direct path read

11g 全表扫描等待事件为:direct path read
SQL> select SESSION_ID,
       NAME,
       P1,
       P2,
       P3,
       WAIT_TIME,
       CURRENT_OBJ#,
       CURRENT_FILE#,
       CURRENT_BLOCK#
  from v$active_session_history ash, v$event_name enm
 where ash.event# = enm.event#
and ash.session_id=32;  2    3    4    5    6    7    8    9   10   11   12  

SESSION_ID NAME 				  P1	     P2 	P3  WAIT_TIME CURRENT_OBJ# CURRENT_FILE# CURRENT_BLOCK#
---------- ------------------------------ ---------- ---------- ---------- ---------- ------------ ------------- --------------
	32 direct path read			   4	 189072 	 8	    0	     78499	       4	 189065
	32 db file sequential read		   4	1714365 	 1	    0	     78499	       4	1795583
	32 direct path read			   4	1795080 	 8	    0	     78499	       4	1795072
	32 direct path read			   4	1789896 	 8	    0	     78499	       4	1789888
	32 direct path read			   4	1785384 	 8	    0	     78499	       4	1785376
	32 direct path read			   4	1775752 	 8	    0	     78499	       4	1775744
	32 direct path read			   4	1771656 	 8	    0	     78499	       4	1771648
	32 direct path read			   4	1766280 	 8	    0	     78499	       4	1766272
	32 direct path read			   4	1761416 	 8	    0	     78499	       4	1761408
	32 direct path read			   4	1757720 	 8	    0	     78499	       4	1757712
	32 direct path read			   4	1749560 	 8	    0	     78499	       4	1749552
	32 direct path read			   4	1745880 	 8	    0	     78499	       4	1745872

P1 要读取的绝对文件号码

P2 读取的起始块号

P3 要读取的块数
SQL> select owner, segment_name, segment_type
  from dba_extents
 where file_id = 4
   and  1714365 between block_id
   and block_id + blocks - 1;  2    3    4    5  

OWNER			       SEGMENT_NAME									 SEGMENT_TYPE
------------------------------ --------------------------------------------------------------------------------- ------------------
SCOTT			       TEST_1										 TABLE