# The Grand Operations When PostgreSQL receives a query, the planner constructs a tree of plan nodes. Subplans and initialization plans can add cross-references that make the complete structure feel graph-like, but `EXPLAIN` presents a rooted plan tree whose parent nodes consume rows from their children. These are the verbs of our database. Some operations read data, some join streams, and others sort, aggregate, or reshape results. The cards below are a lookup reference: begin with the compact workflow in Chapter 4, then open a card when a real plan contains an unfamiliar node. --- ## ![[Operations/Table/_Table]] --- ## ![[Operations/Index/_Index]] --- ## ![[Operations/Page/_Page]] --- ## ![[Operations/ResultSet/_ResultSet]] --- ## ![[Operations/Distributed/_Distributed]] --- ## ![[Operations/Tuple/_Tuple]] --- ## ![[Operations/Other/_Other]]