chenxu14 commented on a change in pull request #656: HBASE-23063 Add an option
to enable multiget in parallel
URL: https://github.com/apache/hbase/pull/656#discussion_r328452649
##########
File path:
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RSRpcServices.java
##########
@@ -934,13 +939,61 @@ private Result increment(final HRegion region, final
OperationQuota quota,
builder.addResultOrException(resultOrExceptionBuilder.build());
}
}
+ // do multiget in parallel
+ if (getCtxs != null && !getCtxs.isEmpty()) {
+ doParallelGet(getCtxs, cellsToReturn, builder);
+ }
// Finish up any outstanding mutations
if (!CollectionUtils.isEmpty(mutations)) {
doNonAtomicBatchOp(builder, region, quota, mutations, cellScanner,
spaceQuotaEnforcement);
}
return cellsToReturn;
}
+ private void doParallelGet(List<GetContext> getCtxs, List<CellScannable>
cellsToReturn,
+ RegionActionResult.Builder builder) throws ServiceException {
+ ResultOrException.Builder resultOrExceptionBuilder = null;
+ CountDownLatch latch = new CountDownLatch(getCtxs.size());
+ List<GetActionHandler> handlers = new ArrayList<>(getCtxs.size());
+ for (GetContext getCtx : getCtxs) {
+ GetActionHandler handler = new GetActionHandler(getCtx, latch);
+ this.regionServer.executorService.submit(handler);
+ handlers.add(handler);
+ }
+ try {
+ latch.await();
Review comment:
The fallowing Test has no problem @ramatronics
The main thread will not hang
```
public class Test {
public static void main(String[] args) throws Throwable {
CountDownLatch doneSignal = new CountDownLatch(2);
new Thread(new WorkerRunnable(doneSignal)).start();
new Thread(new WorkerRunnable(doneSignal)).start();
Thread.sleep(5000);
doneSignal.await();
System.out.println("await happend");
}
}
class WorkerRunnable implements Runnable {
private final CountDownLatch doneSignal;
WorkerRunnable(CountDownLatch doneSignal) {
this.doneSignal = doneSignal;
}
public void run() {
System.out.println("countDown happend");
doneSignal.countDown();
}
}
```
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