateRegion(
tableName, r.getRow(), true, true, RegionReplicaUtil.DEFAULT_REPLICA_ID);
if (locs == null || locs.isEmpty() || locs.getDefaultRegionLocation() == null) {
throw new IOException("#" + id + ", no location found, aborting submit for"
+ " tableName=" + tableName + " rowkey=" + Bytes.toStringBinary(r.getRow()));
}
loc = locs.getDefaultRegionLocation();
} catch (IOException ex) {
locationErrors = new ArrayList();
locationErrorRows = new ArrayList();
LOG.error("Failed to get region location ", ex);
// This action failed before creating ars. Retain it, but do not add to submit list.
// We will then add it to ars in an already-failed state.
retainedActions.add(new Action(r, ++posInList));
locationErrors.add(ex);
locationErrorRows.add(posInList);
it.remove();
break; // Backward compat: we stop considering actions on location error.
}
if (canTakeOperation(loc, regionIncluded, serverIncluded)) {
Action action = new Action(r, ++posInList);
setNonce(ng, r, action);
retainedActions.add(action);
// TODO: replica-get is not supported on this path
byte[] regionName = loc.getRegionInfo().getRegionName();
// 在这个方法中 根据server，将put分类，这样发送到同一个server的put会被一起处理
addAction(loc.getServerName(), regionName, action, actionsByServer, nonceGroup);
it.remove();
}
}
} while (retainedActions.isEmpty() && atLeastOne && (locationErrors == null));
if (retainedActions.isEmpty()) return NO_REQS_RESULT;
return submitMultiActions(tableName, retainedActions, nonceGroup, callback, null, needResults,
locationErrors, locationErrorRows, actionsByServer, pool);
}
6. submitMultiActions => sendMultiAction, 针对每一个 server 调用 getNewMultiActionRunnable（）生成一个处理的线程.即SingleServerRequestRunnable.,可以看到最后实际用的是
callable = createCallable(server, tableName, multiAction);，继续跟下去会发现是调用的 MultiServerCallable 中的 call 函数中的 responseProto = getStub().multi(controller, requestProto); 将put 提交到 server 中.
private final class SingleServerRequestRunnable implements Runnable {
private final MultiAction multiAction;
private final int numAttempt;
private final ServerName server;
private final Set> callsInProgress;
private SingleServerRequestRunnable(
MultiAction multiAction, int numAttempt, ServerName server,
Set> callsInProgress) {
this.multiAction = multiAction;
this.numAttempt = numAttempt;
this.server = server;
this.callsInProgress = callsInProgress;
}
@Override
public void run() {
MultiResponse res;
MultiServerCallable callable = null;
try {
callable = createCallable(server, tableName, multiAction);
try {
RpcRetryingCaller caller = createCaller(callable);
if (callsInProgress != null) callsInProgress.add(callable);
res = caller.callWithoutRetries(callable, timeout);
if (res == null) {
// Cancelled
return;
}
