分别在这两种情况下执行插入，用tkprof生成统计信息文件，对比如下：

insert into test select * from bc_log_1                                         
                                                                                
                                                                                
call     count       cpu    elapsed       disk      query    current        rows
------- ------  -------- ---------- ---------- ---------- ----------  ----------
Parse        1      0.00       0.02          0          0          0           0
Execute      1      5.88      30.35      20935      39792      85865      564546
Fetch        0      0.00       0.00          0          0          0           0
------- ------  -------- ---------- ---------- ---------- ----------  ----------
total        2      5.88      30.37      20935      39792      85865      564546
                                                                                
Misses in library cache during parse: 1                                         
Optimizer goal: CHOOSE                                                          
Parsing user id: 26                                                             
                                                                                
Rows     Row Source Operation                                                   
-------  ---------------------------------------------------                    
 564546  TABLE ACCESS FULL BC_LOG_1 (cr=22885 r=20870 w=0 time=5441181 us)      
                                                                                
                                                                                
Elapsed times include waiting on following events:                              
  Event waited on                             Times   Max. Wait  Total Waited   
  ----------------------------------------   Waited  ----------  ------------   
  db file scattered read                       1333        0.15          3.11   
  log buffer space                              149        0.36          7.92   
  log file switch completion                     18        0.99          2.14   
  free buffer waits                              12        0.93          6.31   
  latch free                                      1        0.00          0.00   
  db file sequential read                        65        0.04          0.22   
  log file switch (checkpoint incomplete)         8        0.99          3.13   
  SQL*Net message to client                       1        0.00          0.00   
  SQL*Net message from client                     1       11.30         11.30   

insert /*+ append */ into bc_log select * from bc_log_1                           
                                                                                  
                                                                                  
call     count       cpu    elapsed       disk      query    current        rows  
------- ------  -------- ---------- ---------- ---------- ----------  ----------  
Parse        1      0.01       0.22          0          1          0           0  
Execute      1      4.88      23.11      22879      27806       1109      564546  
Fetch        0      0.00       0.00          0          0          0           0  
------- ------  -------- ---------- ---------- ---------- ----------  ----------  
total        2      4.89      23.34      22879      27807       1109      564546  
                                                                                  
Misses in library cache during parse: 1                                           
Optimizer goal: CHOOSE                                                            
Parsing user id: 26                                                               
                                                                                  
Rows     Row Source Operation                                                     
-------  ---------------------------------------------------                      
      1  LOAD AS SELECT  (cr=27806 r=22879 w=14883 time=23097417 us)              
 564546   TABLE ACCESS FULL BC_LOG_1 (cr=27209 r=22878 w=0 time=15937799 us)      
                                                                                  
                                                                                  
Elapsed times include waiting on following events:                                
  Event waited on                             Times   Max. Wait  Total Waited     
  ----------------------------------------   Waited  ----------  ------------     
  control file sequential read                    3        0.00          0.00     
  db file sequential read                        27        0.01          0.04     
  db file scattered read                       1440        1.07         11.45     
  free buffer waits                              23        0.99          3.11     
  latch free                                      1        0.01          0.01     
  direct path write                               2        0.00          0.00     
  SQL*Net message to client                       1        0.00          0.00     
  SQL*Net message from client                     1       16.89         16.89     

可以看出，使用/*+ append */后，一致读和当前读的数量均低于不使用hints，尤其是当前读的数量大大降低，cpu time和elapsed time均有所降低。