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RECYCLE池的CACHE特点(一)

SQL> ALTER TABLESPACE NDMAIN OFFLINE; Tablespace altered. SQL> ALTER TABLESPACE NDMAIN ONLINE; Tablespace altered. SQL> SELECT OBJECT_NAME, A.STATUS, COUNT(*) 2 FROM V$BH A, USER_OBJECTS B 3 WHERE A.OBJD = B.OBJECT_ID 4 AND OBJECT_NAME IN ('T', 'T2', 'T3') 5 GROUP BY OBJECT_NAME, A.STATUS; OBJECT_NAME STATU COUNT(*) ------------------------------ ----- ---------- T free 1 T2 free 4829 T3 free 3266 SQL> SELECT COUNT(*) FROM T3; COUNT(*) ---------- 167011 Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 4839 consistent gets 4829 physical reads 0 redo size 381 bytes sent via SQL*Net to client 503 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed SQL> SELECT COUNT(*) FROM T2; COUNT(*) ---------- 167011 Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 4839 consistent gets 4829 physical reads 0 redo size 381 bytes sent via SQL*Net to client 503 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed SQL> SELECT OBJECT_NAME, A.STATUS, COUNT(*) 2 FROM V$BH A, USER_OBJECTS B 3 WHERE A.OBJD = B.OBJECT_ID 4 AND OBJECT_NAME IN ('T', 'T2', 'T3') 5 GROUP BY OBJECT_NAME, A.STATUS; OBJECT_NAME STATU COUNT(*) ------------------------------ ----- ---------- T2 xcur 3267 T3 xcur 4829
由于T3先放到RECYCLE池中,T3的数据全部被CACHE,而T2表被部分CACHE。
SQL> SELECT COUNT(*) FROM T3; COUNT(*) ---------- 167011 Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 4839 consistent gets 0 physical reads 0 redo size 381 bytes sent via SQL*Net to client 503 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed SQL> SELECT COUNT(*) FROM T2; COUNT(*) ---------- 167011 Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 4839 consistent gets 1562 physical reads 0 redo size 381 bytes sent via SQL*Net to client 503 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed SQL> SELECT COUNT(*) FROM T2; COUNT(*) ---------- 167011 Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 4839 consistent gets 1562 physical reads 0 redo size 381 bytes sent via SQL*Net to client 503 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed SQL> SELECT OBJECT_NAME, A.STATUS, COUNT(*) 2 FROM V$BH A, USER_OBJECTS B 3 WHERE A.OBJD = B.OBJECT_ID 4 AND OBJECT_NAME IN ('T', 'T2', 'T3') 5 GROUP BY OBJECT_NAME, A.STATUS; OBJECT_NAME STATU COUNT(*) ------------------------------ ----- ---------- T2 xcur 3267 T3 xcur 4829


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