今天是2014-03-12,在进行数据库性能调优过程中,突然翻到了之前一封邮件,信息如下:
从日志中看,发现存在行级排他锁存在争用以致产生了死锁。
问题描述:
2、分解rowid获得产生死锁等待的对象信息如下:
SQL> select a.owner,
2 a.object_name,
3 a.object_type,
4 a.last_ddl_time,
5 a.created,
6 a.status,
7 b.object,
8 b.fno,
9 b.rownu,
10 b.block
11 from (select dbms_rowid.rowid_object('AAAU8HABXAAA7BqAAI') object,
12 dbms_rowid.rowid_relative_fno('AAAU8HABXAAA7BqAAI') fno,
13 dbms_rowid.rowid_row_number('AAAU8HABXAAA7BqAAI') rowNU,
14 dbms_rowid.rowid_block_number('AAAU8HABXAAA7BqAAI') block
15 from dual) b,
16 dba_objects a
17 where a.object_id = b.object;
OWNER OBJECT_NAME OBJECT_TYPE LAST_DDL_TIME CREATED STATUS OBJECT FNO ROWNU BLOCK
------------------------------ -------------------------------------------------------------------------------- ------------------- ------------- ----------- ------- ---------- ---------- ---------- ----------
EPMFRAMEWORK AP_PROJECT_INFO_EDITION_T TABLE 2013-11-27 11 2012-06-05 VALID 85767 87 8 241770
SQL>
SQL> select a.owner,
2 a.object_name,
3 a.object_type,
4 a.last_ddl_time,
5 a.created,
6 a.status,
7 b.object,
8 b.fno,
9 b.rownu,
10 b.block
11 from (select dbms_rowid.rowid_object('AAAN51AArAAAA6mAAO') object,
12 dbms_rowid.rowid_relative_fno('AAAN51AArAAAA6mAAO') fno,
13 dbms_rowid.rowid_row_number('AAAN51AArAAAA6mAAO') rowNU,
14 dbms_rowid.rowid_block_number('AAAN51AArAAAA6mAAO') block
15 from dual) b,
16 dba_objects a
17 where a.object_id = b.object;
OWNER OBJECT_NAME OBJECT_TYPE LAST_DDL_TIME CREATED STATUS OBJECT FNO ROWNU BLOCK
------------------------------ -------------------------------------------------------------------------------- ------------------- ------------- ----------- ------- ---------- ---------- ---------- ----------
EPMFRAMEWORK AP_COLL_INFO_T TABLE 2012-04-01 21 2011-10-05 VALID 56949 43 14 3750
SQL>
3、导致此问题的sql语句为:
SQL> SELECT B.SQL_ID,SQL_FULLTEXT,B.EVENT,B.SAMPLE_TIME,B.SESSION_ID FROM V$sqL A INNER JOIN (
2 select session_id, session_serial#, sql_id, event, SAMPLE_TIME
3 from dba_hist_active_sess_history
4 where event = 'enq: TX - row lock contention'
5 and sample_time >
6 to_date('2013-12-02 17:02:00', 'YYYY-MM-DD HH24:MI:SS') ) B
7 ON A.SQL_ID=B.SQL_ID;
SQL_ID SQL_FULLTEXT </SPAN> EVENT SAMPLE_TIME SESSION_ID
------------- -------------------------------------------------------------------------------------------------------------- ---------------------------------------------------------------- -------------------------------------------------------------------------------- ----------
9bwcgrn96cx62 INSERT INTO rt_actinst_data(instance_id,name,type,data,merge_type,rdata_app)VALUES(:1,:2,:3,:4,:5,:6) enq: TX - row lock contention 02-12月-13 05.03.21.158 下午 959
9bwcgrn96cx62 INSERT INTO rt_actinst_data(instance_id,name,type,data,merge_type,rdata_app)VALUES(:1,:2,:3,:4,:5,:6) enq: TX - row lock contention 02-12月-13 05.03.11.158 下午 959
1npq5jnavnc0k UPDATE AP_PROJECT_INFO_EDITION_T T SET T.IF_INHERITED='1' WHERE T.AP_PRJ_SNO=:1 enq: TX - row lock contention 02-12月-13 05.03.01.153 下午 958
9bwcgrn96cx62 INSERT INTO rt_actinst_data(instance_id,name,type,data,merge_type,rdata_app)VALUES(:1,:2,:3,:4,:5,:6) enq: TX - row lock contention 02-12月-13 05.03.01.153 下午 959
1npq5jnavnc0k UPDATE AP_PROJECT_INFO_EDITION_T T SET T.IF_INHERITED='1' WHERE T.AP_PRJ_SNO=:1 enq: TX - row lock contention 02-12月-13 05.02.51.148 下午 958
1npq5jnavnc0k UPDATE AP_PROJECT_INFO_EDITION_T T SET T.IF_INHERITED='1' WHERE T.AP_PRJ_SNO=:1 enq: TX - row lock contention 02-12月-13 05.02.41.148 下午 958
1npq5jnavnc0k UPDATE AP_PROJECT_INFO_EDITION_T T SET T.IF_INHERITED='1' WHERE T.AP_PRJ_SNO=:1 enq: TX - row lock contention 02-12月-13 05.02.31.148 下午 958
7 rows selected
SQL>
我要说的是在trace中可以获得一个deadlock graph:
看个例子:
那么本次锁的最后组合为:tx x x;
最后总结一下(一见明了):
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