MySQL 5.7 - implementing Handling JSON Data and Indexing for Performance
I've looked through the documentation and I'm still confused about I've been banging my head against this for hours... After trying multiple solutions online, I still can't figure this out. I'm trying to optimize a query that involves filtering large JSON columns in MySQL 5.7. I have a table named `user_data` that stores user profiles, and one of the columns, `preferences`, is of type JSON. The structure of the JSON is somewhat complex, and I'm working with performance optimization when querying specific keys within that JSON. For example, I have the following query that retrieves users based on their preferences: ```sql SELECT * FROM user_data WHERE JSON_UNQUOTE(JSON_EXTRACT(preferences, '$.notifications.email')) = 'true'; ``` This query runs fine for a small dataset, but as the number of records increases, it's becoming significantly slower. I've tried adding an index on the `preferences` column like this: ```sql ALTER TABLE user_data ADD INDEX idx_email_notifications ((JSON_UNQUOTE(JSON_EXTRACT(preferences, '$.notifications.email')))); ``` However, I receive an behavior saying "Function-based indexes are not supported in this version of MySQL". I've also considered using a generated column for the email notification preference: ```sql ALTER TABLE user_data ADD COLUMN email_notifications VARCHAR(5) AS (JSON_UNQUOTE(JSON_EXTRACT(preferences, '$.notifications.email'))) STORED; ``` After adding the generated column, I created an index on it: ```sql CREATE INDEX idx_email_notifications ON user_data(email_notifications); ``` Now the query runs much faster, but I'm curious if there are any best practices I should follow when working with JSON data in MySQL 5.7. Are there specific considerations for indexing, or alternative approaches I might be missing? Also, is there a way to ensure that the generated columns remain updated without impacting performance? Any tips would be greatly appreciated! Any ideas what could be causing this? This is part of a larger API I'm building. Has anyone else encountered this? For reference, this is a production web app. I'm open to any suggestions.