结论是存储在 remote 端,这其实也很好理解。在远端能高效率地计算,当然应当在远端完成缓存和检索。■ Before query execution via DBLINK:===========DBLINK destination (remote side):conn u2 / u2create table tab002 as select * from dba_objects;shu immediatestartupselect o.owner, o.object_name, o.object_type, s.buffer_pool, count (*) buffer from dba_objects o, v $ bh b, dba_segments s where b.objd = o.data_object_id and o.owner = 'U 2' and o.object_name = s.segment_name and o.object_type = s.segment_type group by o.owner, o.object_name, o.object_type, o.status, s.buffer_pool order by buffers;A record was not selected.===========Local side:conn u3 / u3select o.owner, o.object_name, o.object_type, s.buffer_pool, count (*) buffer from dba_objects o, v $ bh b, dba_segments s where b.objd = o.data_object_id and o.owner = 'U 2' and o.object_name = s.segment_name and o.object_type = s.segment_type group by o.owner, o.object_name, o.object_type, o.status, s.buffer_pool order by buffers;A record was not selected.select o.owner, o.object_name, o.object_type, s.buffer_pool, count (*) buffer from dba_objects o, v $ bh b, dba_segments s where b.objd = o.data_object_id and o.owner = 'U3' and o.object_name = s.segment_name and o.object_type = s.segment_type group by o.owner, o.object_name, o.object_type, o.status, s.buffer_pool order by buffers;A record was not selected.■ Query execution via DBLINK:SQL> select count (*) from tab002 @ dbk;COUNT (*)---------- 69263conn u3 / u3select o.owner, o.object_name, o.object_type, s.buffer_pool, count (*) buffer from dba_objects o, v $ bh b, dba_segments s where b.objd = o.data_object_id and o.owner = 'U 2' and o.object_name = s.segment_name and o.object_type = s.segment_type group by o.owner, o.object_name, o.object_type, o.status, s.buffer_pool order by buffers;A record was not selected. <<<<<<<<<<< Cache has no related informationselect o.owner, o.object_name, o.object_type, s.buffer_pool, count (*) buffer from dba_objects o, v $ bh b, dba_segments s where b.objd = o.data_object_id and o.owner = 'U3' and o.object_name = s.segment_name and o.object_type = s.segment_type group by o.owner, o.object_name, o.object_type, o.status, s.buffer_pool order by buffers;A record was not selected. <<<<<<<<<<< Cache has no related information===========DBLINK destination (remote side):select o.owner, o.object_name, o.object_type, s.buffer_pool, count (*) buffer from dba_objects o, v $ bh b, dba_segments s where b.objd = o.data_object_id and o.owner = 'U 2' and o.object_name = s.segment_name and o.object_type = s.segment_type group by o.owner, o.object_name, o.object_type, o.status, s.buffer_pool order by buffers;OWNER-------------------------------------------------------------------- ------------------------------OBJECT_NAME-------------------------------------------------------------------- ------------------------------OBJECT_TYPE BUFFER_POOL-------------------------------------------------------------------- ------- --------------------- BUFFERS----------U2TAB 002TABLE DEFAULT 2042 <<<<<<<<<<<<<<<<<< data got into the cache.select o.owner, o.object_name, o.object_type, s.buffer_pool, count (*) buffer from dba_objects o, v $ bh b, dba_segments s where b.objd = o.data_object_id and o.owner = 'U3' and o.object_name = s.segment_name and o.object_type = s.segment_type group by o.owner, o.object_name, o.object_type, o.status, s.buffer_pool order by buffers;A record was not selected.
本文转自健哥的数据花园博客园博客,原文链接:http://www.cnblogs.com/gaojian/p/7575226.html,如需转载请自行联系原作者