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https://issues.apache.org/jira/browse/PARQUET-1542?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Wang, Gang updated PARQUET-1542:
--------------------------------
    Description: 
Currently in method readFooter of class ParquetFileReader, it will invoke 
method *converter.readParquetMetadata.* To decode file metadata,  there may be 
quite a number of times of IO processing underlying, which may heavily slow 
down parquet read performance.

A better way is to read all the footer bytes in a single IO, since we have 
already got footer length before, and pass down all the bytes to underlying*.*

 

And we have a test in our environment, this change may bring  50 percent 
improvement for some cases.

 

  was:
Currently in method readFooter of class ParquetFileReader, it will invoke 
method *converter.readParquetMetadata.* To decode file metadata,  there may be 
** quite a number of times of IO processing underlying, which may heavily slow 
down parquet read performance.

A better way is to read all the footer bytes in a single IO, since we have 
already got footer length before, and pass down all the bytes to underlying*.*

 

And we have a test in our environment, this change may bring  50 percent 
improvement for some cases.

 


> Merge multiple IO to one time IO in method readFooter
> -----------------------------------------------------
>
>                 Key: PARQUET-1542
>                 URL: https://issues.apache.org/jira/browse/PARQUET-1542
>             Project: Parquet
>          Issue Type: Improvement
>          Components: parquet-mr
>            Reporter: Wang, Gang
>            Priority: Major
>
> Currently in method readFooter of class ParquetFileReader, it will invoke 
> method *converter.readParquetMetadata.* To decode file metadata,  there may 
> be quite a number of times of IO processing underlying, which may heavily 
> slow down parquet read performance.
> A better way is to read all the footer bytes in a single IO, since we have 
> already got footer length before, and pass down all the bytes to underlying*.*
>  
> And we have a test in our environment, this change may bring  50 percent 
> improvement for some cases.
>  



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