Summary of Data Unloading Features

This topic provides a quick-reference of the supported features for using the COPY INTO location command to bulk unload data from Snowflake tables into flat files. Some of the supported features are dictated by whether you are unloading to a Snowflake internal location or to an external location (e.g. AWS S3).

In this Topic:

Unloaded Data File Details

Feature Supported Type Notes
Location of files Local files Files are first unloaded to a Snowflake internal location, then can be downloaded locally using PUT.
Files in AWS S3 Files can be unloaded directly to any user-supplied bucket in Amazon S3, then can be downloaded locally using AWS utilities.
File formats Delimited (CSV, TSV, etc.) Any single-character delimiter is supported; default is comma (i.e. CSV).
JSON  
File encoding UTF-8 Unloaded files are encoded using UTF-8.

Compression of Unloaded Data Files

Location Supported Type Notes
Files unloaded to Snowflake internal location or AWS S3 gzip By default, all unloaded data files are compressed using gzip, unless compression is explicitly disabled or a different method is specified.
bzip2 Unloaded data files can be compressed using bzip2, Brotli, or ZStandard; note that this is currently a preview feature.
Brotli
Zstandard

Encryption of Unloaded Data Files

Location Supported Type Notes
Files unloaded to Snowflake internal location 128-bit or 256-bit keys All data files unloaded to Snowflake internal locations are automatically encrypted using 128-bit keys. The files are then unencrypted when they are downloaded to the local directory. 256-bit keys can be enabled (for stronger encryption); however, additional configuration is required.
Files unloaded to AWS S3 Encryption by user-supplied key Data files unloaded to S3 can be encrypted if a security key (for encrypting the files) is provided to Snowflake.