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https://issues.apache.org/jira/browse/ACCUMULO-1188?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Keith Turner updated ACCUMULO-1188:
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Attachment: ACCUMULO-1188_fig1.png
I was thinking about how this could be done and had the following thoughts :
* A tablet should advertise different ports for reading and writing, so that
reader can go directly to the process running scans.
* The process running the scan should also contain the cache.
I attached fig 1 that shows the data flows I was thinking of. I have also
started to think that we should not pursue this approach or running compactions
and scans in separate processes.
I think that if ACCUMULO-1454 is implemented, that it may solve the problem
this ticket is trying to solve. If an iterator gets stuck in an infinite loop
ACCUMULO-1454 makes it possible to restart the tserver and avoid disruption.
I am thinking the following should be done.
* Use ACCUMULO-1345 and ACCUMULO-1454 to restart tservers with stuck
compactions/scans.
* Need to blacklist tablets that repeatedly fail ACCUMULO-1570
Is there any reason to pursue this ticket if we restart tservers and blacklist
tablets? Even if we run user iterators in a separate process, we will still
need to blacklist tablets and restart those separate processes. The only thing
its seems to help with is avoiding walog recovery. Are there other benefits?
> Sandbox iterators
> -----------------
>
> Key: ACCUMULO-1188
> URL: https://issues.apache.org/jira/browse/ACCUMULO-1188
> Project: Accumulo
> Issue Type: Bug
> Reporter: Keith Turner
> Fix For: 1.6.0
>
> Attachments: ACCUMULO-1188_fig1.png
>
>
> It's possible that a user iterator can bring down a tablet server. For
> example if it has an OOM or creates too many threads. It would be nice if
> iterators could be sandboxed in some way.
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