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https://issues.apache.org/jira/browse/IMPALA-5013?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Tim Armstrong resolved IMPALA-5013.
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Resolution: Done
Fix Version/s: Not Applicable
With IMPALA-7349 the estimate is a guess at the "ideal" memory required to
execute the query with full performance.
> Re-evaluate our approach to per-operator memory estimates
> ---------------------------------------------------------
>
> Key: IMPALA-5013
> URL: https://issues.apache.org/jira/browse/IMPALA-5013
> Project: IMPALA
> Issue Type: Improvement
> Components: Frontend
> Affects Versions: Impala 2.8.0
> Reporter: Tim Armstrong
> Priority: Major
> Labels: resource-management
> Fix For: Not Applicable
>
>
> The way that memory estimates are computed for PlanNodes and Sinks are ad-hoc
> and in some cases much less accurate than they could be. We should clarify
> what the memory estimates mean, how they should be computed and then
> systematically fix them.
> In general it's difficult to produce accurate memory estimates, because it
> depends on having accurate estimates of cardinality and other runtime
> parameters, so this JIRA isn't meant to guarantee any specific level of
> accuracy of estimates, just to generally improve the estimates and clarify
> what they mean and how they should be calculated
> We should also consider deprecating or removing these estimates, unless they
> are useful for computing "ideal" memory in IMPALA-3706.
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