ProjectSet

Description

Evaluates set-returning expressions in the target list for rows from its child.

Core node tag

T_ProjectSet

Structured EXPLAIN Node Type

ProjectSet

Inputs

One child plan

Output

Expanded result tuples

Executor initializer

ExecInitProjectSet

Memory mechanism

unclassified

EXPLAIN names and attributes

Structured formats use the Node Type above. Text-format spellings can also include operation, strategy, join type, scan direction or aggregation-stage attributes.

Text names recorded by this source: ProjectSet.

Parallel-aware and parallel-safe are different plan properties. A node running inside a parallel worker is not necessarily a parallel-aware node.

Memory and temporary storage

This extraction does not assign a universal memory limit or spill policy to this node. Inspect the same-build implementation and its expressions or provider.

Parallel execution and instrumentation

The source callbacks below can coordinate execution or collect worker instrumentation. Their presence is not a blanket claim that this node supports a shared parallel scan or shared state.

Callbacks in this build: none extracted from this node implementation.

Executor implementation notes

nodeProjectSet.c support for evaluating targetlists containing set-returning functions

ProjectSet nodes are inserted by the planner to evaluate set-returning functions in the targetlist. It's guaranteed that all set-returning functions are directly at the top level of the targetlist, i.e. they can't be inside more-complex expressions. If that'd otherwise be the case, the planner adds additional ProjectSet nodes.

Return tuples after evaluating the targetlist (which contains set returning functions).

Reset per-tuple context to free expression-evaluation storage allocated for a potentially previously returned tuple. Note that the SRF argument context has a different lifetime and is reset below.

Check to see if we're still projecting out tuples from a previous scan tuple (because there is a function-returning-set in the projection expressions). If so, try to project another one.

EXPLAIN identity in core source

case T_ProjectSet:
			pname = sname = "ProjectSet";
			break;

Related entries

• EXPLAIN
• Using EXPLAIN
• Parallel plans

Documentation and source

• src/backend/commands/explain.c:1382
• src/backend/executor/execProcnode.c:171
• src/backend/executor/nodeProjectSet.c
• src/include/nodes/plannodes.h

Compare versions

PostgreSQL 17 → 18: unchanged.

Compares recorded interfaces and attributes. Source fingerprints and build metadata are excluded; an absent sample is not proof of the introduction or removal release.

Related entries

• LimitLimit
• LockRowsLockRows
• ResultResult