Yuanhao Zhu created NIFI-13340:
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Summary: Flowfiles stopped to be ingested before a processor group
Key: NIFI-13340
URL: https://issues.apache.org/jira/browse/NIFI-13340
Project: Apache NiFi
Issue Type: Bug
Components: Core Framework
Affects Versions: 1.25.0
Environment: Host OS :ubuntu 20.04 in wsl
CPU: Intel(R) Xeon(R) Platinum 8370C CPU @ 2.80GHz
RAM: 128GB
ZFS ARC cache was configured to be maximum 4 GB
Reporter: Yuanhao Zhu
Attachments: image-2024-06-03-14-42-37-280.png,
image-2024-06-03-14-44-15-590.png
*Background:* We run nifi as a standalone instance in a docker container in on
all our stages, the statemanagement provider used by our instance is the local
WAL backed provider.
{*}Description{*}: We observed that the flowfiles in front of one of our
processor groups stopped to be ingested once in a while and it happens on all
our stages without noticeable pattern. The flowfile concurrency policy of the
processor group that stopped ingesting data is set to SINGLE_BATCH_PER_NODE and
the outbound policy is set to BATCH_OUTPUT. The ingestion should continue since
the processor group had already send out every flowfile in it, but it stopped.
There is only one brutal solution from our side(We have to manually switch the
flowfile concurrency to unbounded and then switch it back to make it work
again) and the occurrence of this issue had impacted our data ingestion.
!image-2024-06-03-14-42-37-280.png!
!image-2024-06-03-14-44-15-590.png!
As you can see in the screenshot that the processor group 'Delete before
Insert' has no more flowfile to output but still it does not ingest the data
queued in the input port
In the log file I found the following:
{color:#FF0000}2024-06-03 11:34:01,772 TRACE [Timer-Driven Process Thread-15]
o.apache.nifi.groups.StandardDataValve Will not allow data to flow into
StandardProcessGroup[identifier=5eb0ad69-e8ed-3ba0-52da-af94fb9836cd,name=Delete
before Insert] because Outbound Policy is Batch Output and valve is already
open to allow data to flow out of group{color}
Also in the diagnostics, I found the following for the 'Delete before Insert'
processor group:
Process Group e6510a87-aa78-3268-1b11-3c310f0ad144, Name = Search and Delete
existing reports(This is the parent processor group of the Delete before Insert)
Currently Have Data Flowing In: []
{color:#FF0000}Currently Have Data Flowing Out:
[StandardProcessGroup[identifier=5eb0ad69-e8ed-3ba0-52da-af94fb9836cd,name=Delete
before Insert]]{color}
Reason for Not allowing data to flow in:
Data Valve is already allowing data to flow out of group:
StandardProcessGroup[identifier=5eb0ad69-e8ed-3ba0-52da-af94fb9836cd,name=Delete
before Insert]
Reason for Not allowing data to flow out:
Output is Allowed:
StandardProcessGroup[identifier=5eb0ad69-e8ed-3ba0-52da-af94fb9836cd,name=Delete
before Insert]
Which is clearly {*}not correct{*}. since there are currently not data flowing
out from the 'Delete before Insert' processor group.
We dig through the source code of StandardDataValve.java and found that that
data valve's states are stored every time the data valve is opened and close so
the potential reason causing this issue is that the processor group id was put
into the statemap when data flowed in but somehow the removal of the entry was
not successful. We are aware that if the statemap is not stored before the nifi
restarts, it could lead to such circumstances, but in the recent occurrences of
this issue, there were not nifi restart recorded or observed at the time when
all those flowfiles started to queue in front of the processor group
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