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https://issues.apache.org/jira/browse/HBASE-16345?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15475327#comment-15475327
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huaxiang sun commented on HBASE-16345:
--------------------------------------
A side note, we found that the current scan does not honor the following
{code}
scan.setConsistency(Consistency.TIMELINE);
scan.setReplicaId(1);
{code}
The scan actually scans all replicas. This is not consistent with the Get. If
this is an issue, I can create a new jira to address it.
The following testing case shows the issue:
{code}
@Test public void testReplicaScanWithReplica() throws IOException {
// Create table then get the single region for our new table.
HTableDescriptor hdt = HTU.createTableDescriptor("testReplicaScanTable");
hdt.setRegionReplication(NB_SERVERS);
try {
Table table = HTU.createTable(hdt, new byte[][] { f }, null);
Put p = new Put(row);
p.addColumn(f, row, row);
table.put(p);
// Flush so it can be picked by the replica refresher thread
HTU.flush(table.getName());
// Sleep for some time until data is picked up by replicas
try {
Thread.sleep(2 * REFRESH_PERIOD);
} catch (InterruptedException e1) {
LOG.error(e1);
}
// But if we ask for stale we will get it
// Instantiating the Scan class
Scan scan = new Scan();
// Scanning the required columns
scan.addFamily(f);
scan.setConsistency(Consistency.TIMELINE);
scan.setReplicaId(1);
// Getting the scan result
ResultScanner scanner = table.getScanner(scan);
Result r = scanner.next();
Assert.assertTrue(r.isStale());
} finally {
HTU.getHBaseAdmin().disableTable(hdt.getTableName());
HTU.deleteTable(hdt.getTableName());
}
}
{code}
> RpcRetryingCallerWithReadReplicas#call() should catch some RegionServer
> Exceptions
> ----------------------------------------------------------------------------------
>
> Key: HBASE-16345
> URL: https://issues.apache.org/jira/browse/HBASE-16345
> Project: HBase
> Issue Type: Bug
> Components: Client
> Affects Versions: 2.0.0
> Reporter: huaxiang sun
> Assignee: huaxiang sun
> Attachments: HBASE-16345-v001.patch, HBASE-16345.master.001.patch,
> HBASE-16345.master.002.patch, HBASE-16345.master.003.patch,
> HBASE-16345.master.004.patch, HBASE-16345.master.005.patch
>
>
> Update for the description. Debugged more at this front based on the comments
> from Enis.
> The cause is that for the primary replica, if its retry is exhausted too
> fast, f.get() [1] returns ExecutionException. This Exception needs to be
> ignored and continue with the replicas.
> The other issue is that after adding calls for the replicas, if the first
> completed task gets ExecutionException (due to the retry exhausted), it
> throws the exception to the client[2].
> In this case, it needs to loop through these tasks, waiting for the success
> one. If no one succeeds, throw exception.
> Similar for the scan as well
> [1]
> https://github.com/apache/hbase/blob/master/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RpcRetryingCallerWithReadReplicas.java#L197
> [2]
> https://github.com/apache/hbase/blob/master/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RpcRetryingCallerWithReadReplicas.java#L219
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