[infinispan-dev] Need to understand, ClusteredCacheWithElasticsearchIndexManagerIT

Gustavo Fernandes gustavo at infinispan.org
Wed May 10 09:33:38 EDT 2017


The test fails every time NodeB (cache2) happens to *not be* the primary
owner of 'newGoat', and needs to forward the command to NodeA. Sequence of
events:

1) [NodeB] Compute is called, key is 'newGoat'
2) [NodeB] Command gets visited by the QueryInterceptor, that suspends the
execution
3) [NodeB] Owner for 'newGoat' is nodeA, so nodeB forwards the command to
nodeA

4) [NodeA] Command gets visited by the QueryInterceptor, that suspends the
execution
5) [NodeA] perform() is called in the Compute command
6) [NodeA] Command is then sent to NodeB, which is a backup owner

7) [NodeB] Command gets visited by the QueryInterceptor, that suspends the
execution
8) [NodeB] perform() is called in the compute command
9) [NodeB] QueryInterceptor resumes execution. Since command was originated
remotely, no indexing is done (due to Index.LOCAL)

9) [NodeA] Receive response from the call done on 6)
10)[NodeA] resumes execution from the QueryInterceptor from 4)
11)[NodeA] Since command was originated remotely, no indexing is done (due
to Index.LOCAL)

12)[NodeB] receives response from 3). At this point *the computed value is
available* as the return type of the remote invocation
13)[NodeB] resumes the QueryInterceptor invocation from 2)
14)[NodeB] processComputes is then executed, but since the computedValue is
not available in the command itself nor in the context, indexing is skipped
since there is no value to index or remove


Looking at the method visitComputCommand, the variable "rv" stores the
return value from the command, but it's not being used, instead the
stateBeforeCompute is used which is always null in this scenario,
because it is evaluated on 2) which is before the the key exists in the
data container:

return invokeNextThenAccept(ctx, command, (rCtx, rCommand, rv) ->
processComputeCommand(((ComputeCommand) rCommand), rCtx,
stateBeforeCompute, null));


Gustavo


On Tue, May 9, 2017 at 2:21 PM, Katia Aresti <karesti at redhat.com> wrote:

> Hi all,
>
> I'm really struggling with something in order to finish the compute
> methods.
>
> I added a test in *ClusteredCacheWithElasticsearchIndexManagerIT*
>
> public void testToto() throws Exception {
>     SearchManager searchManager = Search.getSearchManager(cache2);
>     QueryBuilder queryBuilder = searchManager
>           .buildQueryBuilderForClass(Person.class)
>           .get();
>     Query allQuery = queryBuilder.all().createQuery();
>
>     String key = "newGoat";
>     Person person4 = new Person(key, "eats something", 42);
>
>     cache2.putIfAbsent(key, person4);
>     StaticTestingErrorHandler.assertAllGood(cache1, cache2);
>
>     List<Person> found = searchManager.<Person>getQuery(allQuery, Person.class).list();
>     assertEquals(1, found.size());
>     assertTrue(found.contains(person4));
> }
>
> I put some logs in the processPutKeyValueCommand method in the
> *QueryInterceptor* to explain what is happening.
>
> *2 threads*
> Sometimes two threads get involved.
>
> = Thread 72 First (or second) call
> It happens from a non local Node. The so the shouldModifyIndexes says
> "no, you should not modify any index" because the
> IndexModificationStrategy is set to "LOCAL ONLY". [1]
>
> 72 ctx.getOrigin() = ClusteredCacheWithElasticsearc
> hIndexManagerIT-NodeB-19565
> 72 should modify false
> 72 previousValue null
> 72 putValue Person{name='newGoat', blurb='eats something', age=42,
> dateOfGraduation=null} // value in the command
> 72 contextValue Person{name='newGoat', blurb='eats something', age=42,
> dateOfGraduation=null} //value in the invocation context
>
> = Thread 48 Second (or first) call
> the origin is null, and this is considered as a LOCAL in the
> SingleKeyNonTxInvocationContext. [2] In this case, the index is modified
> correctly, the value in the context has already been set up by the
> PutKeyValueCommand and the index get's correctly updated.
>
> 48 ctx.getOrigin() = null
> 48 should modify true
> 48 previousValue null
> 48 putValue Person{name='newGoat', blurb='eats something', age=42,
> dateOfGraduation=null}
> 48 contextValue Person{name='newGoat', blurb='eats something', age=42,
> dateOfGraduation=null}
>
> And everything is ok. Everything is fine too in the case of a compute
> method instead of the put method.
>
> But sometimes, this is not executed like that.
>
> *3 threads*
>
> What is a bit more weird to me is this second scenario where the commands
> are executed both from non local nodes (A and B). And so the index is not
> updated.
> But  just later, another thread get's involved and calls the
> QueryInterceptor with a invocation context where the command has not been
> executed (the value is not inside the context and the debugger does not
> enter in the perform method, this has happened just twice before). This
> call is coming like from a callback? in the QueueAsyncInvocationStage.
>
> 80 ctx.getOrigin() = ClusteredCacheWithElasticsearc
> hIndexManagerIT-NodeA-65110
> 80 should modify false
> 80 prev null
> 80 putValue Person{name='newGoat', blurb='eats something', age=42,
> dateOfGraduation=null}
> 80 contextValue Person{name='newGoat', blurb='eats something', age=42,
> dateOfGraduation=null}
>
> 38 ctx.getOrigin() = ClusteredCacheWithElasticsearc
> hIndexManagerIT-NodeB-35919
> 38 should modify false
> 38 prev null
> 38 putValue Person{name='newGoat', blurb='eats something', age=42,
> dateOfGraduation=null}
> 38 contextValue Person{name='newGoat', blurb='eats something', age=42,
> dateOfGraduation=null}
>
> 48 ctx.getOrigin() = null
> 48 should modify true
> 48 prev null
> 48 putValue Person{name='newGoat', blurb='eats something', age=42,
> dateOfGraduation=null}
> 48 contextValue null
>
>
> This execution works perfectly with PutKeyValueCommand. But don't work wth
> compute.
>
> The "computed value" is not inside the Command like put, replace or
> others. It is computed in the perform method (if needed). So, the first
> time the command is executed in A, the computed value is in the context,
> but the index is not updated. Second call, executed in B, value in context,
> but the index is not updated. The magic callback is executed, but the
> computed value is nowhere because the command is not executed a third time,
> so the context is null.
>
> Can somebody please give me some light on this and explain to me what am I
> missing ? Other tests are failing for the same problem,
> like org.infinispan.query.blackbox.ClusteredCacheWithInfinis
> panDirectoryTest
>
> Thank you very much for your help !
>
> Katia
>
> [1] https://github.com/infinispan/infinispan/blob/master/
> query/src/main/java/org/infinispan/query/backend/Index
> ModificationStrategy.java#L50
> [2] https://github.com/infinispan/infinispan/blob/master/
> core/src/main/java/org/infinispan/context/SingleKeyNonTxInvo
> cationContext.java#L39
>
>
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>
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