Re: SQL:2011 application time

in GetOperatorFromWellKnownStrategy:
*strat = GistTranslateStratnum(opclass, instrat);
if (*strat == InvalidStrategy)
{
HeapTuple tuple;
tuple = SearchSysCache1(CLAOID, ObjectIdGetDatum(opclass));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for operator class %u", opclass);
ereport(ERROR,
errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg(errstr, format_type_be(opcintype)),
errdetail("Could not translate strategy number %d for operator class
\"%s\" for access method \"%s\".",
instrat, NameStr(((Form_pg_opclass) GETSTRUCT(tuple))->opcname), "gist"));
ReleaseSysCache(tuple);
}

last `ReleaseSysCache(tuple);` is unreachable?

@@ -118,12 +120,17 @@ typedef struct RI_ConstraintInfo
int16 confdelsetcols[RI_MAX_NUMKEYS]; /* attnums of cols to set on
* delete */
char confmatchtype; /* foreign key's match type */
+ bool temporal; /* if the foreign key is temporal */
int nkeys; /* number of key columns */
int16 pk_attnums[RI_MAX_NUMKEYS]; /* attnums of referenced cols */
int16 fk_attnums[RI_MAX_NUMKEYS]; /* attnums of referencing cols */
Oid pf_eq_oprs[RI_MAX_NUMKEYS]; /* equality operators (PK = FK) */
Oid pp_eq_oprs[RI_MAX_NUMKEYS]; /* equality operators (PK = PK) */
Oid ff_eq_oprs[RI_MAX_NUMKEYS]; /* equality operators (FK = FK) */
+ Oid period_contained_by_oper; /* operator for PERIOD SQL */
+ Oid agged_period_contained_by_oper; /* operator for PERIOD SQL */
+ Oid period_referenced_agg_proc; /* proc for PERIOD SQL */
+ Oid period_referenced_agg_rettype; /* rettype for previous */

the comment seems not clear to me. Here is my understanding about it:
period_contained_by_oper is the operator where a single period/range
contained by a single period/range.
agged_period_contained_by_oper is the operator oid where a period
contained by a bound of periods
period_referenced_agg_proc is the oprcode of the agged_period_contained_by_oper.
period_referenced_agg_rettype is the function
period_referenced_agg_proc returning data type.