nodeLimit.h File Reference

#include "nodes/execnodes.h"

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Functions
LimitState *	ExecInitLimit (Limit *node, EState *estate, int eflags)
void	ExecEndLimit (LimitState *node)
void	ExecReScanLimit (LimitState *node)

Function Documentation

ExecEndLimit()

void ExecEndLimit

(

LimitState *

node

)

Definition at line 535 of file nodeLimit.c.

{
    ExecFreeExprContext(&node->ps);
    ExecEndNode(outerPlanState(node));
}

References ExecEndNode(), ExecFreeExprContext(), outerPlanState, and LimitState::ps.

Referenced by ExecEndNode().

ExecInitLimit()

LimitState* ExecInitLimit	(	Limit *	node,
		EState *	estate,
		int	eflags
	)

Definition at line 448 of file nodeLimit.c.

{
    LimitState *limitstate;
    Plan       *outerPlan;
 
    /* check for unsupported flags */
    Assert(!(eflags & EXEC_FLAG_MARK));
 
    /*
     * create state structure
     */
    limitstate = makeNode(LimitState);
    limitstate->ps.plan = (Plan *) node;
    limitstate->ps.state = estate;
    limitstate->ps.ExecProcNode = ExecLimit;
 
    limitstate->lstate = LIMIT_INITIAL;
 
    /*
     * Miscellaneous initialization
     *
     * Limit nodes never call ExecQual or ExecProject, but they need an
     * exprcontext anyway to evaluate the limit/offset parameters in.
     */
    ExecAssignExprContext(estate, &limitstate->ps);
 
    /*
     * initialize outer plan
     */
    outerPlan = outerPlan(node);
    outerPlanState(limitstate) = ExecInitNode(outerPlan, estate, eflags);
 
    /*
     * initialize child expressions
     */
    limitstate->limitOffset = ExecInitExpr((Expr *) node->limitOffset,
                                           (PlanState *) limitstate);
    limitstate->limitCount = ExecInitExpr((Expr *) node->limitCount,
                                          (PlanState *) limitstate);
    limitstate->limitOption = node->limitOption;
 
    /*
     * Initialize result type.
     */
    ExecInitResultTypeTL(&limitstate->ps);
 
    limitstate->ps.resultopsset = true;
    limitstate->ps.resultops = ExecGetResultSlotOps(outerPlanState(limitstate),
                                                    &limitstate->ps.resultopsfixed);
 
    /*
     * limit nodes do no projections, so initialize projection info for this
     * node appropriately
     */
    limitstate->ps.ps_ProjInfo = NULL;
 
    /*
     * Initialize the equality evaluation, to detect ties.
     */
    if (node->limitOption == LIMIT_OPTION_WITH_TIES)
    {
        TupleDesc   desc;
        const TupleTableSlotOps *ops;
 
        desc = ExecGetResultType(outerPlanState(limitstate));
        ops = ExecGetResultSlotOps(outerPlanState(limitstate), NULL);
 
        limitstate->last_slot = ExecInitExtraTupleSlot(estate, desc, ops);
        limitstate->eqfunction = execTuplesMatchPrepare(desc,
                                                        node->uniqNumCols,
                                                        node->uniqColIdx,
                                                        node->uniqOperators,
                                                        node->uniqCollations,
                                                        &limitstate->ps);
    }
 
    return limitstate;
}

References Assert(), LimitState::eqfunction, EXEC_FLAG_MARK, ExecAssignExprContext(), ExecGetResultSlotOps(), ExecGetResultType(), ExecInitExpr(), ExecInitExtraTupleSlot(), ExecInitNode(), ExecInitResultTypeTL(), ExecLimit(), PlanState::ExecProcNode, execTuplesMatchPrepare(), LimitState::last_slot, LIMIT_INITIAL, LIMIT_OPTION_WITH_TIES, LimitState::limitCount, Limit::limitCount, LimitState::limitOffset, Limit::limitOffset, LimitState::limitOption, Limit::limitOption, LimitState::lstate, makeNode, outerPlan, outerPlanState, PlanState::plan, LimitState::ps, PlanState::ps_ProjInfo, PlanState::resultops, PlanState::resultopsfixed, PlanState::resultopsset, PlanState::state, and Limit::uniqNumCols.

Referenced by ExecInitNode().

ExecReScanLimit()

void ExecReScanLimit

(

LimitState *

node

)

Definition at line 543 of file nodeLimit.c.

{
    PlanState  *outerPlan = outerPlanState(node);
 
    /*
     * Recompute limit/offset in case parameters changed, and reset the state
     * machine.  We must do this before rescanning our child node, in case
     * it's a Sort that we are passing the parameters down to.
     */
    recompute_limits(node);
 
    /*
     * if chgParam of subnode is not null then plan will be re-scanned by
     * first ExecProcNode.
     */
    if (outerPlan->chgParam == NULL)
        ExecReScan(outerPlan);
}

References ExecReScan(), outerPlan, outerPlanState, and recompute_limits().

Referenced by ExecReScan().