Tid Range Scan

Description

Scans a relation over a range of tuple identifiers.

Core node tag

T_TidRangeScan

Structured EXPLAIN Node Type

Tid Range Scan

Inputs

A relation and tuple-identifier bounds

Output

Selected table tuples

Executor initializer

ExecInitTidRangeScan

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: Tid Range Scan.

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

nodeTidrangescan.c Routines to support TID range scans of relations

It's sufficient to check varattno to identify the CTID variable, as any Var in the relation scan qual must be for our table. (Even if it's a parameterized scan referencing some other table's CTID, the other table's Var would have become a Param by the time it gets here.)

For the given 'expr', build and return an appropriate TidOpExpr taking into account the expr's operator and operand order.

Extract the qual subexpressions that yield TIDs to search for, and compile them into ExprStates if they're ordinary expressions.

Compute and set node's block and offset range to scan by evaluating node->trss_tidexprs. Returns false if we detect the range cannot contain any tuples. Returns true if it's possible for the range to contain tuples. We don't bother validating that trss_mintid is less than or equal to trss_maxtid, as the scan_set_tidrange() table AM function will handle that.

EXPLAIN identity in core source

case T_TidRangeScan:
			pname = sname = "Tid Range Scan";
			break;

Related entries

• EXPLAIN
• Using EXPLAIN
• Parallel plans
• enable_tidscan

Documentation and source

• src/backend/commands/explain.c:1459
• src/backend/executor/execProcnode.c:244
• src/backend/executor/nodeTidrangescan.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

• Bitmap Heap ScanBitmapHeapScan
• CTE ScanCteScan
• Function ScanFunctionScan
• Index Only ScanIndexOnlyScan
• Index ScanIndexScan
• Named Tuplestore ScanNamedTuplestoreScan
• Sample ScanSampleScan
• Seq ScanSeqScan
• Subquery ScanSubqueryScan
• Table Function ScanTableFuncScan
• Tid ScanTidScan
• Values ScanValuesScan