V$SESSION 找不到SQL_ID

--本方法基于ORACLE11G

实验：

SQL> create table test_1205 as select * from dba_objects;
Table created

SQL> select sid from v$mystat where rownum=1;
SID
----------
1155

SQL> update test_1205 set owner='WMZ' where object_id<100;
98 rows updated

在1155这个SESSION里面执行一个UPDATE，不要提交。

SQL> select sid from v$mystat where rownum=1;
SID
----------
1529

SQL> update test_1205 set owner='WMZ' where object_id<10;

--在1529里面跑另外一个UPDATE，因为1155没提交，1529处于行锁等待。

这个时候通过如下脚本去查询数据库：

select inst_id,
sid,
sql_id,
event,
blocking_session,
blocking_instance
from gv$session a
where blocking_session is not null;

 --查询SQL_ID 对应的内容

 select sql_text from v$sql where sql_id='72cbkgkmx1477';

 --查询1155对应的SQL_ID

--确实，SQL_ID是空的，那我去查询PREV_SQL_ID，这个SQL_ID是事物的SQL_ID，并不是UPDATE的SQL_ID

select prev_sql_id from gv$session where inst_id=1 and sid=1155;

 

 select sql_text from gv$sql where sql_id='9m7787camwh4m';

--另外一种方法

select PREV_EXEC_START,USERNAME,MODULE,ACTION FROM GV$SESSION WHERE INST_ID=1 AND SID=1155;

 

 SELECT SQL_ID,SQL_TEXT,LAST_ACTIVE_TIME,MODULE,ACTION FROM GV$SQL WHERE INST_ID=1 AND LAST_ACTIVE_TIME=TO_DATE('2018-12-05 17:38:15','YYYY-MM-DD HH24:MI:SS');

---至此找到没有提交的SQL_ID 以及SQL 内容！

请注意：

1.在高并发的情况下，可能会出现多个可疑SQL

2.UPDATE执行过后，又继续执行新的SQL，就悲催了，这个时候要自己把所有SQL抓出来，按照时间线排序，CHECK

----check

select a.inst_id, a.sid, a.sql_id, b.sql_id, b.sql_text
from gv$session a, gv$sql b
where a.inst_id = b.inst_id
and a.PREV_EXEC_START = b.LAST_ACTIVE_TIME
and a.USERNAME = b.PARSING_SCHEMA_NAME
and a.MODULE = b.MODULE
--and a.ACTION_HASH = b.ACTION_HASH

select a.inst_id,
a.sid,
a.event,
a.sql_id,
b.sql_text running_sql,
c.sql_in_session,
c.sql_id_in_v$sql,
c.sql_text blocking_sql,
a.blocking_session,
a.blocking_instance
from gv$session a,
(select sql_id, sql_text
from (select sql_id,
sql_text,
row_number() over(partition by sql_id order by sql_id) as rn
from gv$sql)
where rn = 1) b,
(select a.inst_id,
a.sid,
a.sql_id sql_in_session,
b.sql_id sql_id_in_v$sql,
b.sql_text
from gv$session a, gv$sql b
where a.inst_id = b.inst_id
and a.PREV_EXEC_START =b.LAST_ACTIVE_TIME
and a.USERNAME = b.PARSING_SCHEMA_NAME
and a.MODULE = b.MODULE
) c
where a.sql_id = b.sql_id
and a.blocking_session is not null
and a.BLOCKING_SESSION = c.sid
and a.BLOCKING_INSTANCE = c.inst_id;