[jira] [Created] (NIFI-3332) Bug in ListXXX causes matching timestamps to be ignored on later runs

["Joe Skora (JIRA)" <ji...@apache.org>]

Joe Skora created NIFI-3332:
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             Summary: Bug in ListXXX causes matching timestamps to be ignored on later runs
                 Key: NIFI-3332
                 URL: https://issues.apache.org/jira/browse/NIFI-3332
             Project: Apache NiFi
          Issue Type: Bug
          Components: Core Framework
    Affects Versions: 1.1.1, 0.7.1
            Reporter: Joe Skora
            Priority: Critical
         Attachments: Test-showing-ListFile-timestamp-bug.log, Test-showing-ListFile-timestamp-bug.patch

The new state implementation for the ListXXX processors based on AbstractListProcessor creates a race conditions when processor runs occur while a batch of files is being written with the same timestamp.

The changes to state management dropped tracking of the files processed for a given timestamp.  Without the record of files processed, the remainder of the batch is ignored on the next processor run since their timestamp is not greater than the one timestamp stored in processor state.  With the file tracking it was possible to process files that matched the timestamp exactly and exclude the previously processed files.

A basic time goes as follows.
  T0 - system creates or receives batch of files with Tx timestamp where Tx is more than the current timestamp in processor state.
  T1 - system writes 1st half of Tx batch to the ListFile source directory.
  T2 - ListFile runs picking up 1st half of Tx batch and stores Tx timestamp in processor state.
  T3 - system writes 2nd half of Tx batch to ListFile source directory.
  T4 - ListFile runs ignoring any files with T <= Tx, eliminating 2nd half Tx timestamp batch.

I've attached a patch[1] for TestListFile.java that adds an instrumented unit test demonstrates the problem and a log[2] of the output from one such run.  The test writes 3 files each in two batches with processor runs after each batch.  Batch 2 writes files with timestamps older than, equal to, and newer than the timestamp stored when batch 1 was processed, but only the newer file is picked up.  The older file is correctly ignored but file with the matchin timestamp file should have been processed.

[1] Test-showing-ListFile-timestamp-bug.patch
[2] Test-showing-ListFile-timestamp-bug.log



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