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Shutdown Immediate Hangs: Common Causes [ID 106474.1]

2016-11-25 15:45 2353 0 原创 Oracle 故障处理
作者: dave

Shutdown Immediate Hangs: Common Causes [ID 106474.1]


 

Modified 13-JUL-2007     Type PROBLEM     Status PUBLISHED

 

 

Problem Description

-------------------

 

Shutdown immediate hangs or goes very slowly.  You can shutdown abort

with no problem.

 

 

Solution Description

--------------------

 

There are two common causes of a shutdown immediate hanging.

These are:

 

   Rollbacks

   Temp segment cleanup

 

 

Explanation

-----------

 

Rollbacks: If a large dml statement is in progress it must roll back before

the shutdown completes.  In pre 8.1 versions of Oracle this can

be made to go faster with a higher cleanup_rollback_entries, but

http://www.cndba.cn/Dave/article/549

be careful because too high a setting can cause resource contention

http://www.cndba.cn/Dave/article/549

during normal database operation.http://www.cndba.cn/Dave/article/549

 

Temp segment cleanup:  If your tablespace used for temp sort segments

is of type temporary (as shown by the CONTENTS column of DBA_TABLESPACES)

the extents, once allocated, are never deallocated until shutdown. 

Instead they are tracked in the SGA.  This helps reduce dictionaryhttp://www.cndba.cn/Dave/article/549http://www.cndba.cn/Dave/article/549

cache contention during normal database operation.  Unfortunately,

when we shutdown these extents must all be deallocated at once whichhttp://www.cndba.cn/Dave/article/549

can lead to the dictionary cache contention we avoided while we were

running.  The tablespace of type temporary was introduced in 7.3.

http://www.cndba.cn/Dave/article/549

 

These two problems can also combine to make things even slower as a

rollback will also deallocate extents, leading to further contention

on the parts of the dictionary cache that track used and free extents.

 

 

References

----------

 

Note:1060831.6 cleanup_rollback_entries

Note:73439.1   Temporary Segment Handling

http://www.cndba.cn/Dave/article/549

 

 

 

 http://www.cndba.cn/Dave/article/549

 

 

 

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