如何识别Oracle死锁中涉及的行？

Question

当Oracle检测到死锁时，会写出这样的跟踪文件：

*** SESSION ID:(56.27081) 2012-05-14 08:16:28.013
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-0010002c-002719b5       146      56     X            164      44           X
TX-000f002a-002edd1e       164      44     X            146      56           X
session 56: DID 0001-0092-00050D0D       session 44: DID 0001-00A4-0002E3C2
session 44: DID 0001-00A4-0002E3C2       session 56: DID 0001-0092-00050D0D
Rows waited on:
Session 44: obj - rowid = 00035157 - AAA1FXAAxAAASfLAAn
  (dictionary objn - 217431, file - 49, block - 75723, slot - 39)
Session 56: obj - rowid = 00035157 - AAA1FXAAsAACjuiAAP
  (dictionary objn - 217431, file - 44, block - 670626, slot - 15)

如何根据上述信息确定所涉及的行，以帮助调试应用程序？

Answer 1

我找到了答案：

1. dictionary objn之后的数字可用于从DBA_objects中选择。

   SELECT owner, object_name, object_type 
   FROM dba_objects 
   WHERE object_id = 217431;
   

2. 识别完表后，可以使用rowid找到该行：

   SELECT * 
   FROM table_found_above 
   WHERE rowid = 'AAA1FXAAxAAASfLAAn';
   

如果跟踪文件说没有“Rows等待”，这种技术将无效。问题可能是由于未编入索引的外键。