# PostgreSQL JSONB Indexing
Today I learned how to significantly improve query performance on JSON data in PostgreSQL using GIN (Generalized Inverted Index) indexes.
## The Challenge with JSON Data
When storing JSON data in PostgreSQL using the JSONB type, queries that filter or search within the JSON structure can become slow as the dataset grows. This is because without proper indexing, PostgreSQL needs to scan each row and parse the JSON structure.
## GIN Indexes to the Rescue
GIN indexes are perfect for JSONB columns because they index each key and value within the JSON structure, making queries that use operators like @>, ?, ?& much faster.
## Performance Improvement
In our production database, adding a GIN index to a JSONB column reduced query time from 2.3 seconds to just 0.05 seconds for a table with over 1 million rows.
## Considerations
While GIN indexes greatly improve query performance, they do increase the database size and slow down write operations slightly. It's important to balance these trade-offs based on your specific read/write patterns.
Code Example
-- Create a GIN index on a JSONB column
CREATE INDEX idx_data ON table_name USING GIN (data_column);
-- Query using the index
SELECT * FROM table_name WHERE data_column @> '{"key": "value"}'::jsonb;PostgreSQLDatabasePerformance