PostgreSQLmedium

What is a GIN index and when would you use it?

Tags

#gin#index#jsonb#arrays

Back to category Practice quiz

Answer

GIN (Generalized Inverted Index) is great for “contains” queries on composite types like arrays and `jsonb` (e.g., `@>`, `?`). It indexes many-to-many relationships between keys and rows.

CREATE INDEX idx_events_payload ON events USING GIN (payload);

-- example query (jsonb contains)
SELECT * FROM events WHERE payload @> '{"type":"click"}';

Related questions

GIN vs GiST indexes: when would you use each?

#postgres#indexes#gin

What is a partial index in PostgreSQL and when is it useful?

#postgres#index#partial-index

What is an index-only scan and what is the “visibility map” role?

#index-only-scan#visibility-map#index

BRIN vs B-tree index — when is BRIN a good fit?

#brin#btree#index

JSON vs JSONB in Postgres — what’s the difference (and why JSONB is common)?

#json#jsonb#gin

What is an index in PostgreSQL and how does it help performance?

#index#btree#performance