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https://issues.apache.org/jira/browse/PHOENIX-6888?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17702376#comment-17702376
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ASF GitHub Bot commented on PHOENIX-6888:
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kadirozde commented on PR #1569:
URL: https://github.com/apache/phoenix/pull/1569#issuecomment-1475410159
> I am not done yet. I implemented everything that I planned. I may need to
enhance TTL masking to cover one more case where an expired row revives between
compactions. I also need add more comments and possibly more tests. There are
still some test failures to address too.
I have addressed all comments provided so far, fixed test failures and
introduced new tests to cover the code. The PR is now finalized. I also added a
config param to disable the behavior at the cluster level when needed.
@apurtell, @stoty, @gjacoby126, @jpisaac
> Fixing TTL and Max Lookback Issues for Phoenix Tables
> -----------------------------------------------------
>
> Key: PHOENIX-6888
> URL: https://issues.apache.org/jira/browse/PHOENIX-6888
> Project: Phoenix
> Issue Type: Bug
> Affects Versions: 5.1.3
> Reporter: Kadir Ozdemir
> Assignee: Kadir Ozdemir
> Priority: Major
>
> In HBase, the unit of data is a cell and data retention rules are executed at
> the cell level. These rules are defined at the column family level. Phoenix
> leverages the data retention features of HBase and exposes them to its users
> to provide its TTL feature at the table level. However, these rules (since
> they are defined at the cell level instead of the row level) results in
> partial row retention that in turn creates data integrity issues at the
> Phoenix level.
> Similarly, Phoenix’s max lookback feature leverages HBase deleted data
> retention capabilities to preserve deleted cells within a configurable max
> lookback. This requires two data retention windows, max lookback and TTL. One
> end of these windows is the current time and the end is a moment in the past
> (i.e., current time minus the window size). Typically, the max lookback
> window is shorter than the TTL window. In the max lookback window, we would
> like to preserve the complete history of mutations regardless of how many
> cell versions these mutations generated. In the remaining TTL window outside
> the max lookback, we would like to apply the data retention rules defined
> above. However, HBase provides only one data retention window. Thus, the max
> lookback window had to be extended to become TTL window and the max lookback
> feature results in unwantedly retaining deleted data for the maximum of max
> lookback and TTL periods.
> This Jira is to fix both of these issues.
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