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DBWR enhancements In Oracle10g II

我们注意到,在Oracle9iR2中,和DBWR相关的统计事件有12个,分别为:

SQL> select * from v$version;
BANNER
----------------------------------------------------------------
Oracle9i Enterprise Edition Release 9.2.0.4.0 - Production
PL/SQL Release 9.2.0.4.0 - Production
CORE    9.2.0.3.0       Production
TNS for Linux: Version 9.2.0.4.0 - Production
NLSRTL Version 9.2.0.4.0 - Production
SQL> select name from v$statname where name like '%DBWR%';
NAME
----------------------------------------------------------------
DBWR checkpoint buffers written
DBWR transaction table writes
DBWR undo block writes
DBWR revisited being-written buffer
DBWR make free requests
DBWR free buffers found
DBWR lru scans
DBWR summed scan depth
DBWR buffers scanned
DBWR checkpoints
DBWR cross instance writes
DBWR fusion writes
12 rows selected. 

在Oracle10gR1中,这类事件上升为15个:

SQL> select * from v$version;
BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.1.0.3.0 - 64bi
PL/SQL Release 10.1.0.3.0 - Production
CORE    10.1.0.3.0      Production
TNS for Solaris: Version 10.1.0.3.0 - Production
NLSRTL Version 10.1.0.3.0 - Production
SQL> select name from v$statname where name like '%DBWR%';
NAME
----------------------------------------------------------------
DBWR checkpoint buffers written
DBWR thread checkpoint buffers written
DBWR tablespace checkpoint buffers written
DBWR parallel query checkpoint buffers written
DBWR object drop buffers written

DBWR transaction table writes
DBWR undo block writes
DBWR revisited being-written buffer
DBWR make free requests
DBWR free buffers found
DBWR lru scans
DBWR summed scan depth
DBWR buffers scanned
DBWR checkpoints
DBWR fusion writes
15 rows selected. 

而在Oracle10gR2中,这个数字再次减少到12个,3个事件已经被废弃:

SQL> select * from v$version;
BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Prod
PL/SQL Release 10.2.0.1.0 - Production
CORE    10.2.0.1.0      Production
TNS for Linux: Version 10.2.0.1.0 - Production
NLSRTL Version 10.2.0.1.0 - Production
SQL> select name from v$statname where name like '%DBWR%';
NAME
----------------------------------------------------------------
DBWR checkpoint buffers written
DBWR thread checkpoint buffers written
DBWR tablespace checkpoint buffers written
DBWR parallel query checkpoint buffers written
DBWR object drop buffers written
DBWR transaction table writes
DBWR undo block writes
DBWR revisited being-written buffer
DBWR make free requests
DBWR lru scans
DBWR checkpoints
DBWR fusion writes
12 rows selected. 

废弃的三个事件为:

DBWR free buffers found  
DBWR summed scan depth  
DBWR buffers scanned    

DBWR的行为在Oracle10g中已经改变.

 


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By eygle on 2006-02-08 22:57 | Comments (0) | Internal | 672 |


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