前几天说过,Oracle10g Events CONTROLF的改变,当时猜测控制文件的变化可能是为了满足Oracle10g Grid运算支持大量并行实例的需要。
单实例节点控制文件转储包含的位图如下:
Database checkpoint: Thread=1 scn: 0x0000.0007276a Threads: #Enabled=1, #Open=1, Head=1, Tail=1 enabled threads: 01000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
今天转储了一个RAC数据库的控制文件,验证了这个猜测:
*************************************************************************** DATABASE ENTRY *************************************************************************** (size = 316, compat size = 316, section max = 1, section in-use = 1, last-recid= 0, old-recno = 0, last-recno = 0) (extent = 1, blkno = 1, numrecs = 1) 12/27/2006 16:25:27 DB Name "EYGLE" Database flags = 0x00404000 0x00001000 Controlfile Creation Timestamp 12/27/2006 16:25:30 Incmplt recovery scn: 0x0000.00000000 Resetlogs scn: 0x0000.00000001 Resetlogs Timestamp 12/27/2006 16:25:27 Prior resetlogs scn: 0x0000.00000000 Prior resetlogs Timestamp 01/01/1988 00:00:00 Redo Version: compatible=0xa200100 #Data files = 5, #Online files = 5 Database checkpoint: Thread=2 scn: 0x0000.008a8531 Threads: #Enabled=2, #Open=2, Head=2, Tail=1 enabled threads: 01100000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
Oracle不断的将位图引入数据库的各个治理单元,显然旨在性能提高。
-The End-
http://www.eygle.com/archives/2007/02/controlfile_bitmap.Html
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