enq: HW

select event,p1,p2,p3 from v$session  where event like 'enq%';

   	EVENT	P1	P2	P3
1	enq: HW - contention	1213661190	6	48639810
2	enq: HW - contention	1213661190	6	48639810



通过P3进行DBMS_UTILITY转换可以获知发生争用的文件和block 
SQL> select DBMS_UTILITY.DATA_BLOCK_ADDRESS_FILE(48639810) FILE#, 
   DBMS_UTILITY.DATA_BLOCK_ADDRESS_BLOCK(48639810) BLOCK# 
    from dual; 

   	FILE#	BLOCK#
1	11	2502466


select owner, segment_type, segment_name 
    from dba_extents 
    where file_id = 11
    and 2502466 between block_id and block_id + blocks - 1; 
         
		 
   	OWNER	SEGMENT_TYPE	SEGMENT_NAME
1	TLCB	TABLE	WEBSERVICE_MSG


原因：表空间满了,数据库忙于分配空间。

SQL> select parameter1,parameter2,parameter3 from v$event_name where name='enq: HW - contention'; 

PARAMETER1							 PARAMETER2							  PARAMETER3
---------------------------------------------------------------- ---------------------------------------------------------------- ----------------------------------------------------------------
name|mode							 table space #							  block


SELECT event, 
 p1, 
 p2, 
 p3, 
 Count(1) 
FROM dba_hist_active_sess_history 
WHERE event_id = 1645217925 
GROUP BY event, 
 p1, 
 p2, 
 p3;

EVENT                                   P1         P2         P3 COUNT(1)
--------------------- -------------------- ---------- ---------- --------
enq: HW - contention            1213661190         14   58720522     22681


我们得到信息从 dba_hist_active_sess_history,这个视图包含了最近系统活动的在内存里的信息。

下一步是用 dbms_utility包来确定当前文件号和块号

SELECT 
dbms_utility.Data_block_address_file(58720522)  FILE#,
dbms_utility.Data_block_address_block(58720522) BLOCK#
FROM   dual;

      FILE#     BLOCK#
---------- ----------
        14        266


Now we can use this information to get which segment it belongs too.

SELECT owner,
       segment_type,
       segment_name
FROM   dba_extents
WHERE  file_id = 14
       AND 266 BETWEEN block_id AND block_id + blocks - 1;

OWNER          SEGMENT_TYPE      SEGMENT_NAME
-------------  ----------------- -------------------------------------
XXXX          LOBSEGMENT         SYS_LOB0000014653C00008$$