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https://issues.apache.org/jira/browse/ARROW-12030?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17441374#comment-17441374
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Weston Pace commented on ARROW-12030:
-------------------------------------
This is superseded by ARROW-14648 which I just wrote now that I have more run
time / experience with backpressure and readahead.
Per [~apitrou] 's comment earlier, it is better to have a limit specified by
the user than to automatically base it on available RAM.
There will still likely be a need for a single "plan-level" limit at some point
but that can come later.
> [C++] Change dataset readahead to be based on available RAM/CPU instead of
> fixed constants/options
> --------------------------------------------------------------------------------------------------
>
> Key: ARROW-12030
> URL: https://issues.apache.org/jira/browse/ARROW-12030
> Project: Apache Arrow
> Issue Type: Improvement
> Components: C++
> Reporter: Weston Pace
> Assignee: Weston Pace
> Priority: Major
>
> Right now in the dataset scanning there are a few places where we add
> readahead. At each spot we have to pick some max for how much we read ahead.
> Instead of trying to figure out some max it might be nicer to base it on the
> available RAM.
> On the other hand, it may be the case that there is some set of nice
> constants that just always works so this can probably wait until we
> understand more the memory usage of dataset scanning.
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