在Oracle Database 10g中,Oracle优化器的缺省模式由以前的CHOOSE,更改为现在的ALL_ROWS.
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$ sqlplus "/ as sysdba"
SQL*Plus: Release 10.1.0.2.0 - Production on Wed Mar 3 11:30:55 2004
Copyright (c) 1982, 2004, Oracle.All rights reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.1.0.2.0 - 64bit Production
With the Partitioning, OLAP and Data Mining options
SQL> show parameter optimizer_mode
NAME
TYPEVALUE
------------------------------------ ----------- ------------------------------
optimizer_mode
string'ALL_ROWS'
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这表明了Oracle在推动CBO优化器使用的坚定决心.