Function ExecInitTidScan

src/backend/executor/nodeTidscan.c:499–560

---------------------------------------------------------------- * ExecInitTidScan * * Initializes the tid scan's state information, creates * scan keys, and opens the base and tid relations. * * Parameters: * node: TidScan node produced by the planner. * estate: the execution state initialized in InitPlan. * ---------------------------------------------------------------- */

 * ----------------------------------------------------------------
 */
TidScanState *
ExecInitTidScan(TidScan *node, EState *estate, int eflags)
{
	TidScanState *tidstate;
	Relation	currentRelation;

	/*
	 * create state structure
	 */
	tidstate = makeNode(TidScanState);
	tidstate->ss.ps.plan = (Plan *) node;
	tidstate->ss.ps.state = estate;
	tidstate->ss.ps.ExecProcNode = ExecTidScan;

	/*
	 * Miscellaneous initialization
	 *
	 * create expression context for node
	 */
	ExecAssignExprContext(estate, &tidstate->ss.ps);

	/*
	 * mark tid list as not computed yet
	 */
	tidstate->tss_TidList = NULL;
	tidstate->tss_NumTids = 0;
	tidstate->tss_TidPtr = -1;

	/*
	 * open the scan relation
	 */
	currentRelation = ExecOpenScanRelation(estate, node->scan.scanrelid, eflags);

	tidstate->ss.ss_currentRelation = currentRelation;
	tidstate->ss.ss_currentScanDesc = NULL; /* no heap scan here */

	/*
	 * get the scan type from the relation descriptor.
	 */
	ExecInitScanTupleSlot(estate, &tidstate->ss,
						  RelationGetDescr(currentRelation),
						  table_slot_callbacks(currentRelation));

	/*
	 * Initialize result type and projection.
	 */
	ExecInitResultTypeTL(&tidstate->ss.ps);
	ExecAssignScanProjectionInfo(&tidstate->ss);

	/*
	 * initialize child expressions
	 */
	tidstate->ss.ps.qual =
		ExecInitQual(node->scan.plan.qual, (PlanState *) tidstate);

	TidExprListCreate(tidstate);

	/*