PostgreSQL: implementing Indexing on JSONB Fields for Nested Queries Performance
I've hit a wall trying to I'm upgrading from an older version and I've been struggling with this for a few days now and could really use some help... I'm experiencing performance optimization when querying a PostgreSQL database that utilizes JSONB fields extensively. Specifically, I have a table called `orders` where one of the columns, `order_data`, contains JSONB data. An example of what this data looks like is: ```json { "customer_id": 123, "items": [ { "product_id": 456, "quantity": 2 }, { "product_id": 789, "quantity": 1 } ], "status": "shipped" } ``` My goal is to retrieve all orders for a specific customer and filter based on the `status` field. I initially tried the following query: ```sql SELECT * FROM orders WHERE order_data->>'customer_id' = '123' AND order_data->>'status' = 'shipped'; ``` While this query works, it is incredibly slow, especially when dealing with a large dataset (over a million rows). I read that indexing the JSONB fields can help, so I created a GIN index like this: ```sql CREATE INDEX idx_order_data ON orders USING gin (order_data); ``` However, the performance hasn't improved significantly. When I run `EXPLAIN ANALYZE` on the query, it shows that the index is not being used effectively: ``` Seq Scan on orders (cost=0.00..1000000.00 rows=1000000) (actual time=1200.123..1220.456 rows=1000 loops=1) ``` I also tried using a more specific index with expressions: ```sql CREATE INDEX idx_order_customer_status ON orders USING gin ((order_data->>'customer_id', order_data->>'status')); ``` Still, the performance improvement is negligible. What am I missing? Is there a more effective way to index and query JSONB fields for better performance? Any insights or best practices would be greatly appreciated! I'd be grateful for any help. The stack includes Sql and several other technologies. Cheers for any assistance! The project is a web app built with Sql. What am I doing wrong?