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.

Note that some of the supported features, particularly compression and encryption, are dictated by whether you are unloading to a Snowflake internal location or an external location (i.e. AWS S3 or Microsoft Azure).

In this Topic:

Unloaded Data File Details

Feature Supported 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.
Files in Microsoft Azure Files can be unloaded directly to any user-supplied container in Microsoft Azure, then can be downloaded locally using Azure utilities.
File formats CSV and any other delimited formats (e.g. TSV) Any single-character delimiter is supported; default is comma (i.e. CSV).
JSON  
Parquet  
File encoding UTF-8 Unloaded files are encoded using UTF-8.

Compression of Unloaded Data Files

Location of Files Supported Notes
Interal or external location gzip By default, all unloaded data files are compressed using gzip, unless compression is explicitly disabled or one of the other supported compression methods is explicitly specified.
bzip2
Brotli Note that support for Brotli and ZStandard compression of unloaded files is currently a preview feature.
Zstandard

Encryption of Unloaded Data Files

Location of Files Supported Notes
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 unencrypted when they are downloaded to the local directory.

256-bit keys can be enabled (for stronger encryption); however, additional configuration is required.

External location User-supplied key Data files unloaded to S3 or Azure can be encrypted if a security key (for encrypting the files) is provided to Snowflake.