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Description

This error indicates that an attempt was made to store a JSON value in a MySQL JSON column, but the value's size exceeded the allowed limit. It typically occurs during INSERT or UPDATE operations when working with large JSON documents.

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Error Message

The JSON value is too big to be stored in a JSON column.

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Known Causes

3 known causes

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JSON Data Exceeds Column Limit

The size of the JSON document being written surpasses the maximum storage capacity for a JSON data type in MySQL, which is implicitly limited to 1GB.

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Server Resource Constraints

During the processing of a large JSON value, the MySQL server or underlying system encountered memory or buffer limitations, preventing successful storage.

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Inefficient JSON Construction

The application is generating overly verbose or deeply nested JSON structures, leading to documents that become too large for practical database storage.

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Solutions

3 solutions available

1. Increase JSON Column Size Limit (if applicable) easy

Temporarily increase the maximum size of JSON documents if the data is only slightly over the limit.

1

Check the current `max_allowed_packet` setting. This is the primary server-side limit for individual packet sizes, including JSON documents.

SHOW VARIABLES LIKE 'max_allowed_packet';

2

If the `max_allowed_packet` is too low, increase it. This can be done dynamically for the current session or permanently in the MySQL configuration file.

-- For current session (resets on server restart):
SET GLOBAL max_allowed_packet = 67108864; -- Set to 64MB (adjust as needed)

-- For permanent change, edit my.cnf or my.ini:
-- [mysqld]
-- max_allowed_packet = 67108864

3

After changing `max_allowed_packet` permanently, restart the MySQL server for the changes to take effect.

sudo systemctl restart mysql  # Or your specific restart command

2. Optimize JSON Data Structure medium

Reduce the size of your JSON documents by restructuring them or removing redundant data.

1

Analyze the JSON data that is causing the error. Identify large arrays, deeply nested objects, or repetitive data.

SELECT your_json_column FROM your_table WHERE JSON_LENGTH(your_json_column) > <some_threshold>;
-- Also, consider using tools to pretty-print and analyze the JSON structure externally.

2

Refactor the JSON to remove unnecessary fields, compress arrays (e.g., by using unique identifiers instead of full objects), or flatten nested structures where appropriate.

N/A (This is a data modeling/application logic task)

3

If possible, consider if a relational approach is more suitable for parts of the data that are growing excessively large within the JSON.

N/A

3. Store Large JSON in a Separate Table or BLOB/TEXT Column medium

Move excessively large JSON data to a different storage mechanism to avoid hitting JSON column limits.

1

Create a new table to store the large JSON documents, or add a `LONGTEXT` or `BLOB` column to the existing table.

CREATE TABLE large_json_data (
  id INT AUTO_INCREMENT PRIMARY KEY,
  parent_id INT,
  large_json LONGTEXT,
  FOREIGN KEY (parent_id) REFERENCES your_table(id)
);

-- OR, add to existing table:
ALTER TABLE your_table ADD COLUMN large_json LONGTEXT;

2

Modify your application logic to store the large JSON documents in this new column or table.

N/A (Application code modification)

3

If using a separate table, update your queries to join with `large_json_data` when you need to access the large JSON content.

SELECT t.*, lj.large_json FROM your_table t JOIN large_json_data lj ON t.id = lj.parent_id WHERE ...

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Related Errors

5 related errors

MySQL Error 3150: JSON Value Too Large