Function ExecInitHashJoin

src/backend/executor/nodeHashjoin.c:799–1023

---------------------------------------------------------------- * ExecInitHashJoin * * Init routine for HashJoin node. * ---------------------------------------------------------------- */

 * ----------------------------------------------------------------
 */
HashJoinState *
ExecInitHashJoin(HashJoin *node, EState *estate, int eflags)
{
	HashJoinState *hjstate;
	PlanState  *outerState;
	HashState  *hstate;
	Plan	   *outerNode;
	Hash	   *hashNode;
	TupleDesc	outerDesc,
				innerDesc;
	const TupleTableSlotOps *ops;

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

	/*
	 * create state structure
	 */
	hjstate = makeNode(HashJoinState);
	hjstate->js.ps.plan = (Plan *) node;
	hjstate->js.ps.state = estate;
	hjstate->reuse_hashtable = (eflags & EXEC_FLAG_REWIND) != 0;

	/*
	 * If eflag contains EXEC_FLAG_REWIND,
	 * then this node is not eager free safe.
	 */
	hjstate->delayEagerFree = (eflags & EXEC_FLAG_REWIND) != 0;
	/*
	 * See ExecHashJoinInitializeDSM() and ExecHashJoinInitializeWorker()
	 * where this function may be replaced with a parallel version, if we
	 * managed to launch a parallel query.
	 */
	if (node->join.plan.parallel_aware)
	{
		hjstate->js.ps.ExecProcNode = ExecParallelHashJoin;
	}
	else
	{
		hjstate->js.ps.ExecProcNode = ExecHashJoin;
	}
	hjstate->js.jointype = node->join.jointype;

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

	if (node->hashqualclauses != NIL)
	{
		/* CDB: This must be an IS NOT DISTINCT join!  */
		Assert(isNotDistinctJoin(node->hashqualclauses));
		hjstate->hj_nonequijoin = true;
	}
	else
		hjstate->hj_nonequijoin = false;