Remove GetUserMappingId() and GetUserMappingById().

These functions were added in commits fbe5a3fb7 and a104a017f,
but commit 45639a052 removed their only callers.  Put the related
code in foreign.c back to the way it was in 9.5, to avoid pointless
cross-version diffs.

Etsuro Fujita

Patch: <d674a3f1-6b63-519c-ef3f-f3188ed6a178@lab.ntt.co.jp>

doc/src/sgml/fdwhandler.sgml

@@ -1323,20 +1323,6 @@ GetForeignTable(Oid relid);
 
     <para>
 <programlisting>
-UserMapping *
-GetUserMappingById(Oid umid);
-</programlisting>
-
-     This function returns the <structname>UserMapping</structname> object for
-     the given user mapping OID.  The OID of a user mapping for a foreign scan
-     is available in the <structname>RelOptInfo</structname>.
-     If there is no mapping for the OID, this function will throw an error.
-     A <structname>UserMapping</structname> object contains properties of the
-     user mapping (see <filename>foreign/foreign.h</filename> for details).
-    </para>
-
-    <para>
-<programlisting>
 List *
 GetForeignColumnOptions(Oid relid, AttrNumber attnum);
 </programlisting>

src/backend/foreign/foreign.c

@@ -31,8 +31,6 @@
 extern Datum pg_options_to_table(PG_FUNCTION_ARGS);
 extern Datum postgresql_fdw_validator(PG_FUNCTION_ARGS);
 
-static HeapTuple find_user_mapping(Oid userid, Oid serverid);
-
 
 /*
  * GetForeignDataWrapper -	look up the foreign-data wrapper by OID.
@@ -161,54 +159,6 @@ GetForeignServerByName(const char *srvname, bool missing_ok)
 	return GetForeignServer(serverid);
 }
 
-/*
- * GetUserMappingById - look up the user mapping by its OID.
- */
-UserMapping *
-GetUserMappingById(Oid umid)
-{
-	Datum		datum;
-	HeapTuple	tp;
-	bool		isnull;
-	UserMapping *um;
-
-	tp = SearchSysCache1(USERMAPPINGOID, ObjectIdGetDatum(umid));
-	if (!HeapTupleIsValid(tp))
-		elog(ERROR, "cache lookup failed for user mapping %u", umid);
-
-	um = (UserMapping *) palloc(sizeof(UserMapping));
-	um->umid = umid;
-
-	/* Extract the umuser */
-	datum = SysCacheGetAttr(USERMAPPINGOID,
-							tp,
-							Anum_pg_user_mapping_umuser,
-							&isnull);
-	Assert(!isnull);
-	um->userid = DatumGetObjectId(datum);
-
-	/* Extract the umserver */
-	datum = SysCacheGetAttr(USERMAPPINGOID,
-							tp,
-							Anum_pg_user_mapping_umserver,
-							&isnull);
-	Assert(!isnull);
-	um->serverid = DatumGetObjectId(datum);
-
-	/* Extract the umoptions */
-	datum = SysCacheGetAttr(USERMAPPINGOID,
-							tp,
-							Anum_pg_user_mapping_umoptions,
-							&isnull);
-	if (isnull)
-		um->options = NIL;
-	else
-		um->options = untransformRelOptions(datum);
-
-	ReleaseSysCache(tp);
-
-	return um;
-}
 
 /*
  * GetUserMapping - look up the user mapping.
@@ -224,7 +174,23 @@ GetUserMapping(Oid userid, Oid serverid)
 	bool		isnull;
 	UserMapping *um;
 
-	tp = find_user_mapping(userid, serverid);
+	tp = SearchSysCache2(USERMAPPINGUSERSERVER,
+						 ObjectIdGetDatum(userid),
+						 ObjectIdGetDatum(serverid));
+
+	if (!HeapTupleIsValid(tp))
+	{
+		/* Not found for the specific user -- try PUBLIC */
+		tp = SearchSysCache2(USERMAPPINGUSERSERVER,
+							 ObjectIdGetDatum(InvalidOid),
+							 ObjectIdGetDatum(serverid));
+	}
+
+	if (!HeapTupleIsValid(tp))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("user mapping not found for \"%s\"",
+						MappingUserName(userid))));
 
 	um = (UserMapping *) palloc(sizeof(UserMapping));
 	um->umid = HeapTupleGetOid(tp);
@@ -246,60 +212,6 @@ GetUserMapping(Oid userid, Oid serverid)
 	return um;
 }
 
-/*
- * GetUserMappingId - look up the user mapping, and return its OID
- *
- * If no mapping is found for the supplied user, we also look for
- * PUBLIC mappings (userid == InvalidOid).
- */
-Oid
-GetUserMappingId(Oid userid, Oid serverid)
-{
-	HeapTuple	tp;
-	Oid			umid;
-
-	tp = find_user_mapping(userid, serverid);
-
-	/* Extract the Oid */
-	umid = HeapTupleGetOid(tp);
-
-	ReleaseSysCache(tp);
-
-	return umid;
-}
-
-/*
- * find_user_mapping - Guts of GetUserMapping family.
- *
- * If no mapping is found for the supplied user, we also look for
- * PUBLIC mappings (userid == InvalidOid).
- */
-static HeapTuple
-find_user_mapping(Oid userid, Oid serverid)
-{
-	HeapTuple	tp;
-
-	tp = SearchSysCache2(USERMAPPINGUSERSERVER,
-						 ObjectIdGetDatum(userid),
-						 ObjectIdGetDatum(serverid));
-
-	if (HeapTupleIsValid(tp))
-		return tp;
-
-	/* Not found for the specific user -- try PUBLIC */
-	tp = SearchSysCache2(USERMAPPINGUSERSERVER,
-						 ObjectIdGetDatum(InvalidOid),
-						 ObjectIdGetDatum(serverid));
-
-	if (!HeapTupleIsValid(tp))
-		ereport(ERROR,
-				(errcode(ERRCODE_UNDEFINED_OBJECT),
-				 errmsg("user mapping not found for \"%s\"",
-						MappingUserName(userid))));
-
-	return tp;
-}
-
 
 /*
  * GetForeignTable - look up the foreign table definition by relation oid.

src/include/foreign/foreign.h

@@ -72,8 +72,6 @@ typedef struct ForeignTable
 extern ForeignServer *GetForeignServer(Oid serverid);
 extern ForeignServer *GetForeignServerByName(const char *name, bool missing_ok);
 extern UserMapping *GetUserMapping(Oid userid, Oid serverid);
-extern Oid	GetUserMappingId(Oid userid, Oid serverid);
-extern UserMapping *GetUserMappingById(Oid umid);
 extern ForeignDataWrapper *GetForeignDataWrapper(Oid fdwid);
 extern ForeignDataWrapper *GetForeignDataWrapperByName(const char *name,
 							bool missing_ok);