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 SESSION_ID=47;  2    3    4  

SESSION_ID NAME 				  P1	     P2 	P3  WAIT_TIME CURRENT_OBJ# CURRENT_FILE# CURRENT_BLOCK#
---------- ------------------------------ ---------- ---------- ---------- ---------- ------------ ------------- --------------
	47 direct path read			   4	 439696 	 8	    0	     78043	       4	 434552
	47 direct path read			   4	 431152 	 8	    0	     78043	       4	 431144
	47 direct path read			   4	 427264 	 8	    0	     78043	       4	 427256
	47 direct path read			   4	 423712 	 8	    0	     78043	       4	 423704
	47 direct path read			   4	 416816 	 8	    0	     78043	       4	 416808
	47 direct path read			   4	 413088 	 8	    0	     78043	       4	 413080
	47 direct path read			   4	 409936 	 8	    0	     78043	       4	 409928
	47 direct path read			   4	 406112 	 8	    0	     78043	       4	 406104
	47 direct path read			   4	 401984 	 8	    0	     78043	       4	 401976
	47 direct path read			   4	 399248 	 8	    0	     78043	       4	 399240
	47 direct path read			   4	 394848 	 8	    0	     78043	       4	 394840

SESSION_ID NAME 				  P1	     P2 	P3  WAIT_TIME CURRENT_OBJ# CURRENT_FILE# CURRENT_BLOCK#
---------- ------------------------------ ---------- ---------- ---------- ---------- ------------ ------------- --------------
	47 direct path read			   4	 390672 	 8	    0	     78043	       4	 390664
	47 direct path read			   4	 388096 	 8	    0	     78043	       4	 388088
	47 direct path read			   4	 383856 	 8	    0	     78043	       4	 383848
	47 direct path read			   4	 380096 	 8	    0	     78043	       4	 380088
	47 direct path read			   4	 377488 	 8	    0	     78043	       4	 377480
	47 direct path read			   4	 373856 	 8	    0	     78043	       4	 373848
	47 direct path read			   4	 370128 	 8	    0	     78043	       4	 370120
	47 direct path read			   4	 366896 	 8	    0	     78043	       4	 366888
	47 direct path read			   4	 362544 	 8	    0	     78043	       4	 362536
	47 direct path read			   4	 358432 	 8	    0	     78043	       4	 358424
	47 direct path read			   4	 354928 	 8	    0	     78043	       4	 354920

SESSION_ID NAME 				  P1	     P2 	P3  WAIT_TIME CURRENT_OBJ# CURRENT_FILE# CURRENT_BLOCK#
---------- ------------------------------ ---------- ---------- ---------- ---------- ------------ ------------- --------------
	47 direct path read			   4	 350336 	 8	    0	     78043	       4	 350328
	47 direct path read			   4	 346624 	 8	    0	     78043	       4	 346616
	47 direct path read			   4	 343120 	 8	    0	     78043	       4	 343112
	47 direct path read			   4	 338960 	 8	    0	     78043	       4	 338952
	47 direct path read			   4	 337008 	 8	    0	     78043	       4	 337000
	47 direct path read			   4	 332688 	 8	    0	     78043	       4	 332680
	47 direct path read			   4	 329008 	 8	    0	     78043	       4	 329000
	47 direct path read			   4	 325536 	 8	    0	     78043	       4	 325528
	47 direct path read			   4	 321488 	 8	    0	     78043	       4	 321480
	47 direct path read			   4	 315920 	 8	    0	     78043	       4	 315912
	47 direct path read			   4	 306912 	 8	    0	     78043	       4	 306904

SQL> select name,a.PARAMETER1,a.PARAMETER2,a.PARAMETER3 from v$event_name a where name='direct path read';

NAME			       PARAMETER1      PARAMETER2 PARAMETER3
------------------------------ --------------- ---------- ----------------------------------------------------------------
direct path read	       file number     first dba  block cnt

P1:文件号

P2: 第一个数据块

P3:总共读了多少块

 select owner,segment_name,segment_type from dba_extents  
    where file_id = 4 and 427264 between block_id and block_id+blocks-1;SQL>   2  

OWNER			       SEGMENT_NAME									 SEGMENT_TYPE
------------------------------ --------------------------------------------------------------------------------- ------------------
TEST			       TEST1										 TABLE

11G中全表扫描也是这个等待事件。