Function ExecInitHash

src/backend/executor/nodeHash.c:456–503

---------------------------------------------------------------- * ExecInitHash * * Init routine for Hash node * ---------------------------------------------------------------- */

 * ----------------------------------------------------------------
 */
HashState *
ExecInitHash(Hash *node, EState *estate, int eflags)
{
	HashState  *hashstate;

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

	/*
	 * create state structure
	 */
	hashstate = makeNode(HashState);
	hashstate->ps.plan = (Plan *) node;
	hashstate->ps.state = estate;
	hashstate->ps.ExecProcNode = ExecHash;
	hashstate->hashtable = NULL;
	hashstate->hashkeys = NIL;	/* will be set by parent HashJoin */

	hashstate->rfstate = NULL;

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

	/*
	 * initialize child nodes
	 */
	outerPlanState(hashstate) = ExecInitNode(outerPlan(node), estate, eflags);

	/*
	 * initialize our result slot and type. No need to build projection
	 * because this node doesn't do projections.
	 */
	ExecInitResultTupleSlotTL(&hashstate->ps, &TTSOpsMinimalTuple);
	hashstate->ps.ps_ProjInfo = NULL;

	/*
	 * initialize child expressions
	 */
	Assert(node->plan.qual == NIL);
	hashstate->hashkeys =
		ExecInitExprList(node->hashkeys, (PlanState *) hashstate);

	return hashstate;
}

/* ---------------------------------------------------------------
 *		ExecEndHash