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oracle drm参数,DRM修隐藏参数达到停用

DRM的过程是十分迅速的,一般不会影响到RAC系统的应用。但是也存在一定的BUG,在10.2.0.3的版本之前可能出现Libary cache lock而导致实例挂起,这时可以考虑停用DRM,修改两个隐含参数即可:

_gc_affinity_time=0

_gc_undo_affinity=FALSE

metalink上Doc ID:  467777.1具体描述了这个truncate语句引发的案例。

remaster的过程中,lmd进程会在trace文件中如下日志信息:

*** 2009-06-24 08:29:48.257

* kjdrchkdrm: found an RM request in the request queue

Transfer pkey 56500 to node 0

*** 2009-06-24 08:29:48.337

Begin DRM(2343) - transfer pkey 56500 to 0 oscan 0.0

*** 2009-06-24 08:29:48.338

Begin DRM(2343) - transfer pkey 56524 to 0 oscan 0.0

ftd received from node 1 (26/0.31.0)

all ftds received

syncr inc 26 lvl 8873 from 1 rcvd (my inc,lvl: 26, 8872) (26/0.31.0)

ftd received from node 1 (26/0.34.0)

all ftds received

我碰到的一个类似的案例,在alert日志里记录的告警信息如下:

GES: Potential blocker (pid=385334) on resource LB-975F92C3-87052713;

enqueue info in file /u01/admin/erpdb/bdump/erpdb1_lmd0_635140.trc and DIAG trace file

检查DIAG trace file可以发现385334号进程的信息:

Dumping diagnostic information for ospid 385334:

OS pid = 385334

loadavg : 3.20 3.08 2.98

last wait for 'latch: row cache objects' blocking sess=0x0 seq=63971 wait_time=2351 seconds since wait started=940

address=700000579b64ca0, number=c7, tries=0

Dumping Session Wait History

for 'latch: row cache objects' count=1 wait_time=2351

address=700000579b64ca0, number=c7, tries=0

for 'latch: row cache objects' count=1 wait_time=25630

address=700000579b64ca0, number=c7, tries=0

for 'latch: row cache objects' count=1 wait_time=22914

address=700000579b64ca0, number=c7, tries=0