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From Jungdae Kim <kjd9...@gmail.com>
Subject Re: AW: Duplicate Records Showing in Apache Phoenix
Date Thu, 08 Mar 2018 09:16:40 GMT
Hello, Azharuddin.

I have experienced the same issue with Phoenix 4.9.0.

Did you have this issues for the tables that have TTL property or in which
many rows are updated or removed frequently?

In my case,  i figured out that in Phoenix, parallel scans make duplicate
rows, when all regions including the last region after the region that
include a last guidepost, have no guideposts.

The reason for duplicates is that some scans has overlapping scan ranges
from the last guide post in a table to the end key of the last region, by
phoenix bug, in the condition that i already mentioned.
A attached slide describes this issue in detail.

I think you might suffer from the same problem by this bug, because the
issue has not occurred when table has no guideposts by increasing guidepost
with or deleting system.stats.
If you want to make sure this bug causes duplicates, decrease guidepost
width to make guideposts, and check whether last region includes last
guidepost for the table or not. if not, duplicate issue caused by this bug.

To solve this issue, you have to apply a patch for Phoenix 4.7.0 or upgrade
Phoenix version to 4.12.0 or higher.
If you want to apply a patch to your phoenix, please refer to PHOENIX-4007
or a patch file i attached.

I hope my comments is helpful to you.

Regards
JeongDae Kim


김정대 드림.


On Mon, Mar 5, 2018 at 10:12 PM, Azharuddin Shaikh <
azharuddin.shaikh@resilinc.com> wrote:

> Thanks Martin for your reply.
>
> Actually after deleting system.stats also we are getting the same issue
> after few hours. It is occurring continuously.
>
> As of now, we have increased the guidepost width from 100MB to 5GB post
> which issue has not occurred but we are not confidence whether this is the
> exact solution to this problem.
>
> Let us know if there is any other specific solution to this problem and is
> there any trigger point to this issue.
>
>
>
> --
> Sent from: http://apache-phoenix-user-list.1124778.n5.nabble.com/
>

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