Hash, GIN, and GiST Indexes

You've likely encountered B-Tree indexes, which are excellent for exact matches and range scans on single columns. But what about more complex data types or unique query patterns?

PostgreSQL offers specialized index types to supercharge these specific scenarios, allowing for efficient querying where B-Trees fall short.

A Hash Index stores a hash value for each indexed column. It's optimized for very fast equality queries (using the = operator).

• Think of it like a dictionary lookup: incredibly fast if you know the exact key.
• They can be faster than B-Trees for simple equality checks on very large tables, especially with many duplicates.