topic Re: Write in Single CSV file in Data Engineering

Write in Single CSV file

Mohit_Kumar_Sut — Mon, 03 Oct 2022 16:54:59 GMT

We are reading 520GB partitions files from CSV and when we write in a Single CSV using repartition(1) it is taking 25+ hours. please let us know an optimized way to create a single CSV file so that our process could complete within 5 hours.

Re: Write in Single CSV file

Hubert-Dudek — Mon, 03 Oct 2022 20:01:59 GMT

If you repartition(1), only one core of your whole cluster works. Please use repartition to the number of cores (SparkContext.DefaultParallelism).

After writing, you will get one file per core, so please use other software to merge files if you want to have only one (ADF has some excellent options for that in copy).

Re: Write in Single CSV file

Mohit_Kumar_Sut — Thu, 06 Oct 2022 05:50:44 GMT

Thank you for your time and support, is there any other effective method to combine part CSV files into a single CSV file in databricks?

Re: Write in Single CSV file

Hubert-Dudek — Fri, 14 Oct 2022 11:32:53 GMT

The method in databricks is one that you are using and is slow (repartition(1)).

Re: Write in Single CSV file

jose_gonzalez — Fri, 28 Oct 2022 22:57:58 GMT

You can use coalesce(1) for example:

df.coalesce(1).write.option("header","true").csv("path_to_save_your_CSV")

Re: Write in Single CSV file

Anonymous — Sat, 12 Nov 2022 06:51:02 GMT

Hi @mohit kumar suthar

Hope all is well! Just wanted to check in if you were able to resolve your issue and would you be happy to share the solution or mark an answer as best? Else please let us know if you need more help.

We'd love to hear from you.

Thanks!