Function ExecInitAgg

src/backend/executor/nodeAgg.c:3502–4327

----------------- * ExecInitAgg * * Creates the run-time information for the agg node produced by the * planner and initializes its outer subtree. * * ----------------- */

 * -----------------
 */
AggState *
ExecInitAgg(Agg *node, EState *estate, int eflags)
{
	AggState   *aggstate;
	AggStatePerAgg peraggs;
	AggStatePerTrans pertransstates;
	AggStatePerGroup *pergroups;
	Plan	   *outerPlan;
	ExprContext *econtext;
	TupleDesc	scanDesc;
	int			max_aggno;
	int			max_transno;
	int			numaggrefs;
	int			numaggs;
	int			numtrans;
	int			phase;
	int			phaseidx;
	ListCell   *l;
	Bitmapset  *all_grouped_cols = NULL;
	int			numGroupingSets = 1;
	int			numPhases;
	int			numHashes;
	int			i = 0;
	int			j = 0;
	bool		use_hashing = (node->aggstrategy == AGG_HASHED ||
							   node->aggstrategy == AGG_MIXED);
	int			numgsets = 0;

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

	/*
	 * create state structure
	 */
	aggstate = makeNode(AggState);
	aggstate->ss.ps.plan = (Plan *) node;
	aggstate->ss.ps.state = estate;
	aggstate->ss.ps.ExecProcNode = ExecAgg;

	aggstate->aggs = NIL;
	aggstate->numaggs = 0;
	aggstate->numtrans = 0;
	aggstate->aggstrategy = node->aggstrategy;
	aggstate->aggsplit = node->aggsplit;
	aggstate->maxsets = 0;
	aggstate->projected_set = -1;
	aggstate->current_set = 0;
	aggstate->peragg = NULL;
	aggstate->pertrans = NULL;
	aggstate->curperagg = NULL;
	aggstate->curpertrans = NULL;
	aggstate->input_done = false;
	aggstate->agg_done = false;
	aggstate->pergroups = NULL;
	aggstate->grp_firstTuple = NULL;
	aggstate->sort_in = NULL;
	aggstate->sort_out = NULL;
	aggstate->aggs_used = NULL;