Function ExecInitSequence

src/backend/executor/nodeSequence.c:26–76

#include "miscadmin.h"

SequenceState *
ExecInitSequence(Sequence *node, EState *estate, int eflags)
{
	SequenceState *sequenceState;
	PlanState  *lastPlanState;

	/* Check for unsupported flags */
	Assert(!(eflags & EXEC_FLAG_MARK));

	/* Sequence should not contain 'qual'. */
	Assert(node->plan.qual == NIL);

	sequenceState = makeNode(SequenceState);
	sequenceState->ps.plan = (Plan *)node;
	sequenceState->ps.state = estate;
	sequenceState->ps.ExecProcNode = ExecSequence;

	int numSubplans = list_length(node->subplans);
	Assert(numSubplans >= 1);
	sequenceState->subplans = (PlanState **)palloc0(numSubplans * sizeof(PlanState *));
	sequenceState->numSubplans = numSubplans;
	
	/* Initialize subplans */
	ListCell *lc;
	int no = 0;
	foreach (lc, node->subplans)
	{
		Plan *subplan = (Plan *)lfirst(lc);
		Assert(subplan != NULL);
		Assert(no < numSubplans);
		
		sequenceState->subplans[no] = ExecInitNode(subplan, estate, eflags);
		no++;
	}

	sequenceState->initState = true;
	
	/* Sequence does not need projection. */
	sequenceState->ps.ps_ProjInfo = NULL;

	/*
	 * Initialize result type. We will pass through the last child slot.
	 */
	lastPlanState = sequenceState->subplans[numSubplans - 1];
	ExecInitResultTypeTL(&sequenceState->ps);
	sequenceState->ps.resultopsset = true;
	sequenceState->ps.resultops = ExecGetResultSlotOps(lastPlanState,
													   &lastPlanState->resultopsfixed);

	return sequenceState;
}

/*
 * completeSubplan