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https://issues.apache.org/jira/browse/NIFI-4775?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Brandon DeVries updated NIFI-4775:
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    Attachment: rocksdb-flowfile-repo.adoc

> Allow FlowFile Repository to optionally perform fsync when writing CREATE 
> events but not other events
> -----------------------------------------------------------------------------------------------------
>
>                 Key: NIFI-4775
>                 URL: https://issues.apache.org/jira/browse/NIFI-4775
>             Project: Apache NiFi
>          Issue Type: Improvement
>          Components: Core Framework
>            Reporter: Mark Payne
>            Assignee: Brandon DeVries
>            Priority: Major
>         Attachments: rocksdb-flowfile-repo.adoc
>
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> Currently, when a FlowFile is written to the FlowFile Repository, the repo 
> can either fsync or not, depending on nifi.properties. We should allow a 
> third option, of fsync only for CREATE events. In this case, if we receive 
> new data from a source we can fsync the update to the FlowFile Repository 
> before ACK'ing the data from the source. This allows us to guarantee data 
> persistence without the overhead of an fsync for every FlowFile Repository 
> update.
> It may make sense, though, to be a bit more selective about when do this. For 
> example if the source is a system that does not allow us to acknowledge the 
> receipt of data, such as a ListenUDP processor, this doesn't really buy us 
> much. In such a case, we could be smart about avoiding the high cost of an 
> fsync. However, for something like GetSFTP where we have to remove the file 
> in order to 'acknowledge receipt' we can ensure that we wait for the fsync 
> before proceeding.



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