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https://issues.apache.org/jira/browse/MAHOUT-1802?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15186456#comment-15186456
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ASF GitHub Bot commented on MAHOUT-1802:
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Github user asfgit closed the pull request at:
https://github.com/apache/mahout/pull/185
> Capture attached checkpoints (if cached)
> -----------------------------------------
>
> Key: MAHOUT-1802
> URL: https://issues.apache.org/jira/browse/MAHOUT-1802
> Project: Mahout
> Issue Type: Improvement
> Affects Versions: 0.11.1
> Reporter: Andrew Palumbo
> Assignee: Andrew Palumbo
> Fix For: 0.11.2
>
>
> Currently, the optimizer generates checkpoints and attaches them to actual
> logical elements of the DAG via CheckpointAction$cp.
> the way it worsk today is as follows:
> {code}
> drmC = drmA+ drmB
> val cp1 = drmC.checkpoint() // checkpoint
> val cp2 = drmC.checkpoint() // cp2 == cp1
> drmD = cp1 + drmE // cp1 + drmE
> {code}
> but, in:
> {code}
> drmD = drmC + drmE // computes drmA + drmB + drmC all over
> {code}
> {{drmC}} already has {{cp1}} attached to it so we should assume the common
> computational path is the intent here regardless and should be used, instead
> of building plans that recompute it. That is,
> {{drmD = drmC + drmE}} should imply {{cp1 + drmE}} as well even if checkpoint
> is not used explicitly.
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