Function ExecInitDynamicIndexScan

src/backend/executor/nodeDynamicIndexscan.c:39–99

* Initialize ScanState in DynamicIndexScan. */

 * Initialize ScanState in DynamicIndexScan.
 */
DynamicIndexScanState *
ExecInitDynamicIndexScan(DynamicIndexScan *node, EState *estate, int eflags)
{
	DynamicIndexScanState *dynamicIndexScanState;
	ListCell   *lc;
	int			i;

	/* check for unsupported flags */
	Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));

	dynamicIndexScanState = makeNode(DynamicIndexScanState);
	dynamicIndexScanState->ss.ps.plan = (Plan *) node;
	dynamicIndexScanState->ss.ps.state = estate;
	dynamicIndexScanState->ss.ps.ExecProcNode = ExecDynamicIndexScan;
	dynamicIndexScanState->eflags = eflags;

	dynamicIndexScanState->scan_state = SCAN_INIT;
	dynamicIndexScanState->whichPart = -1;
	dynamicIndexScanState->nOids = list_length(node->partOids);
	dynamicIndexScanState->partOids = palloc(sizeof(Oid) * dynamicIndexScanState->nOids);
	foreach_with_count(lc, node->partOids, i)
		dynamicIndexScanState->partOids[i] = lfirst_oid(lc);

	/*
	 * Initialize child expressions
	 *
	 * These are not used for anything, we rely on the child IndexScan node to
	 * do all evaluation for us. But I think this is still needed to find and
	 * process any SubPlans. See comment in ExecInitIndexScan.
	 */
	dynamicIndexScanState->ss.ps.qual = ExecInitQual(node->indexscan.scan.plan.qual,
													 (PlanState *) dynamicIndexScanState);

	/*
	 * tuple table initialization
	 */
	Relation	scanRel = ExecOpenScanRelation(estate, node->indexscan.scan.scanrelid, eflags);

	ExecInitScanTupleSlot(estate, &dynamicIndexScanState->ss, RelationGetDescr(scanRel), table_slot_callbacks(scanRel));

	/* Dynamic table/index/bitmap scan can't tell the ops of tupleslot */
	dynamicIndexScanState->ss.ps.scanopsfixed = false;
	dynamicIndexScanState->ss.ps.scanopsset = true;

	/*
	 * Initialize result tuple type and projection info.
	 */
	ExecInitResultTypeTL(&dynamicIndexScanState->ss.ps);

	/*
	 * This context will be reset per-partition to free up per-partition copy
	 * of LogicalIndexInfo
	 */
	dynamicIndexScanState->partitionMemoryContext = AllocSetContextCreate(CurrentMemoryContext,
																		  "DynamicIndexScanPerPartition",
																		  ALLOCSET_DEFAULT_MINSIZE,
																		  ALLOCSET_DEFAULT_INITSIZE,
																		  ALLOCSET_DEFAULT_MAXSIZE);