Export table from Bigquery into GCS split sizes

0
votes

I am exporting a table of size>1GB from Bigquery into GCS but it splits the files into very small files of 2-3 MB. Is there a way to get bigger files like 40-60MB per files rather than 2-3 MB.

I do the expport via the api https://cloud.google.com/bigquery/docs/exporting-data#exporting_data_into_one_or_more_files

https://cloud.google.com/bigquery/docs/reference/v2/jobs

The source table size is 60 GB on Bigquery. I extract the data with format - NewLine_Delimited_Json and GZIP compression

destination_cloud_storage_uris=[
        'gs://bucket_name/main_folder/partition_date=xxxxxxx/part-*.gz'
    ]
2
google-bigquery
How are you doing this extract operation from the options in here(cloud.google.com/bigquery/docs/…)? If you just run the following command: "bq extract <your-dataset>.<your-table> gs://<bucket-destination>/<file_name>*.csv" it splits your table in 2-3 MB files? I've just tried and using that command it split my 2.4 GB table into 6 files. - VictorGGl
more details added in the question - Amit Kumar
As per your description it doesn't seem this is working as intended for you. If it is not the case that your table is a partitioned table then you shouldn't get this small files. So, Can you raise a private issue in this link: issuetracker.google.com/issues/new?component=187164 providing your Project Number (not Project ID) and as much information as possible describing your case? Feel free to attach the issue link here as a comment, and a final resolution as an answer to your own question - VictorGGl

2 Answers

2
votes

Are you trying to export partitioned table? If yes, each partition is exported as different table and it might cause small files. I run the export in cli with each of the following commands and received in both cases files of size 49 MB:

bq extract --compression=GZIP --destination_format=NEWLINE_DELIMITED_JSON project:dataset.table gs://bucket_name/path5-component/file-name-*.gz

bq extract --compression=GZIP project:dataset.table gs://bucket_name/path5-component/file-name-*.gz
1
votes

Please add more details to the question so we can provide specific advice: How are you exactly asking for this export?

Nevertheless, if you have many files in GCS and you want to merge them all into one, you can do:

gsutil compose gs://bucket/obj1 [gs://bucket/obj2 ...] gs://bucket/composite