[jira] [Work logged] (GOBBLIN-1778) Add house keeping thread in DagManager to periodically sync in memory state with mysql table

["ASF GitHub Bot (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/GOBBLIN-1778?focusedWorklogId=843331&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-843331 ]

ASF GitHub Bot logged work on GOBBLIN-1778:
-------------------------------------------

                Author: ASF GitHub Bot
            Created on: 02/Feb/23 23:02
            Start Date: 02/Feb/23 23:02
    Worklog Time Spent: 10m 
      Work Description: ZihanLi58 opened a new pull request, #3635:
URL: https://github.com/apache/gobblin/pull/3635

   Dear Gobblin maintainers,
   
   Please accept this PR. I understand that it will not be reviewed until I have checked off all the steps below!
   
   
   ### JIRA
   - [ ] My PR addresses the following [Gobblin JIRA](https://issues.apache.org/jira/browse/GOBBLIN/) issues and references them in the PR title. For example, "[GOBBLIN-XXX] My Gobblin PR"
       - https://issues.apache.org/jira/browse/GOBBLIN-1778
   
   
   ### Description
   - [ ] Here are some details about my PR, including screenshots (if applicable):
   Now dag managers have the assumption that it is the only process that can update mysql table and the in-memory state is always in sync with mysql. But we do notice that during the leader transforms period, it's possible that two dag manager can run concurrently and update the mysql db at the same time. 
   
   To address that, we need either add a lock to make sure only one dag manager is working at one time, or we need to have a housekeeping thread to periodically sync the in-memory state with the mysql table. After discussion, we choose to go with the later approach and we do have the assumption that GaaS submit jobs without specifying job.id, so jobs with same flow execution id will not share the staging dir and can be executed concurrently. 
   
   Besides that, during adding test, I figure out there will be NPE if we try to set the dag manager as inactive, add a small fix for that as well. 
   
   
   ### Tests
   - [ ] My PR adds the following unit tests __OR__ does not need testing for this extremely good reason:
   Just add a single thread for housekeeping so will not affect other functions. Also add unit test to make sure we close the thread when de-active DagManager to avoid memory leak 
   
   ### Commits
   - [ ] My commits all reference JIRA issues in their subject lines, and I have squashed multiple commits if they address the same issue. In addition, my commits follow the guidelines from "[How to write a good git commit message](http://chris.beams.io/posts/git-commit/)":
       1. Subject is separated from body by a blank line
       2. Subject is limited to 50 characters
       3. Subject does not end with a period
       4. Subject uses the imperative mood ("add", not "adding")
       5. Body wraps at 72 characters
       6. Body explains "what" and "why", not "how"
   
   




Issue Time Tracking
-------------------

            Worklog Id:     (was: 843331)
    Remaining Estimate: 0h
            Time Spent: 10m

> Add house keeping thread in DagManager to periodically sync in memory state with mysql table 
> ---------------------------------------------------------------------------------------------
>
>                 Key: GOBBLIN-1778
>                 URL: https://issues.apache.org/jira/browse/GOBBLIN-1778
>             Project: Apache Gobblin
>          Issue Type: Improvement
>            Reporter: Zihan Li
>            Priority: Major
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> Now dag managers have the assumption that it is the only process that can update mysql table and the in-memory state is always in sync with mysql. But we do notice that during the leader transforms period, it's possible that two dag manager can run concurrently and update the mysql db at the same time. 
> To address that, we need either add a lock to make sure only one dag manager is working at one time, or we need to have a housekeeping thread to periodically sync the in-memory state with the mysql table. After discussion, we choose to go with later approach



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