Snowflake: Load Big JSON File into Table – A Step-by-Step Guide

Snowflake, the cloud-based data warehousing platform, has revolutionized the way we work with big data. One of its most powerful features is the ability to load massive JSON files into tables, making it a breeze to work with complex data structures. In this article, we’ll take you through a step-by-step process on how to load a big JSON file into a Snowflake table.

Before We Begin

Before we dive into the tutorial, make sure you have the following prerequisites:

• A Snowflake account with a working environment
• A JSON file larger than 1MB (we’ll use a 5MB file for this example)
• Snowflake SQL client or a tool like Snowsight or DataGrip

Step 1: Create a Snowflake Stage

A Snowflake stage is a temporary storage area where you can load data files before loading them into tables. Create a new stage using the following command:

CREATE STAGE my_stage;

Replace “my_stage” with the desired name for your stage.

Step 2: Load the JSON File into the Stage

Using the Snowflake SQL client or your preferred tool, execute the following command to load the JSON file into the stage:

PUT file://path/to/your/jsonfile.json @"my_stage";

Replace “path/to/your/jsonfile.json” with the actual path to your JSON file. Make sure to use the correct file protocol (file://) and include the stage name at the end.

File Size Limitations

Snowflake has a file size limitation for loading data into a stage. If your JSON file is larger than 50MB, you’ll need to split it into smaller chunks. You can use tools like split or gsplit to divide the file into smaller parts.

Step 3: Create a Snowflake Table

Before loading the JSON data, you need to create a table to store it. Define the table schema according to your JSON file’s structure. For this example, let’s assume our JSON file has the following structure:

{
  "id": 1,
  "name": "John Doe",
  "address": {
    "street": "123 Main St",
    "city": "Anytown",
    "state": "CA",
    "zip": "12345"
  }
}

Create a table with the following command:

CREATE TABLE my_table (
  id INT,
  name VARCHAR(50),
  address VARIANT
);

Replace “my_table” with the desired name for your table. The VARIANT data type is used to store the nested JSON object.

Step 4: Load the JSON Data into the Table

Now it’s time to load the JSON data into the table. Use the COPY INTO command to load the data:

COPY INTO my_table (id, name, address)
FROM '@my_stage/jsonfile.json'
FILE_FORMAT = (TYPE = JSON);

Replace “my_table” with the actual name of your table, and “my_stage” with the name of your stage. The FILE_FORMAT option specifies that the file is in JSON format.

Step 5: Verify the Data

Once the data is loaded, verify that it has been successfully inserted into the table:

SELECT * FROM my_table;

This should return the data from the JSON file, including the nested object.

Nested JSON Objects

When working with nested JSON objects, Snowflake stores them as VARIANT data types. To access the nested object, use the parse_json() function:

SELECT id, name, parse_json(address) AS address
FROM my_table;

This will extract the nested object and display it as a separate column.

Optimizing Performance

When loading large JSON files, performance can be a concern. Here are some tips to optimize your loading process:

1. Use a Snowflake stage with multiple underlying storage locations to increase throughput.
2. Split large JSON files into smaller chunks to reduce loading time.
3. Use the PIPE command to load data in parallel, taking advantage of Snowflake’s multi-threading capabilities.
4. Consider using a Snowflake partner like Fivetran or Matillion to automate and optimize your data loading process.

Conclusion

Loading big JSON files into Snowflake tables is a straightforward process. By following these steps and considering performance optimization tips, you can easily work with massive JSON datasets in Snowflake. Remember to adapt the instructions to your specific use case and JSON file structure.

Keyword	Description
Snowflake	Cloud-based data warehousing platform
JSON	JavaScript Object Notation, a data interchange format
Stage	Temporary storage area in Snowflake for loading data files
COPY INTO	Snowflake command to load data into a table from a stage
VARIANT	Snowflake data type for storing nested JSON objects

By mastering the art of loading big JSON files into Snowflake tables, you’ll unlock the full potential of your data and take your analytics to the next level.

Frequently Asked Questions

Need help loading a massive JSON file into a Snowflake table? We’ve got you covered! Check out our top 5 FAQs below.