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From "James Taylor (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (PHOENIX-4051) Prevent out-of-order updates for mutable index updates
Date Wed, 02 Aug 2017 20:30:00 GMT

     [ https://issues.apache.org/jira/browse/PHOENIX-4051?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

James Taylor updated PHOENIX-4051:
----------------------------------
    Attachment: PHOENIX-4051_v3.patch

Can you give this patch a try, [~mujtabachohan]? Let me know if you need an 0.98 version of
the patch.

> Prevent out-of-order updates for mutable index updates
> ------------------------------------------------------
>
>                 Key: PHOENIX-4051
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-4051
>             Project: Phoenix
>          Issue Type: Bug
>            Reporter: James Taylor
>            Assignee: James Taylor
>         Attachments: PHOENIX-4051_v1.patch, PHOENIX-4051_v2.patch, PHOENIX-4051_v3.patch
>
>
> Out-of-order processing of data rows during index maintenance causes mutable indexes
to become out of sync with regard to the data table. Here's a simple example to illustrate
the issue:
> # Assume table T(K,V) and index X(V,K).
> # Upsert T(A, 1) at t10. Index updates: Put X(1,A) at t10.
> # Upsert T(A, 3) at t30. Index updates: Delete X(1,A) at t29, Put X(3,A) at t30.
> # Upsert T(A,2) at t20. Index updates: Delete X(1,A) at t19, Put X(2,A) at t20, Delete
X(2,A) at t29
> Ideally, we'd want to remove the Delete X(1,A) at t29 since this isn't correct in terms
of timeline consistency, but we can't do that with HBase without support for deleting/undoing
Delete markers. 
> The above is not what is occurring. Instead, when T(A,2) comes in, the Put X(2,A) will
occur at t20, but the Delete won't occur. This causes more index rows than data rows, essentially
making it invalid.
> A quick fix is to reset the timestamp of the data table mutations to the current time
within the preBatchMutate call, when the row is exclusively locked. This skirts the issue
because then timestamps won't overlap.



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