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At work, we use Parquet (https://parquet.apache.org/ https://parquet.apache.org/) for almost everything related to a dataframe. We don't really care about perfo

by Fiahil 6y ago

At work, we use Parquet (https://parquet.apache.org/ https://parquet.apache.org/) for almost everything related to a dataframe. We don't really care about performance gains (although, it's nice to have), but we really like to have a schema. Note, we use mostly Python, some R, and a various range of ML or Optimisation tools, depending on the project.

jeremyjh 6y ago
Does Parquet provide a way to define foreign keys between different tables in a single dataset?
- xyzzy_plugh 6y ago
  Parquet files don't reference anything outside of the file, usually. A group of parquet files in a folder is usually considered a table, where the schema is union of the schema of the files.
xyzzy_plugh 6y ago
Parquet is kind of a royal pain in the ass compared to CSV/JSON/plaintext mostly because it uses a ton of Thrift encodings, resulting in mostly terrible/broken implementations anywhere outside of the Java/JVM ecosystem. If you're running Apache <Whatever> then sure, it'll probably be fine, but I'd recommend avoiding it if you start having to go down the rabbit hole of implementing support for things in your language du jour.
- Fiahil 6y ago
  The Rust and python impl are fine. But I get it, Parquet may not be perfect or optimal or whatever. It works as a simple, typed, columnar format. We had to pick a single file format recommendation for sending 100GB+ tables on FTP servers or dropbox, scanning terabytes of useless stuff only to grap an key-value pair, and properly reading integer and UTF-8 columns. Turns out, Parquet is practical. Enough for users to start using it instead of CSV. It could be Avro, but it's just not as easy.
  - xyzzy_plugh 6y ago
    > But I get it, Parquet may not be perfect or optimal or whatever. I actually think Parquet is pretty great in practice, I just have some issues with the sheer volume of abstractions necessary to implement it. I just wish it was anything other than Thrift. I would probably choose Parquet over anything else, though.
The_rationalist 6y ago
For exhaustivity sake, apache arrow could also do the work but Parquet seems more appropriate here https://stackoverflow.com/questions/56472727/difference-between-apache-parquet-and-arrow https://stackoverflow.com/questions/56472727/difference-betw...

by Fiahil 6y ago

jeremyjh 6y ago

Does Parquet provide a way to define foreign keys between different tables in a single dataset?

xyzzy_plugh 6y ago
Parquet files don't reference anything outside of the file, usually. A group of parquet files in a folder is usually considered a table, where the schema is union of the schema of the files.

xyzzy_plugh 6y ago

Parquet is kind of a royal pain in the ass compared to CSV/JSON/plaintext mostly because it uses a ton of Thrift encodings, resulting in mostly terrible/broken implementations anywhere outside of the Java/JVM ecosystem. If you're running Apache <Whatever> then sure, it'll probably be fine, but I'd recommend avoiding it if you start having to go down the rabbit hole of implementing support for things in your language du jour.

Fiahil 6y ago
The Rust and python impl are fine. But I get it, Parquet may not be perfect or optimal or whatever. It works as a simple, typed, columnar format. We had to pick a single file format recommendation for sending 100GB+ tables on FTP servers or dropbox, scanning terabytes of useless stuff only to grap an key-value pair, and properly reading integer and UTF-8 columns. Turns out, Parquet is practical. Enough for users to start using it instead of CSV. It could be Avro, but it's just not as easy.
- xyzzy_plugh 6y ago
  > But I get it, Parquet may not be perfect or optimal or whatever. I actually think Parquet is pretty great in practice, I just have some issues with the sheer volume of abstractions necessary to implement it. I just wish it was anything other than Thrift. I would probably choose Parquet over anything else, though.

The_rationalist 6y ago

For exhaustivity sake, apache arrow could also do the work but Parquet seems more appropriate here https://stackoverflow.com/questions/56472727/difference-between-apache-parquet-and-arrow https://stackoverflow.com/questions/56472727/difference-betw...