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From Till Rohrmann <trohrm...@apache.org>
Subject Re: ALS implementation
Date Mon, 08 Jun 2015 11:59:15 GMT
Hi Felix, I tried to reproduce the problem with the *Hash join exceeded
maximum number of recursions, without reducing partitions enough to be
memory resident.* exception. I used the same data set and the same settings
for ALS. However, on my machine it runs through without this exception.
Could you tell me on what computer you’re running the program? How many
cores, how much memory do you give the JVM as standard value?

How does your program looks like? Do you only calculate the factorization
and print it? Or do you also try to calculate predictions?

I found only one possible join operation where this exception could be
thrown, namely the predict operation. However, the join key should be
unique for the build side at this position, because you join the the user
vectors with the user ids of you query there. All other joins use the merge
strategy. Is it correct, that the factorization has been completed before
the exception occurs? You can see that in the output if the 10th iteration
has been reached.

Maybe you can also send us the execution plan:
println(env.getExecutionPlan()).

What we could try is to insert a join hint for the respective join
operation and see whether this solves your problem.

Cheers,
Till
​

On Sat, Jun 6, 2015 at 1:32 AM Till Rohrmann <trohrmann@apache.org> wrote:

> I'll look into it to find the responsible join operation.
> On Jun 5, 2015 10:50 AM, "Stephan Ewen" <sewen@apache.org> wrote:
>
>> There are two different issues here:
>>
>> 1) Flink does figure out how much memory a join gets, but that memory may
>> be too little for the join to accept it. Flink plans highly conservative
>> right now - too conservative often, which is something we have on the
>> immediate roadmap to fix.
>>
>> 2) The "Hash Join exceeded recursions" problems is made worse by little
>> memory, but is usually an indicator that the join is running the wrong way
>> anyways. The side with many duplicates should rarely be the build side,
>> but
>> in most cases the probe side.
>>
>>
>> Stephan
>>
>>
>>
>>
>> On Fri, Jun 5, 2015 at 9:13 AM, Felix Neutatz <neutatz@googlemail.com>
>> wrote:
>>
>> > Shouldn't Flink figure it out on its own, how much memory there is for
>> the
>> > join?
>> >
>> > The detailed trace for the Nullpointer exception can be found here:
>> >
>> >
>> https://github.com/FelixNeutatz/IMPRO-3.SS15/blob/8b679f1c2808a2c6d6900824409fbd47e8bed826/NullPointerException.txt
>> >
>> > Best regards,
>> > Felix
>> >
>> > 2015-06-04 19:41 GMT+02:00 Till Rohrmann <till.rohrmann@gmail.com>:
>> >
>> > > I think it is not a problem of join hints, but rather of too little
>> > memory
>> > > for the join operator. If you set the temporary directory, then the
>> job
>> > > will be split in smaller parts and thus each operator gets more
>> memory.
>> > > Alternatively, you can increase the memory you give to the Task
>> Managers.
>> > >
>> > > The problem with the NullPointerException won't be solved by this,
>> > though.
>> > > Could you send the full stack trace for that?
>> > >
>> > > Cheers,
>> > > Till
>> > > On Jun 4, 2015 7:10 PM, "Andra Lungu" <lungu.andra@gmail.com> wrote:
>> > >
>> > > > Hi Felix,
>> > > >
>> > > > Passing a JoinHint to your function should help.
>> > > > see:
>> > > >
>> > > >
>> > >
>> >
>> http://mail-archives.apache.org/mod_mbox/flink-user/201504.mbox/%3CCANC1h_vFFbQyyiKTzCDPihn09r4HE4OLuiuRSJnci_rWc+cccA@mail.gmail.com%3E
>> > > >
>> > > > Cheers,
>> > > > Andra
>> > > >
>> > > > On Thu, Jun 4, 2015 at 7:07 PM, Felix Neutatz <
>> neutatz@googlemail.com>
>> > > > wrote:
>> > > >
>> > > > > after bug fix:
>> > > > >
>> > > > > for 100 blocks and standard jvm heap space
>> > > > >
>> > > > > Caused by: java.lang.RuntimeException: Hash join exceeded maximum
>> > > number
>> > > > of
>> > > > > recursions, without reducing partitions enough to be memory
>> resident.
>> > > > > Probably cause: Too many duplicate keys.
>> > > > > at
>> > > > >
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.hash.MutableHashTable.buildTableFromSpilledPartition(MutableHashTable.java:718)
>> > > > > at
>> > > > >
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.hash.MutableHashTable.prepareNextPartition(MutableHashTable.java:506)
>> > > > > at
>> > > > >
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.hash.MutableHashTable.nextRecord(MutableHashTable.java:543)
>> > > > > at
>> > > > >
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.hash.NonReusingBuildFirstHashMatchIterator.callWithNextKey(NonReusingBuildFirstHashMatchIterator.java:104)
>> > > > > at
>> > > >
>> > org.apache.flink.runtime.operators.MatchDriver.run(MatchDriver.java:173)
>> > > > > at
>> > > > >
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.RegularPactTask.run(RegularPactTask.java:496)
>> > > > > at
>> > > > >
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.RegularPactTask.invoke(RegularPactTask.java:362)
>> > > > > at org.apache.flink.runtime.taskmanager.Task.run(Task.java:559)
>> > > > > at java.lang.Thread.run(Thread.java:745)
>> > > > >
>> > > > >
>> > > > > for 150 blocks and 5G jvm heap space
>> > > > >
>> > > > > Caused by: java.lang.NullPointerException
>> > > > > at
>> > > > >
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.hash.HashPartition.spillPartition(HashPartition.java:310)
>> > > > > ...
>> > > > >
>> > > > > Best regards,
>> > > > > Felix
>> > > > >
>> > > > > 2015-06-04 10:19 GMT+02:00 Felix Neutatz <neutatz@googlemail.com
>> >:
>> > > > >
>> > > > > > Yes, I will try it again with the newest update :)
>> > > > > >
>> > > > > > 2015-06-04 10:17 GMT+02:00 Till Rohrmann <
>> till.rohrmann@gmail.com
>> > >:
>> > > > > >
>> > > > > >> If the first error is not fixed by Chiwans PR, then
we should
>> > > create a
>> > > > > >> JIRA
>> > > > > >> for it to not forget it.
>> > > > > >>
>> > > > > >> @Felix: Chiwan's PR is here [1]. Could you try to run
ALS again
>> > with
>> > > > > this
>> > > > > >> version?
>> > > > > >>
>> > > > > >> Cheers,
>> > > > > >> Till
>> > > > > >>
>> > > > > >> [1] https://github.com/apache/flink/pull/751
>> > > > > >>
>> > > > > >> On Thu, Jun 4, 2015 at 10:10 AM, Chiwan Park <
>> > chiwanpark@icloud.com
>> > > >
>> > > > > >> wrote:
>> > > > > >>
>> > > > > >> > Hi. The second bug is fixed by the recent change
in PR.
>> > > > > >> > But there is just no test case for first bug.
>> > > > > >> >
>> > > > > >> > Regards,
>> > > > > >> > Chiwan Park
>> > > > > >> >
>> > > > > >> > > On Jun 4, 2015, at 5:09 PM, Ufuk Celebi <uce@apache.org>
>> > wrote:
>> > > > > >> > >
>> > > > > >> > > I think both are bugs. They are triggered
by the different
>> > > memory
>> > > > > >> > > configurations.
>> > > > > >> > >
>> > > > > >> > > @chiwan: is the 2nd error fixed by your recent
change?
>> > > > > >> > >
>> > > > > >> > > @felix: if yes, can you try the 2nd run again
with the
>> > changes?
>> > > > > >> > >
>> > > > > >> > > On Thursday, June 4, 2015, Felix Neutatz <
>> > > neutatz@googlemail.com>
>> > > > > >> wrote:
>> > > > > >> > >
>> > > > > >> > >> Hi,
>> > > > > >> > >>
>> > > > > >> > >> I played a bit with the ALS recommender
algorithm. I used
>> the
>> > > > > >> movielens
>> > > > > >> > >> dataset:
>> > > > > >> > >>
>> > > > >
>> http://files.grouplens.org/datasets/movielens/ml-latest-README.html
>> > > > > >> > >>
>> > > > > >> > >> The rating matrix has 21.063.128 entries
(ratings).
>> > > > > >> > >>
>> > > > > >> > >> I run the algorithm with 3 configurations:
>> > > > > >> > >>
>> > > > > >> > >> 1. standard jvm heap space:
>> > > > > >> > >>
>> > > > > >> > >> val als = ALS()
>> > > > > >> > >>   .setIterations(10)
>> > > > > >> > >>   .setNumFactors(10)
>> > > > > >> > >>   .setBlocks(100)
>> > > > > >> > >>
>> > > > > >> > >> throws:
>> > > > > >> > >> java.lang.RuntimeException: Hash Join
bug in memory
>> > management:
>> > > > > >> Memory
>> > > > > >> > >> buffers leaked.
>> > > > > >> > >> at
>> > > > > >> > >>
>> > > > > >> > >>
>> > > > > >> >
>> > > > > >>
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.hash.MutableHashTable.buildTableFromSpilledPartition(MutableHashTable.java:733)
>> > > > > >> > >> at
>> > > > > >> > >>
>> > > > > >> > >>
>> > > > > >> >
>> > > > > >>
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.hash.MutableHashTable.prepareNextPartition(MutableHashTable.java:508)
>> > > > > >> > >> at
>> > > > > >> > >>
>> > > > > >> > >>
>> > > > > >> >
>> > > > > >>
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.hash.MutableHashTable.nextRecord(MutableHashTable.java:541)
>> > > > > >> > >> at
>> > > > > >> > >>
>> > > > > >> > >>
>> > > > > >> >
>> > > > > >>
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.hash.NonReusingBuildFirstHashMatchIterator.callWithNextKey(NonReusingBuildFirstHashMatchIterator.java:104)
>> > > > > >> > >> at
>> > > > > >> >
>> > > > >
>> > >
>> org.apache.flink.runtime.operators.MatchDriver.run(MatchDriver.java:173)
>> > > > > >> > >> at
>> > > > > >> > >>
>> > > > > >> > >>
>> > > > > >> >
>> > > > > >>
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.RegularPactTask.run(RegularPactTask.java:496)
>> > > > > >> > >> at
>> > > > > >> > >>
>> > > > > >> > >>
>> > > > > >> >
>> > > > > >>
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.RegularPactTask.invoke(RegularPactTask.java:362)
>> > > > > >> > >> at
>> > org.apache.flink.runtime.taskmanager.Task.run(Task.java:559)
>> > > > > >> > >> at java.lang.Thread.run(Thread.java:745)
>> > > > > >> > >>
>> > > > > >> > >> 2. 5G jvm heap space
>> > > > > >> > >>
>> > > > > >> > >> val als = ALS()
>> > > > > >> > >>   .setIterations(10)
>> > > > > >> > >>   .setNumFactors(10)
>> > > > > >> > >>   .setBlocks(150)
>> > > > > >> > >>
>> > > > > >> > >> throws:
>> > > > > >> > >>
>> > > > > >> > >> java.lang.NullPointerException
>> > > > > >> > >> at
>> > > > > >> > >>
>> > > > > >> > >>
>> > > > > >> >
>> > > > > >>
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.hash.HashPartition.spillPartition(HashPartition.java:310)
>> > > > > >> > >> at
>> > > > > >> > >>
>> > > > > >> > >>
>> > > > > >> >
>> > > > > >>
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.hash.MutableHashTable.spillPartition(MutableHashTable.java:1090)
>> > > > > >> > >> at
>> > > > > >> > >>
>> > > > > >> > >>
>> > > > > >> >
>> > > > > >>
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.hash.MutableHashTable.insertBucketEntry(MutableHashTable.java:923)
>> > > > > >> > >> at
>> > > > > >> > >>
>> > > > > >> > >>
>> > > > > >> >
>> > > > > >>
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.hash.MutableHashTable.buildTableFromSpilledPartition(MutableHashTable.java:779)
>> > > > > >> > >> at
>> > > > > >> > >>
>> > > > > >> > >>
>> > > > > >> >
>> > > > > >>
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.hash.MutableHashTable.prepareNextPartition(MutableHashTable.java:508)
>> > > > > >> > >> at
>> > > > > >> > >>
>> > > > > >> > >>
>> > > > > >> >
>> > > > > >>
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.hash.MutableHashTable.nextRecord(MutableHashTable.java:541)
>> > > > > >> > >> at
>> > > > > >> > >>
>> > > > > >> > >>
>> > > > > >> >
>> > > > > >>
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.hash.NonReusingBuildFirstHashMatchIterator.callWithNextKey(NonReusingBuildFirstHashMatchIterator.java:104)
>> > > > > >> > >> at
>> > > > > >> >
>> > > > >
>> > >
>> org.apache.flink.runtime.operators.MatchDriver.run(MatchDriver.java:173)
>> > > > > >> > >> at
>> > > > > >> > >>
>> > > > > >> > >>
>> > > > > >> >
>> > > > > >>
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.RegularPactTask.run(RegularPactTask.java:496)
>> > > > > >> > >> at
>> > > > > >> > >>
>> > > > > >> > >>
>> > > > > >> >
>> > > > > >>
>> > > > >
>> > > >
>> > >
>> >
>> org.apache.flink.runtime.operators.RegularPactTask.invoke(RegularPactTask.java:362)
>> > > > > >> > >> at
>> > org.apache.flink.runtime.taskmanager.Task.run(Task.java:559)
>> > > > > >> > >> at java.lang.Thread.run(Thread.java:745)
>> > > > > >> > >>
>> > > > > >> > >> 3. 14G jvm heap space
>> > > > > >> > >>
>> > > > > >> > >> val als = ALS()
>> > > > > >> > >>   .setIterations(10)
>> > > > > >> > >>   .setNumFactors(10)
>> > > > > >> > >>   .setBlocks(150)
>> > > > > >> > >>   .setTemporaryPath("/tmp/tmpALS")
>> > > > > >> > >>
>> > > > > >> > >> -> works
>> > > > > >> > >>
>> > > > > >> > >> Is this a Flink problem or is it just
my bad
>> configuration?
>> > > > > >> > >>
>> > > > > >> > >> Best regards,
>> > > > > >> > >> Felix
>> > > > > >> > >>
>> > > > > >> >
>> > > > > >> >
>> > > > > >> >
>> > > > > >> >
>> > > > > >> >
>> > > > > >> >
>> > > > > >>
>> > > > > >
>> > > > > >
>> > > > >
>> > > >
>> > >
>> >
>>
>

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