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jirapos...@reviews.apache.org commented on HBASE-4014:
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Nice work, Eugene.  I think we're getting close.  Just two suggested 
improvements below.

The main question still open to debate, I think, is whether or not aborting the 
server on unhandled exceptions is appropriate.

On the one hand, aborting takes the fail-fast approach and makes buggy 
coprocessors much more visible.  It's a lot more likely that a bug will be 
noticed and fixed if it brings down a region server!

On the other hand, I think coprocessors already pose enough of a stability risk 
to a cluster.  I think we should be working to minimize that by containing the 
impact that a buggy coprocessor can have.  If they coprocessor really wants or 
needs to trigger an abort, it can already do so, since 
(Master|RegionServer)Services extend Server, which extends Abortable.

I think I'd be more in favor of removing the coprocessor from the active set 
(we should make this as visible as possible so it's clear the coprocessor is no 
longer "active"), or at least wrapping the exception in a DoNotRetryIOException 
and communicating it back to the client?  Maybe both?

I guess I'd be okay with a configuration option to abort on error (I think a 
single config option is sufficient), as long as it's disabled by default.  But 
that would still imply we need some other handling when the option is disabled.


src/main/java/org/apache/hadoop/hbase/coprocessor/CoprocessorHost.java
<https://reviews.apache.org/r/969/#comment3299>

    I would just synchronize the set here:
    
    Set<String> coprocessorNames = Collections.synchronizedSet(new 
HashSet<String>());



src/main/java/org/apache/hadoop/hbase/coprocessor/CoprocessorHost.java
<https://reviews.apache.org/r/969/#comment3300>

    If you move this into loadInstance() then you don't have to duplicate it 
elsewhere, since all the other load methods wind up calling that.


- Gary


On 2011-08-10 22:48:08, Eugene Koontz wrote:
bq.  
bq.  -----------------------------------------------------------
bq.  This is an automatically generated e-mail. To reply, visit:
bq.  https://reviews.apache.org/r/969/
bq.  -----------------------------------------------------------
bq.  
bq.  (Updated 2011-08-10 22:48:08)
bq.  
bq.  
bq.  Review request for hbase, Gary Helmling and Mingjie Lai.
bq.  
bq.  
bq.  Summary
bq.  -------
bq.  
bq.  https://issues.apache.org/jira/browse/HBASE-4014 Coprocessors: Flag the 
presence of coprocessors in logged exceptions
bq.  
bq.  The general gist here is to wrap each of 
{Master,RegionServer}CoprocessorHost's coprocessor call inside a 
bq.  
bq.  "try { ... } catch (Throwable e) { handleCoprocessorThrowable(e) }"
bq.  
bq.  block. 
bq.  
bq.  handleCoprocessorThrowable() is responsible for either passing 'e' along 
to the client (if 'e' is an IOException) or, otherwise, aborting the service 
(Regionserver or Master).
bq.  
bq.  The abort message contains a list of the loaded coprocessors for crash 
analysis.
bq.  
bq.  
bq.  This addresses bug HBASE-4014.
bq.      https://issues.apache.org/jira/browse/HBASE-4014
bq.  
bq.  
bq.  Diffs
bq.  -----
bq.  
bq.    src/main/java/org/apache/hadoop/hbase/coprocessor/CoprocessorHost.java 
18ba6e7 
bq.    src/main/java/org/apache/hadoop/hbase/master/HMaster.java 8beeb68 
bq.    src/main/java/org/apache/hadoop/hbase/master/MasterCoprocessorHost.java 
aa930f5 
bq.    src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java 
23225d7 
bq.    
src/main/java/org/apache/hadoop/hbase/regionserver/RegionCoprocessorHost.java 
c44da73 
bq.    
src/test/java/org/apache/hadoop/hbase/coprocessor/TestMasterCoprocessorException.java
 PRE-CREATION 
bq.    
src/test/java/org/apache/hadoop/hbase/coprocessor/TestRegionServerCoprocessorException.java
 PRE-CREATION 
bq.  
bq.  Diff: https://reviews.apache.org/r/969/diff
bq.  
bq.  
bq.  Testing
bq.  -------
bq.  
bq.  patch includes two tests:
bq.  
bq.  TestMasterCoprocessorException.java
bq.  TestRegionServerCoprocessorException.java
bq.  
bq.  both tests pass in my build environment.
bq.  
bq.  
bq.  Thanks,
bq.  
bq.  Eugene
bq.  
bq.



> Coprocessors: Flag the presence of coprocessors in logged exceptions
> --------------------------------------------------------------------
>
>                 Key: HBASE-4014
>                 URL: https://issues.apache.org/jira/browse/HBASE-4014
>             Project: HBase
>          Issue Type: Improvement
>          Components: coprocessors
>            Reporter: Andrew Purtell
>            Assignee: Eugene Koontz
>             Fix For: 0.92.0
>
>         Attachments: HBASE-4014.patch, HBASE-4014.patch, HBASE-4014.patch, 
> HBASE-4014.patch, HBASE-4014.patch
>
>
> For some initial triage of bug reports for core versus for deployments with 
> loaded coprocessors, we need something like the Linux kernel's taint flag, 
> and list of linked in modules that show up in the output of every OOPS, to 
> appear above or below exceptions that appear in the logs.

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