explain.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

	}

	appendStringInfoString(str, pname);
	switch (nodeTag(plan))
	{
		case T_IndexScan:
			if (ScanDirectionIsBackward(((IndexScan *) plan)->indexorderdir))
				appendStringInfoString(str, " Backward");
			appendStringInfo(str, " using %s",
			  quote_identifier(get_rel_name(((IndexScan *) plan)->indexid)));
			/* FALL THRU */
		case T_SeqScan:
		case T_BitmapHeapScan:
		case T_TidScan:
			if (((Scan *) plan)->scanrelid > 0)
			{
				RangeTblEntry *rte = rt_fetch(((Scan *) plan)->scanrelid,
											  es->rtable);
				char	   *relname;

				/* Assume it's on a real relation */
				Assert(rte->rtekind == RTE_RELATION);

				/* We only show the rel name, not schema name */
				relname = get_rel_name(rte->relid);

				appendStringInfo(str, " on %s",
								 quote_identifier(relname));
				if (strcmp(rte->eref->aliasname, relname) != 0)
					appendStringInfo(str, " %s",
									 quote_identifier(rte->eref->aliasname));
			}
			break;
		case T_BitmapIndexScan:
			appendStringInfo(str, " on %s",
							 quote_identifier(get_rel_name(((BitmapIndexScan *) plan)->indexid)));
			break;
		case T_SubqueryScan:
			if (((Scan *) plan)->scanrelid > 0)
			{
				RangeTblEntry *rte = rt_fetch(((Scan *) plan)->scanrelid,
											  es->rtable);

				appendStringInfo(str, " %s",
								 quote_identifier(rte->eref->aliasname));
			}
			break;
		case T_FunctionScan:
			if (((Scan *) plan)->scanrelid > 0)
			{
				RangeTblEntry *rte = rt_fetch(((Scan *) plan)->scanrelid,
											  es->rtable);
				char	   *proname;

				/* Assert it's on a RangeFunction */
				Assert(rte->rtekind == RTE_FUNCTION);

				/*
				 * If the expression is still a function call, we can get the
				 * real name of the function.  Otherwise, punt (this can
				 * happen if the optimizer simplified away the function call,
				 * for example).
				 */
				if (rte->funcexpr && IsA(rte->funcexpr, FuncExpr))
				{
					FuncExpr   *funcexpr = (FuncExpr *) rte->funcexpr;
					Oid			funcid = funcexpr->funcid;

					/* We only show the func name, not schema name */
					proname = get_func_name(funcid);
				}
				else
					proname = rte->eref->aliasname;

				appendStringInfo(str, " on %s",
								 quote_identifier(proname));
				if (strcmp(rte->eref->aliasname, proname) != 0)
					appendStringInfo(str, " %s",
									 quote_identifier(rte->eref->aliasname));
			}
			break;
		default:
			break;
	}

	appendStringInfo(str, "  (cost=%.2f..%.2f rows=%.0f width=%d)",
					 plan->startup_cost, plan->total_cost,
					 plan->plan_rows, plan->plan_width);

	/*
	 * We have to forcibly clean up the instrumentation state because we
	 * haven't done ExecutorEnd yet.  This is pretty grotty ...
	 */
	if (planstate->instrument)
		InstrEndLoop(planstate->instrument);

	if (planstate->instrument && planstate->instrument->nloops > 0)
	{
		double		nloops = planstate->instrument->nloops;

		appendStringInfo(str, " (actual time=%.3f..%.3f rows=%.0f loops=%.0f)",
						 1000.0 * planstate->instrument->startup / nloops,
						 1000.0 * planstate->instrument->total / nloops,
						 planstate->instrument->ntuples / nloops,
						 planstate->instrument->nloops);
	}
	else if (es->printAnalyze)
		appendStringInfo(str, " (never executed)");
	appendStringInfoChar(str, '\n');

	/* quals, sort keys, etc */
	switch (nodeTag(plan))
	{
		case T_IndexScan:
			show_scan_qual(((IndexScan *) plan)->indexqualorig,
						   "Index Cond",
						   ((Scan *) plan)->scanrelid,
						   outer_plan,
						   str, indent, es);
			show_scan_qual(plan->qual,
						   "Filter",
						   ((Scan *) plan)->scanrelid,
						   outer_plan,
						   str, indent, es);
			break;
		case T_BitmapIndexScan:
			show_scan_qual(((BitmapIndexScan *) plan)->indexqualorig,
						   "Index Cond",
						   ((Scan *) plan)->scanrelid,
						   outer_plan,
						   str, indent, es);
			break;
		case T_BitmapHeapScan:
			/* XXX do we want to show this in production? */
			show_scan_qual(((BitmapHeapScan *) plan)->bitmapqualorig,
						   "Recheck Cond",
						   ((Scan *) plan)->scanrelid,
						   outer_plan,
						   str, indent, es);
			/* FALL THRU */
		case T_SeqScan:
		case T_TidScan:
		case T_SubqueryScan:
		case T_FunctionScan:
			show_scan_qual(plan->qual,
						   "Filter",
						   ((Scan *) plan)->scanrelid,
						   outer_plan,
						   str, indent, es);
			break;
		case T_NestLoop:
			show_upper_qual(((NestLoop *) plan)->join.joinqual,
							"Join Filter",
							"outer", OUTER, outerPlan(plan),
							"inner", INNER, innerPlan(plan),
							str, indent, es);
			show_upper_qual(plan->qual,
							"Filter",
							"outer", OUTER, outerPlan(plan),
							"inner", INNER, innerPlan(plan),
							str, indent, es);
			break;
		case T_MergeJoin:
			show_upper_qual(((MergeJoin *) plan)->mergeclauses,
							"Merge Cond",
							"outer", OUTER, outerPlan(plan),
							"inner", INNER, innerPlan(plan),
							str, indent, es);
			show_upper_qual(((MergeJoin *) plan)->join.joinqual,
							"Join Filter",
							"outer", OUTER, outerPlan(plan),
							"inner", INNER, innerPlan(plan),
							str, indent, es);
			show_upper_qual(plan->qual,
							"Filter",
							"outer", OUTER, outerPlan(plan),
							"inner", INNER, innerPlan(plan),
							str, indent, es);
			break;
		case T_HashJoin:
			show_upper_qual(((HashJoin *) plan)->hashclauses,
							"Hash Cond",
							"outer", OUTER, outerPlan(plan),
							"inner", INNER, innerPlan(plan),
							str, indent, es);
			show_upper_qual(((HashJoin *) plan)->join.joinqual,
							"Join Filter",
							"outer", OUTER, outerPlan(plan),
							"inner", INNER, innerPlan(plan),
							str, indent, es);
			show_upper_qual(plan->qual,
							"Filter",
							"outer", OUTER, outerPlan(plan),
							"inner", INNER, innerPlan(plan),
							str, indent, es);
			break;
		case T_Agg:
		case T_Group:
			show_upper_qual(plan->qual,
							"Filter",
							"subplan", 0, outerPlan(plan),
							"", 0, NULL,
							str, indent, es);
			break;
		case T_Sort:
			show_sort_keys(plan->targetlist,
						   ((Sort *) plan)->numCols,
						   ((Sort *) plan)->sortColIdx,
						   "Sort Key",
						   str, indent, es);
			break;
		case T_Result:
			show_upper_qual((List *) ((Result *) plan)->resconstantqual,
							"One-Time Filter",
							"subplan", OUTER, outerPlan(plan),
							"", 0, NULL,
							str, indent, es);
			show_upper_qual(plan->qual,
							"Filter",
							"subplan", OUTER, outerPlan(plan),
							"", 0, NULL,
							str, indent, es);
			break;
		default:
			break;
	}

	/* initPlan-s */
	if (plan->initPlan)
	{
		List	   *saved_rtable = es->rtable;
		ListCell   *lst;

		for (i = 0; i < indent; i++)
			appendStringInfo(str, "  ");
		appendStringInfo(str, "  InitPlan\n");
		foreach(lst, planstate->initPlan)
		{
			SubPlanState *sps = (SubPlanState *) lfirst(lst);
			SubPlan    *sp = (SubPlan *) sps->xprstate.expr;

			es->rtable = sp->rtable;
			for (i = 0; i < indent; i++)
				appendStringInfo(str, "  ");
			appendStringInfo(str, "    ->  ");
			explain_outNode(str, sp->plan,
							sps->planstate,
							NULL,
							indent + 4, es);
		}
		es->rtable = saved_rtable;
	}

	/* lefttree */
	if (outerPlan(plan))
	{
		for (i = 0; i < indent; i++)
			appendStringInfo(str, "  ");
		appendStringInfo(str, "  ->  ");

		/*
		 * Ordinarily we don't pass down our own outer_plan value to our child
		 * nodes, but in bitmap scan trees we must, since the bottom
		 * BitmapIndexScan nodes may have outer references.
		 */
		explain_outNode(str, outerPlan(plan),
						outerPlanState(planstate),
						IsA(plan, BitmapHeapScan) ? outer_plan : NULL,
						indent + 3, es);
	}

	/* righttree */
	if (innerPlan(plan))
	{
		for (i = 0; i < indent; i++)
			appendStringInfo(str, "  ");
		appendStringInfo(str, "  ->  ");
		explain_outNode(str, innerPlan(plan),
						innerPlanState(planstate),
						outerPlan(plan),
						indent + 3, es);
	}

	if (IsA(plan, Append))
	{
		Append	   *appendplan = (Append *) plan;
		AppendState *appendstate = (AppendState *) planstate;
		ListCell   *lst;
		int			j;

		j = 0;
		foreach(lst, appendplan->appendplans)
		{
			Plan	   *subnode = (Plan *) lfirst(lst);

			for (i = 0; i < indent; i++)
				appendStringInfo(str, "  ");
			appendStringInfo(str, "  ->  ");

			explain_outNode(str, subnode,
							appendstate->appendplans[j],
							NULL,
							indent + 3, es);
			j++;
		}
	}

	if (IsA(plan, BitmapAnd))
	{
		BitmapAnd  *bitmapandplan = (BitmapAnd *) plan;
		BitmapAndState *bitmapandstate = (BitmapAndState *) planstate;
		ListCell   *lst;
		int			j;

		j = 0;
		foreach(lst, bitmapandplan->bitmapplans)
		{
			Plan	   *subnode = (Plan *) lfirst(lst);

			for (i = 0; i < indent; i++)
				appendStringInfo(str, "  ");
			appendStringInfo(str, "  ->  ");

			explain_outNode(str, subnode,
							bitmapandstate->bitmapplans[j],
							outer_plan, /* pass down same outer plan */
							indent + 3, es);
			j++;
		}
	}

	if (IsA(plan, BitmapOr))
	{
		BitmapOr   *bitmaporplan = (BitmapOr *) plan;
		BitmapOrState *bitmaporstate = (BitmapOrState *) planstate;
		ListCell   *lst;
		int			j;

		j = 0;
		foreach(lst, bitmaporplan->bitmapplans)
		{
			Plan	   *subnode = (Plan *) lfirst(lst);

			for (i = 0; i < indent; i++)
				appendStringInfo(str, "  ");
			appendStringInfo(str, "  ->  ");

			explain_outNode(str, subnode,
							bitmaporstate->bitmapplans[j],
							outer_plan, /* pass down same outer plan */
							indent + 3, es);
			j++;
		}
	}

	if (IsA(plan, SubqueryScan))
	{
		SubqueryScan *subqueryscan = (SubqueryScan *) plan;
		SubqueryScanState *subquerystate = (SubqueryScanState *) planstate;
		Plan	   *subnode = subqueryscan->subplan;
		RangeTblEntry *rte = rt_fetch(subqueryscan->scan.scanrelid,
									  es->rtable);
		List	   *saved_rtable = es->rtable;

		Assert(rte->rtekind == RTE_SUBQUERY);
		es->rtable = rte->subquery->rtable;

		for (i = 0; i < indent; i++)
			appendStringInfo(str, "  ");
		appendStringInfo(str, "  ->  ");

		explain_outNode(str, subnode,
						subquerystate->subplan,
						NULL,
						indent + 3, es);

		es->rtable = saved_rtable;
	}

	/* subPlan-s */
	if (planstate->subPlan)
	{
		List	   *saved_rtable = es->rtable;
		ListCell   *lst;

		for (i = 0; i < indent; i++)
			appendStringInfo(str, "  ");
		appendStringInfo(str, "  SubPlan\n");
		foreach(lst, planstate->subPlan)
		{
			SubPlanState *sps = (SubPlanState *) lfirst(lst);
			SubPlan    *sp = (SubPlan *) sps->xprstate.expr;

			es->rtable = sp->rtable;
			for (i = 0; i < indent; i++)
				appendStringInfo(str, "  ");
			appendStringInfo(str, "    ->  ");
			explain_outNode(str, sp->plan,
							sps->planstate,
							NULL,
							indent + 4, es);
		}
		es->rtable = saved_rtable;
	}
}

/*
 * Show a qualifier expression for a scan plan node
 */
static void
show_scan_qual(List *qual, const char *qlabel,
			   int scanrelid, Plan *outer_plan,
			   StringInfo str, int indent, ExplainState *es)
{
	RangeTblEntry *rte;
	Node	   *scancontext;
	Node	   *outercontext;
	List	   *context;
	Node	   *node;
	char	   *exprstr;
	int			i;

	/* No work if empty qual */
	if (qual == NIL)
		return;

	/* Convert AND list to explicit AND */
	node = (Node *) make_ands_explicit(qual);

	/* Generate deparse context */
	Assert(scanrelid > 0 && scanrelid <= list_length(es->rtable));
	rte = rt_fetch(scanrelid, es->rtable);
	scancontext = deparse_context_for_rte(rte);

	/*
	 * If we have an outer plan that is referenced by the qual, add it to the
	 * deparse context.  If not, don't (so that we don't force prefixes
	 * unnecessarily).
	 */
	if (outer_plan)
	{
		Relids		varnos = pull_varnos(node);

		if (bms_is_member(OUTER, varnos))
			outercontext = deparse_context_for_subplan("outer",
													   outer_plan->targetlist,
													   es->rtable);
		else
			outercontext = NULL;
		bms_free(varnos);
	}
	else
		outercontext = NULL;

	context = deparse_context_for_plan(scanrelid, scancontext,
									   OUTER, outercontext,
									   NIL);

	/* Deparse the expression */
	exprstr = deparse_expression(node, context, (outercontext != NULL), false);

	/* And add to str */
	for (i = 0; i < indent; i++)
		appendStringInfo(str, "  ");
	appendStringInfo(str, "  %s: %s\n", qlabel, exprstr);
}

/*
 * Show a qualifier expression for an upper-level plan node
 */
static void
show_upper_qual(List *qual, const char *qlabel,
				const char *outer_name, int outer_varno, Plan *outer_plan,
				const char *inner_name, int inner_varno, Plan *inner_plan,
				StringInfo str, int indent, ExplainState *es)
{
	List	   *context;
	Node	   *outercontext;
	Node	   *innercontext;
	Node	   *node;
	char	   *exprstr;
	int			i;

	/* No work if empty qual */
	if (qual == NIL)
		return;

	/* Generate deparse context */
	if (outer_plan)
		outercontext = deparse_context_for_subplan(outer_name,
												   outer_plan->targetlist,
												   es->rtable);
	else
		outercontext = NULL;
	if (inner_plan)
		innercontext = deparse_context_for_subplan(inner_name,
												   inner_plan->targetlist,
												   es->rtable);
	else
		innercontext = NULL;
	context = deparse_context_for_plan(outer_varno, outercontext,
									   inner_varno, innercontext,
									   NIL);

	/* Deparse the expression */
	node = (Node *) make_ands_explicit(qual);
	exprstr = deparse_expression(node, context, (inner_plan != NULL), false);

	/* And add to str */
	for (i = 0; i < indent; i++)
		appendStringInfo(str, "  ");
	appendStringInfo(str, "  %s: %s\n", qlabel, exprstr);
}

/*
 * Show the sort keys for a Sort node.
 */
static void
show_sort_keys(List *tlist, int nkeys, AttrNumber *keycols,
			   const char *qlabel,
			   StringInfo str, int indent, ExplainState *es)
{
	List	   *context;
	bool		useprefix;
	int			keyno;
	char	   *exprstr;
	Relids		varnos;
	int			i;

	if (nkeys <= 0)
		return;

	for (i = 0; i < indent; i++)
		appendStringInfo(str, "  ");
	appendStringInfo(str, "  %s: ", qlabel);

	/*
	 * In this routine we expect that the plan node's tlist has not been
	 * processed by set_plan_references().	Normally, any Vars will contain
	 * valid varnos referencing the actual rtable.	But we might instead be
	 * looking at a dummy tlist generated by prepunion.c; if there are Vars
	 * with zero varno, use the tlist itself to determine their names.
	 */
	varnos = pull_varnos((Node *) tlist);
	if (bms_is_member(0, varnos))
	{
		Node	   *outercontext;

		outercontext = deparse_context_for_subplan("sort",
												   tlist,
												   es->rtable);
		context = deparse_context_for_plan(0, outercontext,
										   0, NULL,
										   NIL);
		useprefix = false;
	}
	else
	{
		context = deparse_context_for_plan(0, NULL,
										   0, NULL,
										   es->rtable);
		useprefix = list_length(es->rtable) > 1;
	}
	bms_free(varnos);

	for (keyno = 0; keyno < nkeys; keyno++)
	{
		/* find key expression in tlist */
		AttrNumber	keyresno = keycols[keyno];
		TargetEntry *target = get_tle_by_resno(tlist, keyresno);

		if (!target)
			elog(ERROR, "no tlist entry for key %d", keyresno);
		/* Deparse the expression, showing any top-level cast */
		exprstr = deparse_expression((Node *) target->expr, context,
									 useprefix, true);
		/* And add to str */
		if (keyno > 0)
			appendStringInfo(str, ", ");
		appendStringInfoString(str, exprstr);
	}

	appendStringInfo(str, "\n");
}