PostgreSQL: Unexpected Performance Issues with JSONB Column Indexing
I'm facing a significant performance issue when querying a PostgreSQL database that utilizes a `JSONB` column. The table `events` has around 1 million records, and the structure is as follows: ```sql CREATE TABLE events ( id SERIAL PRIMARY KEY, event_data JSONB, created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ); ``` I've created a GIN index on the `event_data` column to optimize querying. Here's the index creation statement: ```sql CREATE INDEX idx_event_data ON events USING GIN (event_data); ``` When I run the following query to retrieve records based on a specific key in the JSONB object, the performance is shockingly slow: ```sql SELECT * FROM events WHERE event_data ->> 'type' = 'notification'; ``` I expected this query to be efficient due to the GIN index, but it takes anywhere from 2 to 5 seconds to return results. Additionally, I've tried analyzing the table with `ANALYZE events;`, but it didn't improve the situation. I also checked that the statistics for the table are up to date, and they seem fine. Similarly, when I run the query with `EXPLAIN ANALYZE`, I see that it’s performing a sequential scan instead of using the index: ```plaintext Seq Scan on events (cost=0.00..123456.78 rows=1000 width=123) Filter: (event_data ->> 'type' = 'notification') ``` I am wondering if `JSONB` indexing has some limitations I am not aware of, or if there’s a specific configuration or query modification I should consider to enhance the performance. Is there a better way to structure my queries or perhaps a different indexing strategy that could help? Any insights would be appreciated!