lsyscache.c

							  typbyval,
							  typalign,
							  typdelim,
							  typioparam,
							  &typinput,
							  &typoutput);
		switch (which_func)
		{
			case IOFunc_input:
				*func = typinput;
				break;
			case IOFunc_output:
				*func = typoutput;
				break;
			default:
				elog(ERROR, "binary I/O not supported during bootstrap");
				break;
		}
		return;
	}

	typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
	if (!HeapTupleIsValid(typeTuple))
		elog(ERROR, "cache lookup failed for type %u", typid);
	typeStruct = (Form_pg_type) GETSTRUCT(typeTuple);

	*typlen = typeStruct->typlen;
	*typbyval = typeStruct->typbyval;
	*typalign = typeStruct->typalign;
	*typdelim = typeStruct->typdelim;
	*typioparam = getTypeIOParam(typeTuple);
	switch (which_func)
	{
		case IOFunc_input:
			*func = typeStruct->typinput;
			break;
		case IOFunc_output:
			*func = typeStruct->typoutput;
			break;
		case IOFunc_receive:
			*func = typeStruct->typreceive;
			break;
		case IOFunc_send:
			*func = typeStruct->typsend;
			break;
	}
	ReleaseSysCache(typeTuple);
}

#ifdef NOT_USED
char
get_typalign(Oid typid)
{
	HeapTuple	tp;

	tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
	if (HeapTupleIsValid(tp))
	{
		Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
		char		result;

		result = typtup->typalign;
		ReleaseSysCache(tp);
		return result;
	}
	else
		return 'i';
}
#endif

char
get_typstorage(Oid typid)
{
	HeapTuple	tp;

	tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
	if (HeapTupleIsValid(tp))
	{
		Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
		char		result;

		result = typtup->typstorage;
		ReleaseSysCache(tp);
		return result;
	}
	else
		return 'p';
}

/*
 * get_typdefault
 *	  Given a type OID, return the type's default value, if any.
 *
 *	  The result is a palloc'd expression node tree, or NULL if there
 *	  is no defined default for the datatype.
 *
 * NB: caller should be prepared to coerce result to correct datatype;
 * the returned expression tree might produce something of the wrong type.
 */
Node *
get_typdefault(Oid typid)
{
	HeapTuple	typeTuple;
	Form_pg_type type;
	Datum		datum;
	bool		isNull;
	Node	   *expr;

	typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
	if (!HeapTupleIsValid(typeTuple))
		elog(ERROR, "cache lookup failed for type %u", typid);
	type = (Form_pg_type) GETSTRUCT(typeTuple);

	/*
	 * typdefault and typdefaultbin are potentially null, so don't try to
	 * access 'em as struct fields. Must do it the hard way with
	 * SysCacheGetAttr.
	 */
	datum = SysCacheGetAttr(TYPEOID,
							typeTuple,
							Anum_pg_type_typdefaultbin,
							&isNull);

	if (!isNull)
	{
		/* We have an expression default */
		expr = stringToNode(TextDatumGetCString(datum));
	}
	else
	{
		/* Perhaps we have a plain literal default */
		datum = SysCacheGetAttr(TYPEOID,
								typeTuple,
								Anum_pg_type_typdefault,
								&isNull);

		if (!isNull)
		{
			char	   *strDefaultVal;

			/* Convert text datum to C string */
			strDefaultVal = TextDatumGetCString(datum);
			/* Convert C string to a value of the given type */
			datum = OidInputFunctionCall(type->typinput, strDefaultVal,
										 getTypeIOParam(typeTuple), -1);
			/* Build a Const node containing the value */
			expr = (Node *) makeConst(typid,
									  -1,
									  type->typcollation,
									  type->typlen,
									  datum,
									  false,
									  type->typbyval);
			pfree(strDefaultVal);
		}
		else
		{
			/* No default */
			expr = NULL;
		}
	}

	ReleaseSysCache(typeTuple);

	return expr;
}

/*
 * getBaseType
 *		If the given type is a domain, return its base type;
 *		otherwise return the type's own OID.
 */
Oid
getBaseType(Oid typid)
{
	int32		typmod = -1;

	return getBaseTypeAndTypmod(typid, &typmod);
}

/*
 * getBaseTypeAndTypmod
 *		If the given type is a domain, return its base type and typmod;
 *		otherwise return the type's own OID, and leave *typmod unchanged.
 *
 * Note that the "applied typmod" should be -1 for every domain level
 * above the bottommost; therefore, if the passed-in typid is indeed
 * a domain, *typmod should be -1.
 */
Oid
getBaseTypeAndTypmod(Oid typid, int32 *typmod)
{
	/*
	 * We loop to find the bottom base type in a stack of domains.
	 */
	for (;;)
	{
		HeapTuple	tup;
		Form_pg_type typTup;

		tup = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
		if (!HeapTupleIsValid(tup))
			elog(ERROR, "cache lookup failed for type %u", typid);
		typTup = (Form_pg_type) GETSTRUCT(tup);
		if (typTup->typtype != TYPTYPE_DOMAIN)
		{
			/* Not a domain, so done */
			ReleaseSysCache(tup);
			break;
		}

		Assert(*typmod == -1);
		typid = typTup->typbasetype;
		*typmod = typTup->typtypmod;

		ReleaseSysCache(tup);
	}

	return typid;
}

/*
 * get_typavgwidth
 *
 *	  Given a type OID and a typmod value (pass -1 if typmod is unknown),
 *	  estimate the average width of values of the type.  This is used by
 *	  the planner, which doesn't require absolutely correct results;
 *	  it's OK (and expected) to guess if we don't know for sure.
 */
int32
get_typavgwidth(Oid typid, int32 typmod)
{
	int			typlen = get_typlen(typid);
	int32		maxwidth;

	/*
	 * Easy if it's a fixed-width type
	 */
	if (typlen > 0)
		return typlen;

	/*
	 * type_maximum_size knows the encoding of typmod for some datatypes;
	 * don't duplicate that knowledge here.
	 */
	maxwidth = type_maximum_size(typid, typmod);
	if (maxwidth > 0)
	{
		/*
		 * For BPCHAR, the max width is also the only width.  Otherwise we
		 * need to guess about the typical data width given the max. A sliding
		 * scale for percentage of max width seems reasonable.
		 */
		if (typid == BPCHAROID)
			return maxwidth;
		if (maxwidth <= 32)
			return maxwidth;	/* assume full width */
		if (maxwidth < 1000)
			return 32 + (maxwidth - 32) / 2;	/* assume 50% */

		/*
		 * Beyond 1000, assume we're looking at something like
		 * "varchar(10000)" where the limit isn't actually reached often, and
		 * use a fixed estimate.
		 */
		return 32 + (1000 - 32) / 2;
	}

	/*
	 * Ooops, we have no idea ... wild guess time.
	 */
	return 32;
}

/*
 * get_typtype
 *
 *		Given the type OID, find if it is a basic type, a complex type, etc.
 *		It returns the null char if the cache lookup fails...
 */
char
get_typtype(Oid typid)
{
	HeapTuple	tp;

	tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
	if (HeapTupleIsValid(tp))
	{
		Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
		char		result;

		result = typtup->typtype;
		ReleaseSysCache(tp);
		return result;
	}
	else
		return '\0';
}

/*
 * type_is_rowtype
 *
 *		Convenience function to determine whether a type OID represents
 *		a "rowtype" type --- either RECORD or a named composite type.
 */
bool
type_is_rowtype(Oid typid)
{
	return (typid == RECORDOID || get_typtype(typid) == TYPTYPE_COMPOSITE);
}

/*
 * type_is_enum
 *	  Returns true if the given type is an enum type.
 */
bool
type_is_enum(Oid typid)
{
	return (get_typtype(typid) == TYPTYPE_ENUM);
}

/*
 * type_is_range
 *	  Returns true if the given type is a range type.
 */
bool
type_is_range(Oid typid)
{
	return (get_typtype(typid) == TYPTYPE_RANGE);
}

/*
 * get_type_category_preferred
 *
 *		Given the type OID, fetch its category and preferred-type status.
 *		Throws error on failure.
 */
void
get_type_category_preferred(Oid typid, char *typcategory, bool *typispreferred)
{
	HeapTuple	tp;
	Form_pg_type typtup;

	tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
	if (!HeapTupleIsValid(tp))
		elog(ERROR, "cache lookup failed for type %u", typid);
	typtup = (Form_pg_type) GETSTRUCT(tp);
	*typcategory = typtup->typcategory;
	*typispreferred = typtup->typispreferred;
	ReleaseSysCache(tp);
}

/*
 * get_typ_typrelid
 *
 *		Given the type OID, get the typrelid (InvalidOid if not a complex
 *		type).
 */
Oid
get_typ_typrelid(Oid typid)
{
	HeapTuple	tp;

	tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
	if (HeapTupleIsValid(tp))
	{
		Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
		Oid			result;

		result = typtup->typrelid;
		ReleaseSysCache(tp);
		return result;
	}
	else
		return InvalidOid;
}

/*
 * get_element_type
 *
 *		Given the type OID, get the typelem (InvalidOid if not an array type).
 *
 * NB: this only considers varlena arrays to be true arrays; InvalidOid is
 * returned if the input is a fixed-length array type.
 */
Oid
get_element_type(Oid typid)
{
	HeapTuple	tp;

	tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
	if (HeapTupleIsValid(tp))
	{
		Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
		Oid			result;

		if (typtup->typlen == -1)
			result = typtup->typelem;
		else
			result = InvalidOid;
		ReleaseSysCache(tp);
		return result;
	}
	else
		return InvalidOid;
}

/*
 * get_array_type
 *
 *		Given the type OID, get the corresponding "true" array type.
 *		Returns InvalidOid if no array type can be found.
 */
Oid
get_array_type(Oid typid)
{
	HeapTuple	tp;
	Oid			result = InvalidOid;

	tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
	if (HeapTupleIsValid(tp))
	{
		result = ((Form_pg_type) GETSTRUCT(tp))->typarray;
		ReleaseSysCache(tp);
	}
	return result;
}

/*
 * get_promoted_array_type
 *
 *		The "promoted" type is what you'd get from an ARRAY(SELECT ...)
 *		construct, that is, either the corresponding "true" array type
 *		if the input is a scalar type that has such an array type,
 *		or the same type if the input is already a "true" array type.
 *		Returns InvalidOid if neither rule is satisfied.
 */
Oid
get_promoted_array_type(Oid typid)
{
	Oid			array_type = get_array_type(typid);

	if (OidIsValid(array_type))
		return array_type;
	if (OidIsValid(get_element_type(typid)))
		return typid;
	return InvalidOid;
}

/*
 * get_base_element_type
 *		Given the type OID, get the typelem, looking "through" any domain
 *		to its underlying array type.
 *
 * This is equivalent to get_element_type(getBaseType(typid)), but avoids
 * an extra cache lookup.  Note that it fails to provide any information
 * about the typmod of the array.
 */
Oid
get_base_element_type(Oid typid)
{
	/*
	 * We loop to find the bottom base type in a stack of domains.
	 */
	for (;;)
	{
		HeapTuple	tup;
		Form_pg_type typTup;

		tup = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
		if (!HeapTupleIsValid(tup))
			break;
		typTup = (Form_pg_type) GETSTRUCT(tup);
		if (typTup->typtype != TYPTYPE_DOMAIN)
		{
			/* Not a domain, so stop descending */
			Oid			result;

			/* This test must match get_element_type */
			if (typTup->typlen == -1)
				result = typTup->typelem;
			else
				result = InvalidOid;
			ReleaseSysCache(tup);
			return result;
		}

		typid = typTup->typbasetype;
		ReleaseSysCache(tup);
	}

	/* Like get_element_type, silently return InvalidOid for bogus input */
	return InvalidOid;
}

/*
 * getTypeInputInfo
 *
 *		Get info needed for converting values of a type to internal form
 */
void
getTypeInputInfo(Oid type, Oid *typInput, Oid *typIOParam)
{
	HeapTuple	typeTuple;
	Form_pg_type pt;

	typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(type));
	if (!HeapTupleIsValid(typeTuple))
		elog(ERROR, "cache lookup failed for type %u", type);
	pt = (Form_pg_type) GETSTRUCT(typeTuple);

	if (!pt->typisdefined)
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("type %s is only a shell",
						format_type_be(type))));
	if (!OidIsValid(pt->typinput))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_FUNCTION),
				 errmsg("no input function available for type %s",
						format_type_be(type))));

	*typInput = pt->typinput;
	*typIOParam = getTypeIOParam(typeTuple);

	ReleaseSysCache(typeTuple);
}

/*
 * getTypeOutputInfo
 *
 *		Get info needed for printing values of a type
 */
void
getTypeOutputInfo(Oid type, Oid *typOutput, bool *typIsVarlena)
{
	HeapTuple	typeTuple;
	Form_pg_type pt;

	typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(type));
	if (!HeapTupleIsValid(typeTuple))
		elog(ERROR, "cache lookup failed for type %u", type);
	pt = (Form_pg_type) GETSTRUCT(typeTuple);

	if (!pt->typisdefined)
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("type %s is only a shell",
						format_type_be(type))));
	if (!OidIsValid(pt->typoutput))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_FUNCTION),
				 errmsg("no output function available for type %s",
						format_type_be(type))));

	*typOutput = pt->typoutput;
	*typIsVarlena = (!pt->typbyval) && (pt->typlen == -1);

	ReleaseSysCache(typeTuple);
}

/*
 * getTypeBinaryInputInfo
 *
 *		Get info needed for binary input of values of a type
 */
void
getTypeBinaryInputInfo(Oid type, Oid *typReceive, Oid *typIOParam)
{
	HeapTuple	typeTuple;
	Form_pg_type pt;

	typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(type));
	if (!HeapTupleIsValid(typeTuple))
		elog(ERROR, "cache lookup failed for type %u", type);
	pt = (Form_pg_type) GETSTRUCT(typeTuple);

	if (!pt->typisdefined)
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("type %s is only a shell",
						format_type_be(type))));
	if (!OidIsValid(pt->typreceive))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_FUNCTION),
				 errmsg("no binary input function available for type %s",
						format_type_be(type))));

	*typReceive = pt->typreceive;
	*typIOParam = getTypeIOParam(typeTuple);

	ReleaseSysCache(typeTuple);
}

/*
 * getTypeBinaryOutputInfo
 *
 *		Get info needed for binary output of values of a type
 */
void
getTypeBinaryOutputInfo(Oid type, Oid *typSend, bool *typIsVarlena)
{
	HeapTuple	typeTuple;
	Form_pg_type pt;

	typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(type));
	if (!HeapTupleIsValid(typeTuple))
		elog(ERROR, "cache lookup failed for type %u", type);
	pt = (Form_pg_type) GETSTRUCT(typeTuple);

	if (!pt->typisdefined)
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_OBJECT),
				 errmsg("type %s is only a shell",
						format_type_be(type))));
	if (!OidIsValid(pt->typsend))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_FUNCTION),
				 errmsg("no binary output function available for type %s",
						format_type_be(type))));

	*typSend = pt->typsend;
	*typIsVarlena = (!pt->typbyval) && (pt->typlen == -1);

	ReleaseSysCache(typeTuple);
}

/*
 * get_typmodin
 *
 *		Given the type OID, return the type's typmodin procedure, if any.
 */
Oid
get_typmodin(Oid typid)
{
	HeapTuple	tp;

	tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
	if (HeapTupleIsValid(tp))
	{
		Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
		Oid			result;

		result = typtup->typmodin;
		ReleaseSysCache(tp);
		return result;
	}
	else
		return InvalidOid;
}

#ifdef NOT_USED
/*
 * get_typmodout
 *
 *		Given the type OID, return the type's typmodout procedure, if any.
 */
Oid
get_typmodout(Oid typid)
{
	HeapTuple	tp;

	tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
	if (HeapTupleIsValid(tp))
	{
		Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
		Oid			result;

		result = typtup->typmodout;
		ReleaseSysCache(tp);
		return result;
	}
	else
		return InvalidOid;
}
#endif   /* NOT_USED */

/*
 * get_typcollation
 *
 *		Given the type OID, return the type's typcollation attribute.
 */
Oid
get_typcollation(Oid typid)
{
	HeapTuple	tp;

	tp = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
	if (HeapTupleIsValid(tp))
	{
		Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
		Oid			result;

		result = typtup->typcollation;
		ReleaseSysCache(tp);
		return result;
	}
	else
		return InvalidOid;
}


/*
 * type_is_collatable
 *
 *		Return whether the type cares about collations
 */
bool
type_is_collatable(Oid typid)
{
	return OidIsValid(get_typcollation(typid));
}


/*				---------- STATISTICS CACHE ----------					 */

/*
 * get_attavgwidth
 *
 *	  Given the table and attribute number of a column, get the average
 *	  width of entries in the column.  Return zero if no data available.
 *
 * Currently this is only consulted for individual tables, not for inheritance
 * trees, so we don't need an "inh" parameter.
 *
 * Calling a hook at this point looks somewhat strange, but is required
 * because the optimizer calls this function without any other way for
 * plug-ins to control the result.
 */
int32
get_attavgwidth(Oid relid, AttrNumber attnum)
{
	HeapTuple	tp;
	int32		stawidth;

	if (get_attavgwidth_hook)
	{
		stawidth = (*get_attavgwidth_hook) (relid, attnum);
		if (stawidth > 0)
			return stawidth;
	}
	tp = SearchSysCache3(STATRELATTINH,
						 ObjectIdGetDatum(relid),
						 Int16GetDatum(attnum),
						 BoolGetDatum(false));
	if (HeapTupleIsValid(tp))
	{
		stawidth = ((Form_pg_statistic) GETSTRUCT(tp))->stawidth;
		ReleaseSysCache(tp);
		if (stawidth > 0)
			return stawidth;
	}
	return 0;
}

/*
 * get_attstatsslot
 *
 *		Extract the contents of a "slot" of a pg_statistic tuple.
 *		Returns TRUE if requested slot type was found, else FALSE.
 *
 * Unlike other routines in this file, this takes a pointer to an
 * already-looked-up tuple in the pg_statistic cache.  We do this since
 * most callers will want to extract more than one value from the cache
 * entry, and we don't want to repeat the cache lookup unnecessarily.
 * Also, this API allows this routine to be used with statistics tuples
 * that have been provided by a stats hook and didn't really come from
 * pg_statistic.
 *
 * statstuple: pg_statistic tuple to be examined.
 * atttype: type OID of slot's stavalues (can be InvalidOid if values == NULL).
 * atttypmod: typmod of slot's stavalues (can be 0 if values == NULL).
 * reqkind: STAKIND code for desired statistics slot kind.
 * reqop: STAOP value wanted, or InvalidOid if don't care.
 * actualop: if not NULL, *actualop receives the actual STAOP value.
 * values, nvalues: if not NULL, the slot's stavalues are extracted.
 * numbers, nnumbers: if not NULL, the slot's stanumbers are extracted.
 *
 * If assigned, values and numbers are set to point to palloc'd arrays.
 * If the stavalues datatype is pass-by-reference, the values referenced by
 * the values array are themselves palloc'd.  The palloc'd stuff can be
 * freed by calling free_attstatsslot.
 *
 * Note: at present, atttype/atttypmod aren't actually used here at all.
 * But the caller must have the correct (or at least binary-compatible)
 * type ID to pass to free_attstatsslot later.
 */
bool
get_attstatsslot(HeapTuple statstuple,
				 Oid atttype, int32 atttypmod,
				 int reqkind, Oid reqop,
				 Oid *actualop,
				 Datum **values, int *nvalues,
				 float4 **numbers, int *nnumbers)
{
	Form_pg_statistic stats = (Form_pg_statistic) GETSTRUCT(statstuple);
	int			i,
				j;
	Datum		val;
	bool		isnull;
	ArrayType  *statarray;
	Oid			arrayelemtype;
	int			narrayelem;
	HeapTuple	typeTuple;
	Form_pg_type typeForm;

	for (i = 0; i < STATISTIC_NUM_SLOTS; i++)
	{
		if ((&stats->stakind1)[i] == reqkind &&
			(reqop == InvalidOid || (&stats->staop1)[i] == reqop))
			break;
	}
	if (i >= STATISTIC_NUM_SLOTS)
		return false;			/* not there */

	if (actualop)
		*actualop = (&stats->staop1)[i];

	if (values)
	{
		val = SysCacheGetAttr(STATRELATTINH, statstuple,
							  Anum_pg_statistic_stavalues1 + i,
							  &isnull);
		if (isnull)
			elog(ERROR, "stavalues is null");
		statarray = DatumGetArrayTypeP(val);

		/*
		 * Need to get info about the array element type.  We look at the
		 * actual element type embedded in the array, which might be only
		 * binary-compatible with the passed-in atttype.  The info we extract
		 * here should be the same either way, but deconstruct_array is picky
		 * about having an exact type OID match.
		 */
		arrayelemtype = ARR_ELEMTYPE(statarray);
		typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(arrayelemtype));
		if (!HeapTupleIsValid(typeTuple))
			elog(ERROR, "cache lookup failed for type %u", arrayelemtype);
		typeForm = (Form_pg_type) GETSTRUCT(typeTuple);

		/* Deconstruct array into Datum elements; NULLs not expected */
		deconstruct_array(statarray,
						  arrayelemtype,
						  typeForm->typlen,
						  typeForm->typbyval,
						  typeForm->typalign,
						  values, NULL, nvalues);

		/*
		 * If the element type is pass-by-reference, we now have a bunch of
		 * Datums that are pointers into the syscache value.  Copy them to
		 * avoid problems if syscache decides to drop the entry.
		 */
		if (!typeForm->typbyval)
		{
			for (j = 0; j < *nvalues; j++)
			{
				(*values)[j] = datumCopy((*values)[j],
										 typeForm->typbyval,
										 typeForm->typlen);
			}
		}

		ReleaseSysCache(typeTuple);

		/*
		 * Free statarray if it's a detoasted copy.
		 */
		if ((Pointer) statarray != DatumGetPointer(val))
			pfree(statarray);
	}

	if (numbers)
	{
		val = SysCacheGetAttr(STATRELATTINH, statstuple,
							  Anum_pg_statistic_stanumbers1 + i,
							  &isnull);
		if (isnull)
			elog(ERROR, "stanumbers is null");
		statarray = DatumGetArrayTypeP(val);

		/*
		 * We expect the array to be a 1-D float4 array; verify that. We don't
		 * need to use deconstruct_array() since the array data is just going
		 * to look like a C array of float4 values.
		 */
		narrayelem = ARR_DIMS(statarray)[0];
		if (ARR_NDIM(statarray) != 1 || narrayelem <= 0 ||
			ARR_HASNULL(statarray) ||
			ARR_ELEMTYPE(statarray) != FLOAT4OID)
			elog(ERROR, "stanumbers is not a 1-D float4 array");
		*numbers = (float4 *) palloc(narrayelem * sizeof(float4));
		memcpy(*numbers, ARR_DATA_PTR(statarray), narrayelem * sizeof(float4));
		*nnumbers = narrayelem;

		/*
		 * Free statarray if it's a detoasted copy.
		 */
		if ((Pointer) statarray != DatumGetPointer(val))
			pfree(statarray);
	}

	return true;
}

/*
 * free_attstatsslot
 *		Free data allocated by get_attstatsslot
 *
 * atttype is the type of the individual values in values[].
 * It need be valid only if values != NULL.
 */
void
free_attstatsslot(Oid atttype,
				  Datum *values, int nvalues,
				  float4 *numbers, int nnumbers)
{
	if (values)
	{
		if (!get_typbyval(atttype))
		{
			int			i;

			for (i = 0; i < nvalues; i++)
				pfree(DatumGetPointer(values[i]));
		}
		pfree(values);
	}
	if (numbers)
		pfree(numbers);
}

/*				---------- PG_NAMESPACE CACHE ----------				 */

/*
 * get_namespace_name
 *		Returns the name of a given namespace
 *
 * Returns a palloc'd copy of the string, or NULL if no such namespace.
 */
char *
get_namespace_name(Oid nspid)
{
	HeapTuple	tp;

	tp = SearchSysCache1(NAMESPACEOID, ObjectIdGetDatum(nspid));
	if (HeapTupleIsValid(tp))
	{
		Form_pg_namespace nsptup = (Form_pg_namespace) GETSTRUCT(tp);
		char	   *result;

		result = pstrdup(NameStr(nsptup->nspname));
		ReleaseSysCache(tp);
		return result;
	}
	else
		return NULL;
}

/*
 * get_namespace_name_or_temp
 *		As above, but if it is this backend's temporary namespace, return
 *		"pg_temp" instead.
 */
char *
get_namespace_name_or_temp(Oid nspid)
{
	if (isTempNamespace(nspid))
		return "pg_temp";
	else
		return get_namespace_name(nspid);
}

/*				---------- PG_RANGE CACHE ----------				 */

/*
 * get_range_subtype
 *		Returns the subtype of a given range type
 *
 * Returns InvalidOid if the type is not a range type.
 */
Oid
get_range_subtype(Oid rangeOid)
{
	HeapTuple	tp;

	tp = SearchSysCache1(RANGETYPE, ObjectIdGetDatum(rangeOid));
	if (HeapTupleIsValid(tp))
	{
		Form_pg_range rngtup = (Form_pg_range) GETSTRUCT(tp);
		Oid			result;

		result = rngtup->rngsubtype;
		ReleaseSysCache(tp);
		return result;
	}
	else
		return InvalidOid;
}