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Posted to issues@kudu.apache.org by "Mike Percy (JIRA)" <ji...@apache.org> on 2018/09/14 20:03:00 UTC

[jira] [Updated] (KUDU-2562) Checkpoint highest legal timestamp in tablet superblock when tablet history GC deletes data

     [ https://issues.apache.org/jira/browse/KUDU-2562?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Mike Percy updated KUDU-2562:
-----------------------------
    Description: 
Checkpoint the highest legal timestamp in the tablet superblock when tablet history GC deletes data so that increasing the AHM age doesn’t expose us to inconsistent scans after a GC.

This is a real edge case and is a temporary condition depending on users restarting with a changed configuration flag. However without this safety feature, users can get bad scans if they increase the {{[--tablet_history_max_age_sec|http://kudu.apache.org/docs/configuration_reference.html#kudu-tserver_tablet_history_max_age_sec]}} command-line flag after a GC operation runs.

  was:
Checkpoint the highest legal timestamp in the tablet superblock when tablet history GC deletes data so that increasing the AHM age doesn’t expose us to inconsistent scans after a GC.

This is a real edge case and is a temporary condition depending on users restarting with a changed configuration flag. However without this safety feature, users can get bad scans if they change the flag.


> Checkpoint highest legal timestamp in tablet superblock when tablet history GC deletes data
> -------------------------------------------------------------------------------------------
>
>                 Key: KUDU-2562
>                 URL: https://issues.apache.org/jira/browse/KUDU-2562
>             Project: Kudu
>          Issue Type: Improvement
>          Components: tablet
>    Affects Versions: 1.7.1
>            Reporter: Mike Percy
>            Priority: Minor
>
> Checkpoint the highest legal timestamp in the tablet superblock when tablet history GC deletes data so that increasing the AHM age doesn’t expose us to inconsistent scans after a GC.
> This is a real edge case and is a temporary condition depending on users restarting with a changed configuration flag. However without this safety feature, users can get bad scans if they increase the {{[--tablet_history_max_age_sec|http://kudu.apache.org/docs/configuration_reference.html#kudu-tserver_tablet_history_max_age_sec]}} command-line flag after a GC operation runs.



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