今天是2014-03-12，在進行數據庫性能調優過程中，突然翻到了之前一封郵件，信息如下：
從日志中看，發現存在行級排他鎖存在爭用以致產生了死鎖。
問題描述：
*** 2013-12-02 17:03:10.148 DEADLOCK DETECTED ( ORA-00060 ) [Transaction Deadlock] The following deadlock is not an ORACLE error. It is a deadlock due to user error in the design of an application or from issuing incorrect ad-hoc SQL. The following information may aid in determining the deadlock: Deadlock graph: ---------Blocker(s)-------- ---------Waiter(s)--------- Resource Name process session holds waits process session holds waits TX-000b002b-002be2d3 61 958 X 141 876 X TX-0009001c-000d5ffa 141 876 X 61 958 X session 958: DID 0001-003D-00001BC1 session 876: DID 0001-008D-0000B424 session 876: DID 0001-008D-0000B424 session 958: DID 0001-003D-00001BC1 Rows waited on: Session 876: obj - rowid = 0000DE75 - AAAN51AArAAAA6mAAO (dictionary objn - 56949, file - 43, block - 3750, slot - 14) Session 958: obj - rowid = 00014F07 - AAAU8HABXAAA7BqAAI (dictionary objn - 85767, file - 87, block - 241770, slot - 8) Information on the OTHER waiting sessions: Session 876: sid: 876 ser: 38057 audsid: 7879846 user: 47/EPMFRAMEWORK flags: (0x41) USR/- flags_idl: (0x1) BSY/-/-/-/-/- flags2: (0x8) pid: 141 O/S info: user: orarep, term: UNKNOWN, ospid: 11195 image: oracle@pmsdb2 O/S info: user: webpms2, term: unknown, ospid: 1234, machine: pmsrep1 program: JDBC Thin Client application name: JDBC Thin Client, hash value=2546894660 Current SQL Statement: UPDATE AP_COLL_INFO_T T SET T.PROCINST_ID = NULL, T.IF_PROJECT_INHERITED = '0' WHERE T.INVEST_SNO = :1 End of information on OTHER waiting sessions. Current SQL statement for this session: UPDATE AP_PROJECT_INFO_EDITION_T T SET T.IF_INHERITED='1' WHERE T.AP_PRJ_SNO=:1 在上面可以獲得很多可以幫助診斷問題的信息，該信息顯示由於應用邏輯錯誤，導致了死鎖的產生。 另外還可以通過相關sql獲得一些簡要信息： eg：
2、分解rowid獲得產生死鎖等待的對象信息如下：
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、導致此問題的sql語句為：
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 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>
那麼本次鎖的最後組合為：tx x x；
最後總結一下（一見明了）：
參考（1507093.1）
