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https://issues.apache.org/jira/browse/PHOENIX-5082?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16729777#comment-16729777
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Ohad Shacham commented on PHOENIX-5082:
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Hi [~lhofhansl],
Thanks for your tests and comments, we'll go over everything and fix.
Regarding 8. As far as I see you upserted 400K rows without committing the
transaction and then ran count from a different client.
Omid does read the shadow cells together with the cells themselves. However,
when the shadow cell does not exists, Omid needs to check the commit table. In
case the transaction commit does not exists in there as well then another
search for the shadow cell needs to be done.
This is needed to avoid cases where the post commit of client I updated the
shadow cells after client II read it at the first time and the same post commit
removed the entry from the commit table right before client II accessed the
commit table.
In order to avoid this, we will need to leave the commit entries at the commit
table and GC them once in a while. This will also require some invariant
guarantee though.
6. Omid can write, we just batch these from performance issues, this can be
fixed though. We just need to guarantee that all data exists in HBase before
send commit request to the TSO.
9. seems like a bug.
BTW, did you check the low latency version? It does not require batch write to
commit table from the TSO and can help with the degradation you experienced.
Sorry for the late response, we are on vacation and return to work on Sunday.
Thanks!
Ohad
> Observations about the Phoenix-Omid integration
> -----------------------------------------------
>
> Key: PHOENIX-5082
> URL: https://issues.apache.org/jira/browse/PHOENIX-5082
> Project: Phoenix
> Issue Type: Task
> Reporter: Lars Hofhansl
> Assignee: Yonatan Gottesman
> Priority: Major
> Attachments: CommitTS-Sample.png, Omid-profile.png, Omid-sample.png
>
>
> Filing this issue to track my observations and perhaps some fixes.
> [~ohads]
> [~jamestaylor]
> [~yonigo]
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