[
https://issues.apache.org/jira/browse/HBASE-16132?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
binlijin updated HBASE-16132:
-----------------------------
Description:
We have find some corner case, when regionserver is busy and last a long time.
Some scanner may return null even if they do not scan all data.
We find in ScannerCallableWithReplicas there is a case do not handler correct,
when cs.poll timeout and do not return any result , it is will return a null
result, so scan get null result, and end the scan.
```
try {
Future<Pair<Result[], ScannerCallable>> f = cs.poll(timeout,
TimeUnit.MILLISECONDS);
if (f != null) {
Pair<Result[], ScannerCallable> r = f.get(timeout,
TimeUnit.MILLISECONDS);
if (r != null && r.getSecond() != null) {
updateCurrentlyServingReplica(r.getSecond(), r.getFirst(), done,
pool);
}
return r == null ? null : r.getFirst(); // great we got an answer
}
} catch (ExecutionException e) {
RpcRetryingCallerWithReadReplicas.throwEnrichedException(e, retries);
} catch (CancellationException e) {
throw new InterruptedIOException(e.getMessage());
} catch (InterruptedException e) {
throw new InterruptedIOException(e.getMessage());
} catch (TimeoutException e) {
throw new InterruptedIOException(e.getMessage());
} finally {
// We get there because we were interrupted or because one or more of the
// calls succeeded or failed. In all case, we stop all our tasks.
cs.cancelAll();
}
return null; // unreachable
```
> Scan do not return all result when regionserver is busy.
> --------------------------------------------------------
>
> Key: HBASE-16132
> URL: https://issues.apache.org/jira/browse/HBASE-16132
> Project: HBase
> Issue Type: Bug
> Reporter: binlijin
> Attachments: HBASE-16132.patch
>
>
> We have find some corner case, when regionserver is busy and last a long
> time. Some scanner may return null even if they do not scan all data.
> We find in ScannerCallableWithReplicas there is a case do not handler
> correct, when cs.poll timeout and do not return any result , it is will
> return a null result, so scan get null result, and end the scan.
> ```
> try {
> Future<Pair<Result[], ScannerCallable>> f = cs.poll(timeout,
> TimeUnit.MILLISECONDS);
> if (f != null) {
> Pair<Result[], ScannerCallable> r = f.get(timeout,
> TimeUnit.MILLISECONDS);
> if (r != null && r.getSecond() != null) {
> updateCurrentlyServingReplica(r.getSecond(), r.getFirst(), done,
> pool);
> }
> return r == null ? null : r.getFirst(); // great we got an answer
> }
> } catch (ExecutionException e) {
> RpcRetryingCallerWithReadReplicas.throwEnrichedException(e, retries);
> } catch (CancellationException e) {
> throw new InterruptedIOException(e.getMessage());
> } catch (InterruptedException e) {
> throw new InterruptedIOException(e.getMessage());
> } catch (TimeoutException e) {
> throw new InterruptedIOException(e.getMessage());
> } finally {
> // We get there because we were interrupted or because one or more of
> the
> // calls succeeded or failed. In all case, we stop all our tasks.
> cs.cancelAll();
> }
> return null; // unreachable
> ```
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