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From "Ankit Singhal (JIRA)" <j...@apache.org>
Subject [jira] [Comment Edited] (PHOENIX-3964) Index.preWALRestore should handle index write failure
Date Fri, 23 Jun 2017 13:06:02 GMT

    [ https://issues.apache.org/jira/browse/PHOENIX-3964?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16060859#comment-16060859
] 

Ankit Singhal edited comment on PHOENIX-3964 at 6/23/17 1:06 PM:
-----------------------------------------------------------------

bq. PHOENIX-3072 only handle the index regions which are on the same RegionServer, but the
index regions may also on other RegionServers.
IMO, index regions will come up on all regionserver before data region during the race.

bq. in Indexer.postOpen, the IOException will be caught, so the data region can open successfully
even if the index write is failed again
No, it will kill the region server because of KillServerOnFailurePolicy. And, We will lose
the cached edits and not sure we will get a chance to replay them again.
{code}this.abortable.abort(msg, cause);{code}

I'm now becoming sceptical about this change, cached WAL replay after postOpen could overwrite
the new writes, if there are new overlapped writes coming to the data table(which eventually
also written to index table) because now the region is open and available.(May result in data
loss)







was (Author: ankit@apache.org):
bq. PHOENIX-3072 only handle the index regions which are on the same RegionServer, but the
index regions may also on other RegionServers.
IMO, index regions will come up on all regionserver before data region during the race.

bq. in Indexer.postOpen, the IOException will be caught, so the data region can open successfully
even if the index write is failed again
No, it will kill the region server because of KillServerOnFailurePolicy. And, We will lose
the cached edits and not sure we will get a chance to replay them again.
{code}this.abortable.abort(msg, cause);{code}

I'm now becoming sceptical about this change, cached WAL replay after postOpen could overwrite
the new writes, if there are new overlapped writes coming to the data table(which eventually
also written to index table) during the replay because now the region is open and available.(May
result in data loss)






> Index.preWALRestore should handle index write failure
> -----------------------------------------------------
>
>                 Key: PHOENIX-3964
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-3964
>             Project: Phoenix
>          Issue Type: Bug
>    Affects Versions: 4.10.0
>            Reporter: chenglei
>         Attachments: PHOENIX-3964_v1.patch
>
>
> When I restarted my hbase cluster a certain time, I noticed some regions are in FAILED_OPEN
state and the RegionServers have some error logs as following:
> {code:java}
> 2017-06-20 12:31:30,493 ERROR [RS_OPEN_REGION-rsync:60020-3] handler.OpenRegionHandler:
Failed open of region=BIZARCH_NS_PRODUCT.BIZTRACER_SPAN,0100134e-7ddf-4d13-ab77-6f0d683e5fad_0,1487594358223.57a7be72f9beaeb4285529ac6236f4e5.,
starting to roll back the global memstore size.
> org.apache.phoenix.hbase.index.exception.MultiIndexWriteFailureException: Failed to write
to multiple index tables
>         at org.apache.phoenix.hbase.index.write.recovery.TrackingParallelWriterIndexCommitter.write(TrackingParallelWriterIndexCommitter.java:221)
>         at org.apache.phoenix.hbase.index.write.IndexWriter.write(IndexWriter.java:185)
>         at org.apache.phoenix.hbase.index.write.RecoveryIndexWriter.write(RecoveryIndexWriter.java:75)
>         at org.apache.phoenix.hbase.index.Indexer.preWALRestore(Indexer.java:554)
>         at org.apache.hadoop.hbase.regionserver.RegionCoprocessorHost$58.call(RegionCoprocessorHost.java:1312)
>         at org.apache.hadoop.hbase.regionserver.RegionCoprocessorHost$RegionOperation.call(RegionCoprocessorHost.java:1517)
>         at org.apache.hadoop.hbase.regionserver.RegionCoprocessorHost.execOperation(RegionCoprocessorHost.java:1592)
>         at org.apache.hadoop.hbase.regionserver.RegionCoprocessorHost.execOperation(RegionCoprocessorHost.java:1549)
>         at org.apache.hadoop.hbase.regionserver.RegionCoprocessorHost.preWALRestore(RegionCoprocessorHost.java:1308)
>         at org.apache.hadoop.hbase.regionserver.HRegion.replayRecoveredEdits(HRegion.java:3338)
>         at org.apache.hadoop.hbase.regionserver.HRegion.replayRecoveredEditsIfAny(HRegion.java:3220)
>         at org.apache.hadoop.hbase.regionserver.HRegion.initializeRegionStores(HRegion.java:823)
>         at org.apache.hadoop.hbase.regionserver.HRegion.initializeRegionInternals(HRegion.java:716)
>         at org.apache.hadoop.hbase.regionserver.HRegion.initialize(HRegion.java:687)
>         at org.apache.hadoop.hbase.regionserver.HRegion.openHRegion(HRegion.java:4596)
>         at org.apache.hadoop.hbase.regionserver.HRegion.openHRegion(HRegion.java:4566)
>         at org.apache.hadoop.hbase.regionserver.HRegion.openHRegion(HRegion.java:4538)
>         at org.apache.hadoop.hbase.regionserver.HRegion.openHRegion(HRegion.java:4494)
>         at org.apache.hadoop.hbase.regionserver.HRegion.openHRegion(HRegion.java:4445)
>         at org.apache.hadoop.hbase.regionserver.handler.OpenRegionHandler.openRegion(OpenRegionHandler.java:465)
>         at org.apache.hadoop.hbase.regionserver.handler.OpenRegionHandler.process(OpenRegionHandler.java:139)
>         at org.apache.hadoop.hbase.executor.EventHandler.run(EventHandler.java:128)
>         at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
>         at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
>         at java.lang.Thread.run(Thread.java:745)
> {code}
> When I look the code of Index.preWALRestore method, I find RecoveryIndexWriter.write
method is used to write the indexUpdates in following line 543: 
>    
> {code:java}
>  
> 526  public void preWALRestore(ObserverContext<RegionCoprocessorEnvironment> env,
HRegionInfo info,
> 527      HLogKey logKey, WALEdit logEdit) throws IOException {
> 528      if (this.disabled) {
> 529          super.preWALRestore(env, info, logKey, logEdit);
> 530          return;
> 531        }
> 532    // TODO check the regions in transition. If the server on which the region lives
is this one,
> 533    // then we should rety that write later in postOpen.
> 534    // we might be able to get even smarter here and pre-split the edits that are
server-local
> 535    // into their own recovered.edits file. This then lets us do a straightforward
recovery of each
> 536    // region (and more efficiently as we aren't writing quite as hectically from
this one place).
> 537
> 538    /*
> 539     * Basically, we let the index regions recover for a little while long before
retrying in the
> 540     * hopes they come up before the primary table finishes.
> 541     */
> 542    Collection<Pair<Mutation, byte[]>> indexUpdates = extractIndexUpdate(logEdit);
> 543    recoveryWriter.write(indexUpdates, true);
> 544  }
> {code}
> but the RecoveryIndexWriter.write method is as following, it directly throws Exception
except non-existing tables, so RecoveryIndexWriter's failurePolicy(which is StoreFailuresInCachePolicy
by default) even has no opportunity to be used,  and it leads to Index.failedIndexEdits which
is filled by the StoreFailuresInCachePolicy is always empty.
> {code:java}
>  public void write(Collection<Pair<Mutation, byte[]>> toWrite, boolean allowLocalUpdates)
throws IOException {
>         try {
>             write(resolveTableReferences(toWrite), allowLocalUpdates);
>         } catch (MultiIndexWriteFailureException e) {
>             for (HTableInterfaceReference table : e.getFailedTables()) {
>                 if (!admin.tableExists(table.getTableName())) {
>                     LOG.warn("Failure due to non existing table: " + table.getTableName());
>                     nonExistingTablesList.add(table);
>                 } else {
>                     throw e;
>                 }
>             }
>         }
>     }
> {code}
> So the Index.postOpen method seems useless, because the updates Multimap in following
500 line which is got from Index.failedIndexEdits is always empty.
> {code:java}
> 499  public void postOpen(final ObserverContext<RegionCoprocessorEnvironment> c)
{
> 500     Multimap<HTableInterfaceReference, Mutation> updates = failedIndexEdits.getEdits(c.getEnvironment().getRegion());
> 501     
> 502     if (this.disabled) {
> 503         super.postOpen(c);
> 504         return;
> 505      }
> 506   
> 507     //if we have no pending edits to complete, then we are done
> 508     if (updates == null || updates.size() == 0) {
> 509       return;
> 510      }
> 511
> 512     LOG.info("Found some outstanding index updates that didn't succeed during"
> 513            + " WAL replay - attempting to replay now.");
> 514    
> 515     // do the usual writer stuff, killing the server again, if we can't manage to
make the index
> 516     // writes succeed again
> 517     try {
> 518        writer.writeAndKillYourselfOnFailure(updates, true);
> 519     } catch (IOException e) {
> 520              LOG.error("During WAL replay of outstanding index updates, "
> 521                    + "Exception is thrown instead of killing server during index
writing", e);
> 522    }
> 523  }
> {code}
> So  I think in Index.preWALRestore method,  we should use RecoveryWriter.writeAndKillYourselfOnFailure
method to write the indexUpdates and handle index write failure, not just use the RecoveryIndexWriter.write
method.
>  



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