C++ IsA函数代码示例

//.........这里部分代码省略.........
	Assert(rootIdx == 0 ||
		   (rootIdx > sliceTbl->nMotions
			&& rootIdx <= sliceTbl->nMotions + sliceTbl->nInitPlans));

	/*
	 * Keep old value so we can restore it. We use this field as a parameter.
	 */
	oldLocalSlice = sliceTbl->localSlice;

	/*
	 * This function is called only for planned statements.
	 */
	stmt = queryDesc->plannedstmt;
	Assert(stmt);

	/*
	 * Let's evaluate STABLE functions now, so we get consistent values on the QEs
	 *
	 * Also, if this is a single-row INSERT statement, let's evaluate
	 * nextval() and currval() now, so that we get the QD's values, and a
	 * consistent value for everyone
	 *
	 */
	is_SRI = false;

	if (queryDesc->operation == CMD_INSERT)
	{
		Assert(stmt->commandType == CMD_INSERT);

		/*
		 * We might look for constant input relation (instead of SRI), but I'm afraid
		 * * that wouldn't scale.
		 */
		is_SRI = IsA(stmt->planTree, Result)
			&& stmt->planTree->lefttree == NULL;
	}

	if (!is_SRI)
		clear_relsize_cache();

	if (queryDesc->operation == CMD_INSERT ||
		queryDesc->operation == CMD_SELECT ||
		queryDesc->operation == CMD_UPDATE ||
		queryDesc->operation == CMD_DELETE)
	{

		MemoryContext oldContext;

		oldContext = CurrentMemoryContext;
		if (stmt->qdContext)
		{
			oldContext = MemoryContextSwitchTo(stmt->qdContext);
		}
		else
		/*
		 * memory context of plan tree should not change
		 */
		{
			MemoryContext mc = GetMemoryChunkContext(stmt->planTree);

			oldContext = MemoryContextSwitchTo(mc);
		}

		stmt->planTree = (Plan *) exec_make_plan_constant(stmt, is_SRI);

		MemoryContextSwitchTo(oldContext);

//.........这里部分代码省略.........
		Oid			func;
		Oid			element_type;
		int16		elmlen;
		bool		elmbyval;
		char		elmalign;
		char		elmdelim;
		Oid			elmioparam;
		Datum	   *elems;
		bool	   *nulls;
		int			dims[1];
		int			lbs[1];
		ArrayType  *arry;

		nfixedarg = i;
		element_type = pp->provariadic;

		/*
		 * Get info about element type, including its input conversion proc
		 */
		get_type_io_data(element_type, IOFunc_input,
						 &elmlen, &elmbyval, &elmalign, &elmdelim,
						 &elmioparam, &func);

		elems = (Datum *) palloc(function.nvargs * sizeof(Datum));
		nulls = (bool *) palloc0(function.nvargs * sizeof(bool));
		for (i = 0; i < function.nvargs; i++)
		{
			if (function.args[nfixedarg + i] == NULL)
				nulls[i] = true;
			else
			{
				elems[i] = OidInputFunctionCall(func,
								(char *) function.args[nfixedarg + i], elmioparam, -1);
				pfree(function.args[nfixedarg + i]);
			}
		}

		dims[0] = function.nvargs;
		lbs[0] = 1;
		arry = construct_md_array(elems, nulls, 1, dims, lbs, element_type,
								  elmlen, elmbyval, elmalign);
		self->fcinfo.arg[nfixedarg] = PointerGetDatum(arry);
	}

	/*
	 * assign default arguments
	 */
	if (function.ndargs > 0)
	{
		Datum		proargdefaults;
		bool		isnull;
		char	   *str;
		List	   *defaults;
		int			ndelete;
		ListCell   *l;

		/* shouldn't happen, FuncnameGetCandidates messed up */
		if (function.ndargs > pp->pronargdefaults)
			elog(ERROR, "not enough default arguments");

		proargdefaults = SysCacheGetAttr(PROCOID, ftup,
										 Anum_pg_proc_proargdefaults,
										 &isnull);
		Assert(!isnull);
		str = TextDatumGetCString(proargdefaults);
		defaults = (List *) stringToNode(str);
		Assert(IsA(defaults, List));
		pfree(str);
		/* Delete any unused defaults from the returned list */
		ndelete = list_length(defaults) - function.ndargs;
		while (ndelete-- > 0)
			defaults = list_delete_first(defaults);

		self->arg_econtext = CreateStandaloneExprContext();
		foreach(l, defaults)
		{
			Expr	   *expr = (Expr *) lfirst(l);
			ExprState  *argstate;
			ExprDoneCond thisArgIsDone;

			/* probably shouldn't happen ... */
			if (nargs >= FUNC_MAX_ARGS)
				ereport(ERROR,
						(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
				 errmsg("cannot pass more than %d arguments to a function", FUNC_MAX_ARGS)));

			argstate = ExecInitExpr(expr, NULL);

			self->fcinfo.arg[nargs] = ExecEvalExpr(argstate,
												   self->arg_econtext,
												   &self->fcinfo.argnull[nargs],
												   &thisArgIsDone);

			if (thisArgIsDone != ExprSingleResult)
				ereport(ERROR,
						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
						 errmsg("functions and operators can take at most one set argument")));

			nargs++;
		}

/*
 * This function executes set evaluation.  The parser sets up a set reference
 * as a call to this function with the OID of the set to evaluate as argument.
 *
 * We build a new fcache for execution of the set's function and run the
 * function until it says "no mas".  The fn_extra field of the call's
 * FmgrInfo record is a handy place to hold onto the fcache.  (Since this
 * is a built-in function, there is no competing use of fn_extra.)
 */
Datum
seteval(PG_FUNCTION_ARGS)
{
	Oid			funcoid = PG_GETARG_OID(0);
	FuncExprState *fcache;
	Datum		result;
	bool		isNull;
	ExprDoneCond isDone;

	/*
	 * If this is the first call, we need to set up the fcache for the
	 * target set's function.
	 */
	fcache = (FuncExprState *) fcinfo->flinfo->fn_extra;
	if (fcache == NULL)
	{
		MemoryContext oldcontext;
		FuncExpr   *func;

		oldcontext = MemoryContextSwitchTo(fcinfo->flinfo->fn_mcxt);

		func = makeNode(FuncExpr);
		func->funcid = funcoid;
		func->funcresulttype = InvalidOid;		/* nothing will look at
												 * this */
		func->funcretset = true;
		func->funcformat = COERCE_EXPLICIT_CALL;
		func->args = NIL;		/* there are no arguments */

		fcache = (FuncExprState *) ExecInitExpr((Expr *) func, NULL);

		MemoryContextSwitchTo(oldcontext);

		init_fcache(funcoid, fcache, fcinfo->flinfo->fn_mcxt);

		fcinfo->flinfo->fn_extra = (void *) fcache;
	}

	/*
	 * Evaluate the function.  NOTE: we need no econtext because there are
	 * no arguments to evaluate.
	 */

	/* ExecMakeFunctionResult assumes these are initialized at call: */
	isNull = false;
	isDone = ExprSingleResult;

	result = ExecMakeFunctionResult(fcache,
									NULL,		/* no econtext, see above */
									&isNull,
									&isDone);

	/*
	 * Return isNull/isDone status.
	 */
	fcinfo->isnull = isNull;

	if (isDone != ExprSingleResult)
	{
		ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;

		if (rsi && IsA(rsi, ReturnSetInfo))
			rsi->isDone = isDone;
		else
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("set-valued function called in context that "
							"cannot accept a set")));
	}

	PG_RETURN_DATUM(result);
}

/*
 * PerformCursorOpen
 *		Execute SQL DECLARE CURSOR command.
 *
 * The query has already been through parse analysis, rewriting, and planning.
 * When it gets here, it looks like a SELECT PlannedStmt, except that the
 * utilityStmt field is set.
 */
void
PerformCursorOpen(PlannedStmt *stmt, ParamListInfo params,
				  const char *queryString, bool isTopLevel)
{
	DeclareCursorStmt *cstmt = (DeclareCursorStmt *) stmt->utilityStmt;
	Portal		portal;
	MemoryContext oldContext;

	if (cstmt == NULL || !IsA(cstmt, DeclareCursorStmt))
		elog(ERROR, "PerformCursorOpen called for non-cursor query");

	/*
	 * Disallow empty-string cursor name (conflicts with protocol-level
	 * unnamed portal).
	 */
	if (!cstmt->portalname || cstmt->portalname[0] == '\0')
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_CURSOR_NAME),
				 errmsg("invalid cursor name: must not be empty")));

	/*
	 * If this is a non-holdable cursor, we require that this statement has
	 * been executed inside a transaction block (or else, it would have no
	 * user-visible effect).
	 */
	if (!(cstmt->options & CURSOR_OPT_HOLD))
		RequireTransactionChain(isTopLevel, "DECLARE CURSOR");

	/*
	 * Create a portal and copy the plan and queryString into its memory.
	 */
	portal = CreatePortal(cstmt->portalname, false, false);

	oldContext = MemoryContextSwitchTo(PortalGetHeapMemory(portal));

	stmt = copyObject(stmt);
	stmt->utilityStmt = NULL;	/* make it look like plain SELECT */

	queryString = pstrdup(queryString);

	PortalDefineQuery(portal,
					  NULL,
					  queryString,
					  "SELECT", /* cursor's query is always a SELECT */
					  list_make1(stmt),
					  NULL);

	/*----------
	 * Also copy the outer portal's parameter list into the inner portal's
	 * memory context.	We want to pass down the parameter values in case we
	 * had a command like
	 *		DECLARE c CURSOR FOR SELECT ... WHERE foo = $1
	 * This will have been parsed using the outer parameter set and the
	 * parameter value needs to be preserved for use when the cursor is
	 * executed.
	 *----------
	 */
	params = copyParamList(params);

	MemoryContextSwitchTo(oldContext);

	/*
	 * Set up options for portal.
	 *
	 * If the user didn't specify a SCROLL type, allow or disallow scrolling
	 * based on whether it would require any additional runtime overhead to do
	 * so.	Also, we disallow scrolling for FOR UPDATE cursors.
	 */
	portal->cursorOptions = cstmt->options;
	if (!(portal->cursorOptions & (CURSOR_OPT_SCROLL | CURSOR_OPT_NO_SCROLL)))
	{
		if (stmt->rowMarks == NIL &&
			ExecSupportsBackwardScan(stmt->planTree))
			portal->cursorOptions |= CURSOR_OPT_SCROLL;
		else
			portal->cursorOptions |= CURSOR_OPT_NO_SCROLL;
	}

	/*
	 * Start execution, inserting parameters if any.
	 */
	PortalStart(portal, params, 0, GetActiveSnapshot());

	Assert(portal->strategy == PORTAL_ONE_SELECT);

	/*
	 * We're done; the query won't actually be run until PerformPortalFetch is
	 * called.
	 */
}

void
parseHwParameters(List *parameterList, HoltWintersModel *specificModel) {
	ListCell				*cell;
	foreach(cell,parameterList) {
		AlgorithmParameter		*param = lfirst(cell);

		/* Seasonflag*/
		if(strcmp(param->key,"has_season") == 0) {
			if(IsA(&(param->value->val),Integer)) {
				specificModel->doseasonal = intVal(&param->value->val);
				specificModel->optflag[2]=specificModel->doseasonal;
			} else
				ereport(ERROR,
				        (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				         errmsg("Parameter value has to be an Integer value"),
				         errposition(param->value->location)));
		} else if(strcmp(param->key,"has_trend") == 0) {
			if(IsA(&(param->value->val),Integer)) {
				specificModel->dotrend = intVal(&param->value->val);
				specificModel->optflag[1]=specificModel->dotrend;
			} else
				ereport(ERROR,
				        (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				         errmsg("Parameter value has to be an Integer value"),
				         errposition(param->value->location)));
					
		} else if(strcmp(param->key,"seasontype") == 0) {
			if(IsA(&(param->value->val),Integer)) {
				specificModel->seasonType = intVal(&param->value->val);
			} else
				ereport(ERROR,
				        (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				         errmsg("Parameter value has to be an Integer value"),
				         errposition(param->value->location)));
					
		} else if(strcmp(param->key,"alpha") == 0) {
			if(IsA(&(param->value->val),Float)) {
				specificModel->alpha = floatVal(&param->value->val);
				specificModel->optflag[0]=0;
			} else
				ereport(ERROR,
				        (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				         errmsg("Parameter value has to be an float value"),
				         errposition(param->value->location)));
					
		}else if(strcmp(param->key,"beta") == 0) {
			if(IsA(&(param->value->val),Float)) {
				specificModel->beta = floatVal(&param->value->val);
				specificModel->optflag[1]=0;
				specificModel->dotrend=1;
			} else
				ereport(ERROR,
				        (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				         errmsg("Parameter value has to be an float value"),
				         errposition(param->value->location)));
					
		}else if(strcmp(param->key,"gamma") == 0) {
			if(IsA(&(param->value->val),Float)) {
				specificModel->gamma = floatVal(&param->value->val);
				specificModel->optflag[2]=0;
				specificModel->doseasonal=1;
			} else
				ereport(ERROR,
				        (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				         errmsg("Parameter value has to be an float value"),
				         errposition(param->value->location)));
					
		}else if(strcmp(param->key,"season") == 0) {
			if(IsA(&(param->value->val),Integer)) {
				specificModel->period = intVal(&param->value->val);
				specificModel->doseasonal = 1;
				specificModel->optflag[2]=specificModel->doseasonal;
			} else
				ereport(ERROR,
				        (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				         errmsg("Parameter value has to be an Integer value"),
				         errposition(param->value->location)));
		}  else if(strcmp(param->key,"error") == 0) {
			if(IsA(&(param->value->val),String)) {
				specificModel->errorfunction = palloc0((strlen(strVal(&param->value->val))+1)*sizeof(char));
				strcpy(specificModel->errorfunction,strVal(&param->value->val));
			} else
				ereport(ERROR,
				        (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
				         errmsg("Parameter value has to be an String value"),
				         errposition(param->value->location)));
		} else
			ereport(WARNING,
			        (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
			         errmsg("Parameter not known"),
			         errposition(((A_Const *)param->value)->location)));
	}

/*
 * internal_get_result_type -- workhorse code implementing all the above
 *
 * funcid must always be supplied.  call_expr and rsinfo can be NULL if not
 * available.  We will return TYPEFUNC_RECORD, and store NULL into
 * *resultTupleDesc, if we cannot deduce the complete result rowtype from
 * the available information.
 */
static TypeFuncClass
internal_get_result_type(Oid funcid,
						 Node *call_expr,
						 ReturnSetInfo *rsinfo,
						 Oid *resultTypeId,
						 TupleDesc *resultTupleDesc)
{
	TypeFuncClass result;
	HeapTuple	tp;
	Form_pg_proc procform;
	Oid			rettype;
	TupleDesc	tupdesc;

	/* First fetch the function's pg_proc row to inspect its rettype */
	tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
	if (!HeapTupleIsValid(tp))
		elog(ERROR, "cache lookup failed for function %u", funcid);
	procform = (Form_pg_proc) GETSTRUCT(tp);

	rettype = procform->prorettype;

	/* Check for OUT parameters defining a RECORD result */
	tupdesc = build_function_result_tupdesc_t(tp);
	if (tupdesc)
	{
		/*
		 * It has OUT parameters, so it's basically like a regular composite
		 * type, except we have to be able to resolve any polymorphic OUT
		 * parameters.
		 */
		if (resultTypeId)
			*resultTypeId = rettype;

		if (resolve_polymorphic_tupdesc(tupdesc,
										&procform->proargtypes,
										call_expr))
		{
			if (tupdesc->tdtypeid == RECORDOID &&
				tupdesc->tdtypmod < 0)
				assign_record_type_typmod(tupdesc);
			if (resultTupleDesc)
				*resultTupleDesc = tupdesc;
			result = TYPEFUNC_COMPOSITE;
		}
		else
		{
			if (resultTupleDesc)
				*resultTupleDesc = NULL;
			result = TYPEFUNC_RECORD;
		}

		ReleaseSysCache(tp);

		return result;
	}

	/*
	 * If scalar polymorphic result, try to resolve it.
	 */
	if (IsPolymorphicType(rettype))
	{
		Oid			newrettype = exprType(call_expr);

		if (newrettype == InvalidOid)	/* this probably should not happen */
			ereport(ERROR,
					(errcode(ERRCODE_DATATYPE_MISMATCH),
					 errmsg("could not determine actual result type for function \"%s\" declared to return type %s",
							NameStr(procform->proname),
							format_type_be(rettype))));
		rettype = newrettype;
	}

	if (resultTypeId)
		*resultTypeId = rettype;
	if (resultTupleDesc)
		*resultTupleDesc = NULL;	/* default result */

	/* Classify the result type */
	result = get_type_func_class(rettype);
	switch (result)
	{
		case TYPEFUNC_COMPOSITE:
			if (resultTupleDesc)
				*resultTupleDesc = lookup_rowtype_tupdesc_copy(rettype, -1);
			/* Named composite types can't have any polymorphic columns */
			break;
		case TYPEFUNC_SCALAR:
			break;
		case TYPEFUNC_RECORD:
			/* We must get the tupledesc from call context */
			if (rsinfo && IsA(rsinfo, ReturnSetInfo) &&
				rsinfo->expectedDesc != NULL)
//.........这里部分代码省略.........

/*
 *	tsmatchsel -- Selectivity of "@@"
 *
 * restriction selectivity function for tsvector @@ tsquery and
 * tsquery @@ tsvector
 */
Datum
tsmatchsel(PG_FUNCTION_ARGS)
{
	PlannerInfo *root = (PlannerInfo *) PG_GETARG_POINTER(0);

#ifdef NOT_USED
	Oid			operator = PG_GETARG_OID(1);
#endif
	List	   *args = (List *) PG_GETARG_POINTER(2);
	int			varRelid = PG_GETARG_INT32(3);
	VariableStatData vardata;
	Node	   *other;
	bool		varonleft;
	Selectivity selec;

	/*
	 * If expression is not variable = something or something = variable, then
	 * punt and return a default estimate.
	 */
	if (!get_restriction_variable(root, args, varRelid,
								  &vardata, &other, &varonleft))
		PG_RETURN_FLOAT8(DEFAULT_TS_MATCH_SEL);

	/*
	 * Can't do anything useful if the something is not a constant, either.
	 */
	if (!IsA(other, Const))
	{
		ReleaseVariableStats(vardata);
		PG_RETURN_FLOAT8(DEFAULT_TS_MATCH_SEL);
	}

	/*
	 * The "@@" operator is strict, so we can cope with NULL right away
	 */
	if (((Const *) other)->constisnull)
	{
		ReleaseVariableStats(vardata);
		PG_RETURN_FLOAT8(0.0);
	}

	/*
	 * OK, there's a Var and a Const we're dealing with here. We need the Var
	 * to be a TSVector (or else we don't have any useful statistic for it).
	 * We have to check this because the Var might be the TSQuery not the
	 * TSVector.
	 */
	if (vardata.vartype == TSVECTOROID)
	{
		/* tsvector @@ tsquery or the other way around */
		Assert(((Const *) other)->consttype == TSQUERYOID);

		selec = tsquerysel(&vardata, ((Const *) other)->constvalue);
	}
	else
	{
		/* The Var is something we don't have useful statistics for */
		selec = DEFAULT_TS_MATCH_SEL;
	}

	ReleaseVariableStats(vardata);

	CLAMP_PROBABILITY(selec);

	PG_RETURN_FLOAT8((float8) selec);
}

/* ----------------
 *		ExecBuildProjectionInfo
 *
 * Build a ProjectionInfo node for evaluating the given tlist in the given
 * econtext, and storing the result into the tuple slot.  (Caller must have
 * ensured that tuple slot has a descriptor matching the tlist!)  Note that
 * the given tlist should be a list of ExprState nodes, not Expr nodes.
 *
 * inputDesc can be NULL, but if it is not, we check to see whether simple
 * Vars in the tlist match the descriptor.	It is important to provide
 * inputDesc for relation-scan plan nodes, as a cross check that the relation
 * hasn't been changed since the plan was made.  At higher levels of a plan,
 * there is no need to recheck.
 * ----------------
 */
ProjectionInfo *
ExecBuildProjectionInfo(List *targetList,
						ExprContext *econtext,
						TupleTableSlot *slot,
						TupleDesc inputDesc)
{
	ProjectionInfo *projInfo = makeNode(ProjectionInfo);
	int			len = ExecTargetListLength(targetList);
	int		   *workspace;
	int		   *varSlotOffsets;
	int		   *varNumbers;
	int		   *varOutputCols;
	List	   *exprlist;
	int			numSimpleVars;
	bool		directMap;
	ListCell   *tl;

	projInfo->pi_exprContext = econtext;
	projInfo->pi_slot = slot;
	/* since these are all int arrays, we need do just one palloc */
	workspace = (int *) palloc(len * 3 * sizeof(int));
	projInfo->pi_varSlotOffsets = varSlotOffsets = workspace;
	projInfo->pi_varNumbers = varNumbers = workspace + len;
	projInfo->pi_varOutputCols = varOutputCols = workspace + len * 2;
	projInfo->pi_lastInnerVar = 0;
	projInfo->pi_lastOuterVar = 0;
	projInfo->pi_lastScanVar = 0;

	/*
	 * We separate the target list elements into simple Var references and
	 * expressions which require the full ExecTargetList machinery.  To be a
	 * simple Var, a Var has to be a user attribute and not mismatch the
	 * inputDesc.  (Note: if there is a type mismatch then ExecEvalScalarVar
	 * will probably throw an error at runtime, but we leave that to it.)
	 */
	exprlist = NIL;
	numSimpleVars = 0;
	directMap = true;
	foreach(tl, targetList)
	{
		GenericExprState *gstate = (GenericExprState *) lfirst(tl);
		Var		   *variable = (Var *) gstate->arg->expr;
		bool		isSimpleVar = false;

		if (variable != NULL &&
			IsA(variable, Var) &&
			variable->varattno > 0)
		{
			if (!inputDesc)
				isSimpleVar = true;		/* can't check type, assume OK */
			else if (variable->varattno <= inputDesc->natts)
			{
				Form_pg_attribute attr;

				attr = inputDesc->attrs[variable->varattno - 1];
				if (!attr->attisdropped && variable->vartype == attr->atttypid)
					isSimpleVar = true;
			}
		}

		if (isSimpleVar)
		{
			TargetEntry *tle = (TargetEntry *) gstate->xprstate.expr;
			AttrNumber	attnum = variable->varattno;

			varNumbers[numSimpleVars] = attnum;
			varOutputCols[numSimpleVars] = tle->resno;
			if (tle->resno != numSimpleVars + 1)
				directMap = false;

			switch (variable->varno)
			{
				case INNER_VAR:
					varSlotOffsets[numSimpleVars] = offsetof(ExprContext,
															 ecxt_innertuple);
					if (projInfo->pi_lastInnerVar < attnum)
						projInfo->pi_lastInnerVar = attnum;
					break;

				case OUTER_VAR:
					varSlotOffsets[numSimpleVars] = offsetof(ExprContext,
															 ecxt_outertuple);
					if (projInfo->pi_lastOuterVar < attnum)
						projInfo->pi_lastOuterVar = attnum;
					break;
//.........这里部分代码省略.........

/* ----------------------------------------------------------------
 *		ExecInitCteScan
 * ----------------------------------------------------------------
 */
CteScanState *
ExecInitCteScan(CteScan *node, EState *estate, int eflags)
{
	CteScanState *scanstate;
	ParamExecData *prmdata;

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

	/*
	 * For the moment we have to force the tuplestore to allow REWIND, because
	 * we might be asked to rescan the CTE even though upper levels didn't
	 * tell us to be prepared to do it efficiently.  Annoying, since this
	 * prevents truncation of the tuplestore.  XXX FIXME
	 */
	eflags |= EXEC_FLAG_REWIND;

	/*
	 * CteScan should not have any children.
	 */
	Assert(outerPlan(node) == NULL);
	Assert(innerPlan(node) == NULL);

	/*
	 * create new CteScanState for node
	 */
	scanstate = makeNode(CteScanState);
	scanstate->ss.ps.plan = (Plan *) node;
	scanstate->ss.ps.state = estate;
	scanstate->eflags = eflags;
	scanstate->cte_table = NULL;
	scanstate->eof_cte = false;

	/*
	 * Find the already-initialized plan for the CTE query.
	 */
	scanstate->cteplanstate = (PlanState *) list_nth(estate->es_subplanstates,
													 node->ctePlanId - 1);

	/*
	 * The Param slot associated with the CTE query is used to hold a pointer
	 * to the CteState of the first CteScan node that initializes for this
	 * CTE.  This node will be the one that holds the shared state for all the
	 * CTEs, particularly the shared tuplestore.
	 */
	prmdata = &(estate->es_param_exec_vals[node->cteParam]);
	Assert(prmdata->execPlan == NULL);
	Assert(!prmdata->isnull);
	scanstate->leader = (CteScanState *) DatumGetPointer(prmdata->value);
	if (scanstate->leader == NULL)
	{
		/* I am the leader */
		prmdata->value = PointerGetDatum(scanstate);
		scanstate->leader = scanstate;
		scanstate->cte_table = tuplestore_begin_heap(true, false, work_mem);
		tuplestore_set_eflags(scanstate->cte_table, scanstate->eflags);
		scanstate->readptr = 0;
	}
	else
	{
		/* Not the leader */
		Assert(IsA(scanstate->leader, CteScanState));
		scanstate->readptr =
			tuplestore_alloc_read_pointer(scanstate->leader->cte_table,
										  scanstate->eflags);
	}

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

	/*
	 * initialize child expressions
	 */
	scanstate->ss.ps.targetlist = (List *)
		ExecInitExpr((Expr *) node->scan.plan.targetlist,
					 (PlanState *) scanstate);
	scanstate->ss.ps.qual = (List *)
		ExecInitExpr((Expr *) node->scan.plan.qual,
					 (PlanState *) scanstate);

	/*
	 * tuple table initialization
	 */
	ExecInitResultTupleSlot(estate, &scanstate->ss.ps);
	ExecInitScanTupleSlot(estate, &scanstate->ss);

	/*
	 * The scan tuple type (ie, the rowtype we expect to find in the work
	 * table) is the same as the result rowtype of the CTE query.
	 */
	ExecAssignScanType(&scanstate->ss,
					   ExecGetResultType(scanstate->cteplanstate));
//.........这里部分代码省略.........

/*
 * Helper function for the various SQL callable logical decoding functions.
 */
static Datum
pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool binary)
{
    Name		name;
    XLogRecPtr	upto_lsn;
    int32		upto_nchanges;
    ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
    MemoryContext per_query_ctx;
    MemoryContext oldcontext;
    XLogRecPtr	end_of_wal;
    XLogRecPtr	startptr;
    LogicalDecodingContext *ctx;
    ResourceOwner old_resowner = CurrentResourceOwner;
    ArrayType  *arr;
    Size		ndim;
    List	   *options = NIL;
    DecodingOutputState *p;

    check_permissions();

    CheckLogicalDecodingRequirements();

    if (PG_ARGISNULL(0))
        ereport(ERROR,
                (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
                 errmsg("slot name must not be null")));
    name = PG_GETARG_NAME(0);

    if (PG_ARGISNULL(1))
        upto_lsn = InvalidXLogRecPtr;
    else
        upto_lsn = PG_GETARG_LSN(1);

    if (PG_ARGISNULL(2))
        upto_nchanges = InvalidXLogRecPtr;
    else
        upto_nchanges = PG_GETARG_INT32(2);

    if (PG_ARGISNULL(3))
        ereport(ERROR,
                (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
                 errmsg("options array must not be null")));
    arr = PG_GETARG_ARRAYTYPE_P(3);

    /* check to see if caller supports us returning a tuplestore */
    if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("set-valued function called in context that cannot accept a set")));
    if (!(rsinfo->allowedModes & SFRM_Materialize))
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("materialize mode required, but it is not allowed in this context")));

    /* state to write output to */
    p = palloc0(sizeof(DecodingOutputState));

    p->binary_output = binary;

    /* Build a tuple descriptor for our result type */
    if (get_call_result_type(fcinfo, NULL, &p->tupdesc) != TYPEFUNC_COMPOSITE)
        elog(ERROR, "return type must be a row type");

    per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
    oldcontext = MemoryContextSwitchTo(per_query_ctx);

    /* Deconstruct options array */
    ndim = ARR_NDIM(arr);
    if (ndim > 1)
    {
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("array must be one-dimensional")));
    }
    else if (array_contains_nulls(arr))
    {
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("array must not contain nulls")));
    }
    else if (ndim == 1)
    {
        int			nelems;
        Datum	   *datum_opts;
        int			i;

        Assert(ARR_ELEMTYPE(arr) == TEXTOID);

        deconstruct_array(arr, TEXTOID, -1, false, 'i',
                          &datum_opts, NULL, &nelems);

        if (nelems % 2 != 0)
            ereport(ERROR,
                    (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                     errmsg("array must have even number of elements")));

        for (i = 0; i < nelems; i += 2)
//.........这里部分代码省略.........

/*
 * Compute the list of TIDs to be visited, by evaluating the expressions
 * for them.
 *
 * (The result is actually an array, not a list.)
 */
static void
TidListCreate(TidScanState *tidstate)
{
	List	   *evalList = tidstate->tss_tidquals;
	ExprContext *econtext = tidstate->ss.ps.ps_ExprContext;
	BlockNumber nblocks;
	ItemPointerData *tidList;
	int			numAllocTids;
	int			numTids;
	ListCell   *l;

	/*
	 * We silently discard any TIDs that are out of range at the time of scan
	 * start.  (Since we hold at least AccessShareLock on the table, it won't
	 * be possible for someone to truncate away the blocks we intend to
	 * visit.)
	 */
	nblocks = RelationGetNumberOfBlocks(tidstate->ss.ss_currentRelation);

	/*
	 * We initialize the array with enough slots for the case that all quals
	 * are simple OpExprs or CurrentOfExprs.  If there are any
	 * ScalarArrayOpExprs, we may have to enlarge the array.
	 */
	numAllocTids = list_length(evalList);
	tidList = (ItemPointerData *)
		palloc(numAllocTids * sizeof(ItemPointerData));
	numTids = 0;
	tidstate->tss_isCurrentOf = false;

	foreach(l, evalList)
	{
		ExprState  *exstate = (ExprState *) lfirst(l);
		Expr	   *expr = exstate->expr;
		ItemPointer itemptr;
		bool		isNull;

		if (is_opclause(expr))
		{
			FuncExprState *fexstate = (FuncExprState *) exstate;
			Node	   *arg1;
			Node	   *arg2;

			arg1 = get_leftop(expr);
			arg2 = get_rightop(expr);
			if (IsCTIDVar(arg1))
				exstate = (ExprState *) lsecond(fexstate->args);
			else if (IsCTIDVar(arg2))
				exstate = (ExprState *) linitial(fexstate->args);
			else
				elog(ERROR, "could not identify CTID variable");

			itemptr = (ItemPointer)
				DatumGetPointer(ExecEvalExprSwitchContext(exstate,
														  econtext,
														  &isNull,
														  NULL));
			if (!isNull &&
				ItemPointerIsValid(itemptr) &&
				ItemPointerGetBlockNumber(itemptr) < nblocks)
			{
				if (numTids >= numAllocTids)
				{
					numAllocTids *= 2;
					tidList = (ItemPointerData *)
						repalloc(tidList,
								 numAllocTids * sizeof(ItemPointerData));
				}
				tidList[numTids++] = *itemptr;
			}
		}
		else if (expr && IsA(expr, ScalarArrayOpExpr))
		{
			ScalarArrayOpExprState *saexstate = (ScalarArrayOpExprState *) exstate;
			Datum		arraydatum;
			ArrayType  *itemarray;
			Datum	   *ipdatums;
			bool	   *ipnulls;
			int			ndatums;
			int			i;

			exstate = (ExprState *) lsecond(saexstate->fxprstate.args);
			arraydatum = ExecEvalExprSwitchContext(exstate,
												   econtext,
												   &isNull,
												   NULL);
			if (isNull)
				continue;
			itemarray = DatumGetArrayTypeP(arraydatum);
			deconstruct_array(itemarray,
							  TIDOID, SizeOfIptrData, false, 's',
							  &ipdatums, &ipnulls, &ndatums);
			if (numTids + ndatums > numAllocTids)
			{
//.........这里部分代码省略.........

/*
 * Retrieve statement statistics.
 */
Datum
pg_stat_statements(PG_FUNCTION_ARGS)
{
	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
	TupleDesc	tupdesc;
	Tuplestorestate *tupstore;
	MemoryContext per_query_ctx;
	MemoryContext oldcontext;
	Oid			userid = GetUserId();
	bool		is_superuser = superuser();
	HASH_SEQ_STATUS hash_seq;
	pgssEntry  *entry;

	if (!pgss || !pgss_hash)
		ereport(ERROR,
				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
				 errmsg("pg_stat_statements must be loaded via shared_preload_libraries")));

	/* check to see if caller supports us returning a tuplestore */
	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("set-valued function called in context that cannot accept a set")));
	if (!(rsinfo->allowedModes & SFRM_Materialize))
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("materialize mode required, but it is not " \
						"allowed in this context")));

	/* Build a tuple descriptor for our result type */
	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
		elog(ERROR, "return type must be a row type");

	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
	oldcontext = MemoryContextSwitchTo(per_query_ctx);

	tupstore = tuplestore_begin_heap(true, false, work_mem);
	rsinfo->returnMode = SFRM_Materialize;
	rsinfo->setResult = tupstore;
	rsinfo->setDesc = tupdesc;

	MemoryContextSwitchTo(oldcontext);

	LWLockAcquire(pgss->lock, LW_SHARED);

	hash_seq_init(&hash_seq, pgss_hash);
	while ((entry = hash_seq_search(&hash_seq)) != NULL)
	{
		Datum		values[PG_STAT_STATEMENTS_COLS];
		bool		nulls[PG_STAT_STATEMENTS_COLS];
		int			i = 0;
		Counters	tmp;

		memset(values, 0, sizeof(values));
		memset(nulls, 0, sizeof(nulls));

		values[i++] = ObjectIdGetDatum(entry->key.userid);
		values[i++] = ObjectIdGetDatum(entry->key.dbid);

		if (is_superuser || entry->key.userid == userid)
		{
			char	   *qstr;

			qstr = (char *)
				pg_do_encoding_conversion((unsigned char *) entry->query,
										  entry->key.query_len,
										  entry->key.encoding,
										  GetDatabaseEncoding());
			values[i++] = CStringGetTextDatum(qstr);
			if (qstr != entry->query)
				pfree(qstr);
		}
		else
			values[i++] = CStringGetTextDatum("<insufficient privilege>");

		/* copy counters to a local variable to keep locking time short */
		{
			volatile pgssEntry *e = (volatile pgssEntry *) entry;

			SpinLockAcquire(&e->mutex);
			tmp = e->counters;
			SpinLockRelease(&e->mutex);
		}

		values[i++] = Int64GetDatumFast(tmp.calls);
		values[i++] = Float8GetDatumFast(tmp.total_time);
		values[i++] = Int64GetDatumFast(tmp.rows);
		values[i++] = Int64GetDatumFast(tmp.shared_blks_hit);
		values[i++] = Int64GetDatumFast(tmp.shared_blks_read);
		values[i++] = Int64GetDatumFast(tmp.shared_blks_written);
		values[i++] = Int64GetDatumFast(tmp.local_blks_hit);
		values[i++] = Int64GetDatumFast(tmp.local_blks_read);
		values[i++] = Int64GetDatumFast(tmp.local_blks_written);
		values[i++] = Int64GetDatumFast(tmp.temp_blks_read);
		values[i++] = Int64GetDatumFast(tmp.temp_blks_written);

		Assert(i == PG_STAT_STATEMENTS_COLS);
//.........这里部分代码省略.........

/*
 * pg_stop_backup_v2: finish taking exclusive or nonexclusive on-line backup.
 *
 * Works the same as pg_stop_backup, except for non-exclusive backups it returns
 * the backup label and tablespace map files as text fields in as part of the
 * resultset.
 *
 * Permission checking for this function is managed through the normal
 * GRANT system.
 */
Datum
pg_stop_backup_v2(PG_FUNCTION_ARGS)
{
	ReturnSetInfo  *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
	TupleDesc		tupdesc;
	Tuplestorestate *tupstore;
	MemoryContext	per_query_ctx;
	MemoryContext	oldcontext;
	Datum			values[3];
	bool			nulls[3];

	bool			exclusive = PG_GETARG_BOOL(0);
	XLogRecPtr		stoppoint;

	/* check to see if caller supports us returning a tuplestore */
	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("set-valued function called in context that cannot accept a set")));
	if (!(rsinfo->allowedModes & SFRM_Materialize))
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("materialize mode required, but it is not " \
						"allowed in this context")));

	/* Build a tuple descriptor for our result type */
	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
		elog(ERROR, "return type must be a row type");

	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
	oldcontext = MemoryContextSwitchTo(per_query_ctx);

	tupstore = tuplestore_begin_heap(true, false, work_mem);
	rsinfo->returnMode = SFRM_Materialize;
	rsinfo->setResult = tupstore;
	rsinfo->setDesc = tupdesc;

	MemoryContextSwitchTo(oldcontext);

	MemSet(values, 0, sizeof(values));
	MemSet(nulls, 0, sizeof(nulls));

	if (exclusive)
	{
		if (nonexclusive_backup_running)
			ereport(ERROR,
					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
					 errmsg("non-exclusive backup in progress"),
					 errhint("Did you mean to use pg_stop_backup('f')?")));

		/*
		 * Stop the exclusive backup, and since we're in an exclusive backup
		 * return NULL for both backup_label and tablespace_map.
		 */
		stoppoint = do_pg_stop_backup(NULL, true, NULL);
		exclusive_backup_running = false;

		nulls[1] = true;
		nulls[2] = true;
	}
	else
	{
		if (!nonexclusive_backup_running)
			ereport(ERROR,
					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
					 errmsg("non-exclusive backup is not in progress"),
					 errhint("Did you mean to use pg_stop_backup('t')?")));

		/*
		 * Stop the non-exclusive backup. Return a copy of the backup
		 * label and tablespace map so they can be written to disk by
		 * the caller.
		 */
		stoppoint = do_pg_stop_backup(label_file->data, true, NULL);
		nonexclusive_backup_running = false;
		cancel_before_shmem_exit(nonexclusive_base_backup_cleanup, (Datum) 0);

		values[1] = CStringGetTextDatum(label_file->data);
		values[2] = CStringGetTextDatum(tblspc_map_file->data);

		/* Free structures allocated in TopMemoryContext */
		pfree(label_file->data);
		pfree(label_file);
		label_file = NULL;
		pfree(tblspc_map_file->data);
		pfree(tblspc_map_file);
		tblspc_map_file = NULL;
	}

	/* Stoppoint is included on both exclusive and nonexclusive backups */
//.........这里部分代码省略.........

/*
 * _outNode -
 *	  converts a Node into binary string and append it to 'str'
 */
static void
_outNode(StringInfo str, void *obj)
{
	if (obj == NULL)
	{
		int16 tg = 0;
		appendBinaryStringInfo(str, (const char *)&tg, sizeof(int16));
	}
	else if (IsA(obj, List) ||IsA(obj, IntList) || IsA(obj, OidList))
		_outList(str, obj);
	else if (IsA(obj, Integer) ||
			 IsA(obj, Float) ||
			 IsA(obj, String) ||
			 IsA(obj, Null) ||
			 IsA(obj, BitString))
	{
		_outValue(str, obj);
	}
	else
	{
		switch (nodeTag(obj))
		{
			case T_PlannedStmt:
				_outPlannedStmt(str,obj);
				break;
			case T_QueryDispatchDesc:
				_outQueryDispatchDesc(str,obj);
				break;
			case T_OidAssignment:
				_outOidAssignment(str,obj);
				break;
			case T_Plan:
				_outPlan(str, obj);
				break;
			case T_Result:
				_outResult(str, obj);
				break;
			case T_Repeat:
				_outRepeat(str, obj);
				break;
			case T_Append:
				_outAppend(str, obj);
				break;
			case T_Sequence:
				_outSequence(str, obj);
				break;
			case T_BitmapAnd:
				_outBitmapAnd(str, obj);
				break;
			case T_BitmapOr:
				_outBitmapOr(str, obj);
				break;
			case T_Scan:
				_outScan(str, obj);
				break;
			case T_SeqScan:
				_outSeqScan(str, obj);
				break;
			case T_AppendOnlyScan:
				_outAppendOnlyScan(str, obj);
				break;
			case T_AOCSScan:
				_outAOCSScan(str, obj);
				break;
			case T_TableScan:
				_outTableScan(str, obj);
				break;
			case T_DynamicTableScan:
				_outDynamicTableScan(str, obj);
				break;
			case T_ExternalScan:
				_outExternalScan(str, obj);
				break;
			case T_IndexScan:
				_outIndexScan(str, obj);
				break;
			case T_DynamicIndexScan:
				_outDynamicIndexScan(str, obj);
				break;
			case T_BitmapIndexScan:
				_outBitmapIndexScan(str, obj);
				break;
			case T_BitmapHeapScan:
				_outBitmapHeapScan(str, obj);
				break;
			case T_BitmapAppendOnlyScan:
				_outBitmapAppendOnlyScan(str, obj);
				break;
			case T_BitmapTableScan:
				_outBitmapTableScan(str, obj);
				break;
			case T_TidScan:
				_outTidScan(str, obj);
				break;
			case T_SubqueryScan:
				_outSubqueryScan(str, obj);
//.........这里部分代码省略.........

/*
 * Generate targetlist for a set-operation plan node
 *
 * colTypes: column datatypes for non-junk columns
 * flag: -1 if no flag column needed, 0 or 1 to create a const flag column
 * hack_constants: true to copy up constants (see comments in code)
 * input_tlist: targetlist of this node's input node
 * refnames_tlist: targetlist to take column names from
 */
static List *
generate_setop_tlist(List *colTypes, int flag,
                     bool hack_constants,
                     List *input_tlist,
                     List *refnames_tlist)
{
    List	   *tlist = NIL;
    int			resno = 1;
    List	   *i;
    Resdom	   *resdom;
    Node	   *expr;

    foreach(i, colTypes)
    {
        Oid			colType = lfirsto(i);
        TargetEntry *inputtle = (TargetEntry *) lfirst(input_tlist);
        TargetEntry *reftle = (TargetEntry *) lfirst(refnames_tlist);
        int32		colTypmod;

        Assert(inputtle->resdom->resno == resno);
        Assert(reftle->resdom->resno == resno);
        Assert(!inputtle->resdom->resjunk);
        Assert(!reftle->resdom->resjunk);

        /*
         * Generate columns referencing input columns and having
         * appropriate data types and column names.  Insert datatype
         * coercions where necessary.
         *
         * HACK: constants in the input's targetlist are copied up as-is
         * rather than being referenced as subquery outputs.  This is
         * mainly to ensure that when we try to coerce them to the output
         * column's datatype, the right things happen for UNKNOWN
         * constants.  But do this only at the first level of
         * subquery-scan plans; we don't want phony constants appearing in
         * the output tlists of upper-level nodes!
         */
        if (hack_constants && inputtle->expr && IsA(inputtle->expr, Const))
            expr = (Node *) inputtle->expr;
        else
            expr = (Node *) makeVar(0,
                                    inputtle->resdom->resno,
                                    inputtle->resdom->restype,
                                    inputtle->resdom->restypmod,
                                    0);
        if (inputtle->resdom->restype == colType)
        {
            /* no coercion needed, and believe the input typmod */
            colTypmod = inputtle->resdom->restypmod;
        }
        else
        {
            expr = coerce_to_common_type(NULL,	/* no UNKNOWNs here */
                                         expr,
                                         colType,
                                         "UNION/INTERSECT/EXCEPT");
            colTypmod = -1;
        }
        resdom = makeResdom((AttrNumber) resno++,
                            colType,
                            colTypmod,
                            pstrdup(reftle->resdom->resname),
                            false);
        tlist = lappend(tlist, makeTargetEntry(resdom, (Expr *) expr));
        input_tlist = lnext(input_tlist);
        refnames_tlist = lnext(refnames_tlist);
    }