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https://issues.apache.org/jira/browse/HBASE-4014?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13098279#comment-13098279
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jirapos...@reviews.apache.org commented on HBASE-4014:
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bq.  On 2011-08-12 23:46:30, Gary Helmling wrote:
bq.  > Nice work, Eugene.  I think we're getting close.  Just two suggested 
improvements below.
bq.  > 
bq.  > The main question still open to debate, I think, is whether or not 
aborting the server on unhandled exceptions is appropriate.
bq.  > 
bq.  > 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!
bq.  > 
bq.  > 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.
bq.  > 
bq.  > 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?
bq.  > 
bq.  > 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.
bq.  
bq.  Michael Stack wrote:
bq.      I like Gary's reasoning here.

Thanks Gary and Michael for your comments. Latest patch defines a new config 
option hbase.coprocessor.abort_on_error, which defaults to false. 

CoprocessorHost#handleCoprocessorThrowable() removes the buggy coprocessor from 
its active set of coprocesors.

As Gary said, a coprocessor author can explicitly code their coprocessor to 
abort if they want to. On the other hand, coprocessor authors might like to 
develop or test without having to explicitly take care of this, so perhaps 
hbase.coprocessor.abort_on_error=true would be useful for them to define.


bq.  On 2011-08-12 23:46:30, Gary Helmling wrote:
bq.  > src/main/java/org/apache/hadoop/hbase/coprocessor/CoprocessorHost.java, 
line 71
bq.  > <https://reviews.apache.org/r/969/diff/6/?file=31373#file31373line71>
bq.  >
bq.  >     I would just synchronize the set here:
bq.  >     
bq.  >     Set<String> coprocessorNames = Collections.synchronizedSet(new 
HashSet<String>());

Fixed, thanks.


bq.  On 2011-08-12 23:46:30, Gary Helmling wrote:
bq.  > src/main/java/org/apache/hadoop/hbase/coprocessor/CoprocessorHost.java, 
line 106
bq.  > <https://reviews.apache.org/r/969/diff/6/?file=31373#file31373line106>
bq.  >
bq.  >     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.

moved to loadInstance(), thanks.


- Eugene


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On 2011-09-06 19:08:59, 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 2011-09-06 19:08:59)
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 
4e492e1 
bq.    src/main/java/org/apache/hadoop/hbase/master/HMaster.java 3f60653 
bq.    src/main/java/org/apache/hadoop/hbase/master/MasterCoprocessorHost.java 
aa930f5 
bq.    src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java 
8ff6e62 
bq.    
src/main/java/org/apache/hadoop/hbase/regionserver/RegionCoprocessorHost.java 
5796413 
bq.    src/main/resources/hbase-default.xml 2c8f44b 
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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