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oracle 9i与10g中plan_table的不同：
oracle 9i中查看plan_table:
sys@dg1> select * from v$version;
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oracle9i enterprise edition release 9.2.0.4.0 - production
pl/sql release 9.2.0.4.0 - production
core 9.2.0.3.0 production
tns for linux: version 9.2.0.4.0 - production
nlsrtl version 9.2.0.4.0 - production
sys@dg1> set autotrace on explain;
sys@dg1> select * from plan_table;
no rows selected
execution plan
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0 select statement optimizer=choose
1 0 table access (full) of 'plan_table'
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oracle 10g中查看plan_table:
sql> select * from v$version;
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oracle database 10g enterprise edition release 10.2.0.2.0 - prod
pl/sql release 10.2.0.2.0 - production
core 10.2.0.2.0 production
tns for solaris: version 10.2.0.2.0 - production
nlsrtl version 10.2.0.2.0 - production
sql> set autotrace on explain
sql> select * from plan_table;
no rows selected
execution plan
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plan hash value: 103984305
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| id | operation | name | rows | bytes | cost (%cpu)| time
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| 0 | select statement | | 1 | 11081 | 2 (0)| 00:00:01
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| 1 | table access full| plan_table$ | 1 | 11081 | 2 (0)| 00:00:01
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note
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- dynamic sampling used for this statement
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结论：
oracle 10g中不再需要创建plan_table表,因为它会自动创建一个数据字典表plan_table$。
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