Postgres Indexing Basics: When a B-tree Isn't Enough

The default: B-tree

Postgres creates a B-tree index by default, and it's the right call for equality and range queries on scalar columns.

Arrays and JSON need GIN

A column like tags text[] benefits from a GIN index when you filter with @> or &&. A B-tree can't do that efficiently.

CREATE INDEX idx_articles_tags ON "Article" USING GIN (tags);

Rule of thumb

Match the index type to the operator you actually query with — EXPLAIN ANALYZE will tell you immediately if Postgres skipped your index.