EXPLAIN - Insights: Expensive

Description:

Postgres will often spend most of its time on a query in a small set of plan nodes. This insight identifies the most expensive nodes (according to estimated cost) to guide optimization. Even if other insights point to different nodes, you should probably focus on the most expensive ones first: there is little to be gained by optimizing an inefficiency unless it is also a bottleneck.

Recommended Action:

A node flagged as expensive should have other insights as well: prioritize addressing those over other issues in nodes that are not flagged as expensive.