我有多个主题，具有不同的Transactions和EntityManagers，必须刷新对象的事件。要刷新这些事件，首先我删除旧的>新的。使用一个线程它可以正常工作，但有几个线程在删除事件时会发生死锁。
所有线程正在删除不同的对象，有时也会删除不同的表。那为什么这场资源竞争会发生呢？ 我正在使用主键来JPA阻止正确的对象。我查看是否有其他代码也使用该资源，但我没有找到它。 JPA是锁定整个表而不是行吗？
Exception in thread "Thread-4" javax.persistence.PersistenceException: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.6.0.v20150309-bf26070): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: java.sql.SQLException: ORA-00060: deadlock detected while waiting for resource
Error Code: 60
Call: DELETE FROM event WHERE ((id = ?) AND (version = ?))
bind => [426687, 1]
Query: DeleteObjectQuery(Event[id=426687,tipo=BDE,status=1,data=java.util.GregorianCalendar[time=1431489600000,areFieldsSet=true,areAllFieldsSet=true,lenient=true,zone=sun.util.calendar.ZoneInfo[id="America/New_York",offset=-18000000,dstSavings=3600000,useDaylight=true,transitions=235,lastRule=java.util.SimpleTimeZone[id=America/New_York,offset=-18000000,dstSavings=3600000,useDaylight=true,startYear=0,startMode=3,startMonth=2,startDay=8,startDayOfWeek=1,startTime=7200000,startTimeMode=0,endMode=3,endMonth=10,endDay=1,endDayOfWeek=1,endTim
这是OOracle跟踪文件。
*** 2015-07-05 15:21:02.351
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
TM-00007874-00000000 44 29 SX 51 185 SX SSX
TX-00020021-00000a5f 51 185 X 44 29 X
session 29: DID 0001-002C-0000000D session 185: DID 0001-0033-00000004
session 185: DID 0001-0033-00000004 session 29: DID 0001-002C-0000000D
Rows waited on:
Session 29: obj - rowid = 00007874 - AAAHh0AABAAAO2fAAX
(dictionary objn - 30836, file - 1, block - 60831, slot - 23)
Session 185: no row
----- Information for the OTHER waiting sessions -----
Session 185:
sid: 185 ser: 3883 audsid: 422763 user: 55/LUPAZUL_DEV
flags: (0x41) USR/- flags_idl: (0x1) BSY/-/-/-/-/-
flags2: (0x40009) -/-
pid: 51 O/S info: user: oracle, term: UNKNOWN, ospid: 9977
image: oracle@sydney-oracle11gexpress
client details:
O/S info: user: Pickler, term: unknown, ospid: 1234
machine: MacBook program: JDBC Thin Client
application name: JDBC Thin Client, hash value=2546894660
current SQL:
DELETE FROM correios_event WHERE ((id = :1 ) AND (version = :2 ))
----- End of information for the OTHER waiting sessions -----
Information for THIS session:
----- Current SQL Statement for this session (sql_id=fcrp8hfyatd79) -----
DELETE FROM correios_destiny WHERE ((id = :1 ) AND (version = :2 ))
答案 0 :(得分：2)
我解决了这个错误。
我有两个双向@OneToOne关系的JPA实体。当我调用EntityManager.remove（）时，我没有通过关系的所有者。这使得Oracle抛出了DeadLockException。
这样EclipseLink就要删除的同一个实体创建了两个语句。 这对我来说似乎是一个bug，JPA实现应该处理这个问题。