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https://issues.apache.org/jira/browse/IMPALA-6964?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sahil Takiar resolved IMPALA-6964.
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       Resolution: Fixed
    Fix Version/s: Impala 3.2.0

> Track stats about column and page sizes in Parquet reader
> ---------------------------------------------------------
>
>                 Key: IMPALA-6964
>                 URL: https://issues.apache.org/jira/browse/IMPALA-6964
>             Project: IMPALA
>          Issue Type: Improvement
>          Components: Backend
>            Reporter: Tim Armstrong
>            Assignee: Sahil Takiar
>            Priority: Major
>              Labels: observability, parquet, ramp-up
>             Fix For: Impala 3.2.0
>
>
> It would be good to have stats for scanned parquet data about page sizes. We 
> currently can't tell much about the "shape" of the parquet pages from the 
> profile. Some questions that are interesting:
> * How big is each column? I.e. total compressed and decompressed size read.
> * How big are pages on average? Either compressed or decompressed size
> * What is the compression ratio for pages? Could be inferred from the above 
> two.
> I think storing all the stats in the profile per-column would be too much 
> data, but we could probably infer most useful things from higher-level 
> aggregates.



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