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https://issues.apache.org/jira/browse/NIFI-4715?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16309489#comment-16309489
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ASF GitHub Bot commented on NIFI-4715:
--------------------------------------
Github user ijokarumawak commented on the issue:
https://github.com/apache/nifi/pull/2361
@adamlamar How long do you think you need to address multiple bugs you are
aware of? If those can be addressed in the same ListS3 processor, then I'd
prefer to have all (as much as we can) in this JIRA/PR, as we can reduce
testing effort and overall review cycle. If it's too complicated to be done at
once, then please submit different JIRAs to beak those into smaller pieces.
Thank you!
> ListS3 produces duplicates in frequently updated buckets
> --------------------------------------------------------
>
> Key: NIFI-4715
> URL: https://issues.apache.org/jira/browse/NIFI-4715
> Project: Apache NiFi
> Issue Type: Bug
> Components: Core Framework
> Affects Versions: 1.2.0, 1.3.0, 1.4.0
> Environment: All
> Reporter: Milan Das
> Attachments: List-S3-dup-issue.xml, screenshot-1.png
>
>
> ListS3 state is implemented using HashSet. HashSet is not thread safe. When
> ListS3 operates in multi threaded mode, sometimes it tries to list same
> file from S3 bucket. Seems like HashSet data is getting corrupted.
> currentKeys = new HashSet<>(); // need to be implemented Thread Safe like
> currentKeys = //ConcurrentHashMap.newKeySet();
> *{color:red}+Update+{color}*:
> This is not a HashSet issue:
> Root cause is:
> When the file gets uploaded to S3 simultaneously when List S3 is in progress.
> onTrigger--> maxTimestamp is initiated as 0L.
> This is clearing keys as per the code below
> When lastModifiedTime on S3 object is same as currentTimestamp for the listed
> key it should be skipped. As the key is cleared, it is loading the same file
> again.
> I think fix should be to initiate the maxTimestamp with currentTimestamp not
> 0L.
> {code}
> long maxTimestamp = currentTimestamp;
> {code}
> Following block is clearing keys.
> {code:title=org.apache.nifi.processors.aws.s3.ListS3.java|borderStyle=solid}
> if (lastModified > maxTimestamp) {
> maxTimestamp = lastModified;
> currentKeys.clear();
> getLogger().debug("clearing keys");
> }
> {code}
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