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From Joe Witt <joe.w...@gmail.com>
Subject Re: NiFi stops processing further flowfiles
Date Sat, 25 Nov 2017 03:05:25 GMT
Panos

In looking at the previously attached stack dump it looks as though the
provenance repository might be in a live lock state with one of its
threads.  The getSize call it is sitting on has been seen before and fixed
for some cases but perhaps not all.  There is a whole new provenance
repository you could switch to though which offers far faster and possibly
more stable behavior called the 'WriteAheadProvenanceRepository'.  You can
switch to it and it will honor the old data I believe.  To switch you just
edit your nifi.properties file and where it said
'PersistentProvenanceRepository' you change that classname to
'WriteAheadProvenanceRepository'.

Thanks
Joe

On Fri, Nov 24, 2017 at 1:59 PM, Juan Sequeiros <hellojuan@gmail.com> wrote:

> Hi Panos,
>
> The scheduling strategy defaults to timer driven on processors and I've
> always avoided using event driven so if you are not purposely using it I
> would just leave that setting alone. It even warns you that it is
> experimental.
>
> Your thread count is shown on the UI or can be called through RestApi
> /nifi-api/flow/status
>
> Thanks,
>
> Juan
>
> On Fri, Nov 24, 2017 at 1:24 PM Panos Geo <panospanos1983@outlook.com>
> wrote:
>
>> Thanks for your reply Juan.
>>
>>
>> I have been using NiFi for almost 2 years now and didn't know about this
>> setting. I 'll try to increase it and see what happens 😊
>>
>>
>> Does it also make sense to increase the "Maximum Event Driven Thread
>> Count"?
>>
>>
>> Finally, is there a way to monitor thread usage within NiFi?
>>
>>
>> Many thanks,
>>
>> Panos
>>
>>
>>
>> ------------------------------
>> *From:* Juan Sequeiros <hellojuan@gmail.com>
>> *Sent:* Friday, November 24, 2017 4:50 PM
>> *To:* users@nifi.apache.org
>> *Subject:* Re: NiFi stops processing further flowfiles
>>
>> Good afternoon,
>>
>> My quick guess is you are running out of threads.
>> If your system can handle it increase the default "max thread" count
>> found:
>>
>> Left side controller settings > Maximum timer driven thread count
>>
>> On Fri, Nov 24, 2017 at 10:47 AM Panos Geo <panospanos1983@outlook.com>
>> wrote:
>>
>> Hello all,
>>
>> We are running NiFi in a docker container that has roughly 500 processors
>> running. These include consuming messages (MQTT), interaction with a
>> database and some data processing with execute scripts. Our NiFi version is
>> v.1.4.0 and this instance has 18GB of RAM with 12GB allocated to Java heap.
>>
>> Quite recently we increased the load of the incoming messages
>> (1000messages/minute) that lead to more files being queued and some
>> backpressure. We then have experienced what appears to be some kind of
>> deadlock. NiFi stops processing any flowfiles and the processors running
>> get stuck (there is a thread running constantly; we see 1 at the top right
>> corner of the processor). If we try to stop these processors the icon gets
>> changed to stop, but we now have 2 threads stuck at the top right corner of
>> the processor. We cannot start these processors again and no other data
>> flow is being processed unless we restart NiFi. We have experienced this
>> multiple times over the past week.
>>
>> I am attaching a nifi dump in case it helps. Our nifi.properties is
>> fairly standard (we just have smaller retention periods for content and
>> provenance).
>>
>> Any thoughts? What can we do to debug this further?
>>
>> Many thanks,
>> Panos
>>
>>

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