![[str_idx_gin.png|256]] - **Description**: "Generalized Inverted Index". Map "keys" (like words in a document or elements in an array) to the list of "postings" (rows) where they appear. - **Supported Operators**: `<@`, `@>`, `=`, `&&`. - **Special Features**: - Multiple entries per row. - Slower to update than B-Tree but much faster for searching "contained" values. - **Metaphor**: The index at the back of a massive technical textbook. Instead of reading the whole book for "Postgres", you go to the P's and it gives you a list of every page number where it appears.