如何启用或者关闭RECO 分布式事务自动解决进程

Maclean Liu(刘相兵

如何启用或者关闭RECO 分布式事务自动解决进程

Disabling and Enabling RECO

The RECO background process of an Oracle Database instance automatically resolves failures involving distributed transactions. At exponentially growing time intervals, the RECO background process of a node attempts to recover the local portion of an in-doubt distributed transaction.

RECO can use an existing connection or establish a new connection to other nodes involved in the failed transaction. When a connection is established, RECO automatically resolves all in-doubt transactions. Rows corresponding to any resolved in-doubt transactions are automatically removed from the pending transaction table of each database.

You can enable and disable RECO using the ALTER SYSTEM statement with the ENABLE/DISABLE DISTRIBUTED RECOVERY options. For example, you can temporarily disable RECO to force the failure of a two-phase commit and manually resolve the in-doubt transaction.

The following statement disables RECO:

ALTER SYSTEM DISABLE DISTRIBUTED RECOVERY;
Alternatively, the following statement enables RECO so that in-doubt transactions are automatically resolved:

ALTER SYSTEM ENABLE DISTRIBUTED RECOVERY;
Note:
Single-process instances (for example, a PC running MS-DOS) have no separate background processes, and therefore no RECO process. Therefore, when a single-process instance that participates in a distributed system is started, you must manually enable distributed recovery using the preceding statement.