10046中的p1,p2,p3参数与实际块编号不符
我用alter session set events '10046 trace name context forever,level 12'
跟踪一个查询:select * from emp_reg where empno=100表emp_reg在empno列有索引.
跟踪显示有如下三个I/O:
WAIT #1: nam='db file sequential read' ela= 5725 p1=16 p2=1314 p3=1
WAIT #1: nam='db file sequential read' ela= 211 p1=16 p2=1315 p3=1
WAIT #1: nam='db file sequential read' ela= 199 p1=16 p2=1311 p3=1
p1,p2,p3分别为文件、块与读块个数。现在p1=16是对的,但p2=1314 1315 1311跟本和表所在的块不符。
使用show_space显示的表emp_reg的所在块:
SQL> exec show_space('EMP_REG');
Free Blocks.............................0
Total Blocks............................768
Total Bytes.............................3145728
Unused Blocks...........................176
Unused Bytes............................720896
Last Used Ext FileId....................16
Last Used Ext BlockId...................1809
Last Used Block.........................80
这上empno列上的索引的所在块
SQL> exec show_space('PK_EMP_REG',user,'INDEX');
Free Blocks.............................0
Total Blocks............................224
Total Bytes.............................917504
Unused Blocks...........................10
Unused Bytes............................40960
Last Used Ext FileId....................16
Last Used Ext BlockId...................1521
Last Used Block.........................6
这是为什么啊?
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