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From "Uwe L. Korn" <uw...@xhochy.com>
Subject Re: Which perform better JSON or convert JSON to parquet format ?
Date Thu, 14 Jun 2018 15:19:02 GMT
Hello,

you can also use Python wrapper pyarrow to create nested/json-like structures in Python. For
example using `pyarrow.array([[1, 2], [1], None, [12, 23, 23]])`. 

Cheers
Uwe

On Tue, Jun 12, 2018, at 4:45 PM, Lee, David wrote:
> Python supports tabular structures using pyarrow.
> 
> https://arrow.apache.org/docs/python/generated/pyarrow.schema.html
> 
> For nested structures like JSON you have to use C++ (parquet-cpp)
> 
> https://github.com/apache/parquet-cpp
> 
> We need more APIs developed to create nested JSON..
> 
> -----Original Message-----
> From: Divya Gehlot [mailto:divya.htconex@gmail.com] 
> Sent: Tuesday, June 12, 2018 5:25 AM
> To: user@drill.apache.org
> Subject: Re: Which perform better JSON or convert JSON to parquet format ?
> 
> [EXTERNAL EMAIL]
> 
> 
> Hi David,
> How to create the schema first using parquet library ?
> Can you please give an example?
> 
> Thanks,
> Divya
> 
> On Tue, 12 Jun 2018 at 00:03, Lee, David <David.Lee@blackrock.com> wrote:
> 
> > Parquet is faster especially if you are only looking for a subset of 
> > json objects. Every JSON key / array is treated as a column.
> >
> > With that said creating parquet from JSON is not bullet proof if you 
> > have really complex json which may have NULL values or many optional 
> > keys (Drill can't figure out what data type a NULL JSON value is and 
> > has trouble merging optional keys after sampling the first 20,000? 
> > records)
> >
> > If you are creating parquet you should be using the parquet libraries 
> > to define a consistent schema first. I've pretty much given up trying 
> > to create parquet from json which always ends in index out of bound 
> > (server
> > crashing) errors when trying to query parquet.
> >
> > -----Original Message-----
> > From: Ted Dunning [mailto:ted.dunning@gmail.com]
> > Sent: Monday, June 11, 2018 4:47 AM
> > To: user <user@drill.apache.org>
> > Subject: Re: Which perform better JSON or convert JSON to parquet format ?
> >
> > [EXTERNAL EMAIL]
> >
> >
> > Yes. Drill is good at JSON.
> >
> > But Parquet will be faster during a scan.
> >
> > Faster may be better. Or other things may be more important.
> >
> > You have to decide what is important to you. The great virtue of drill 
> > is that you have the choice.
> >
> >
> >
> > On Mon, Jun 11, 2018 at 11:06 AM Divya Gehlot 
> > <divya.htconex@gmail.com>
> > wrote:
> >
> > > Thanks to all for  your opinions !
> > > As Drill has been popularised  as complex JSON reader as compare to 
> > > other tools in space .
> > > Was wondering does drill works better for JSON rather than parquet.
> > >
> >
> >
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