版本12c中引入了dbms_stats 的一系列report_* 函数，用以在收集统计信息前 向用户汇报预备将执行的统计对象和统计情况。
例如report_gather_auto_stats
function report_gather_auto_stats (
detail_level varchar2 default ‘TYPICAL’,
format varchar2 default ‘TEXT’)
return clob;
—
— This procedure runs auto stats gathering job in reporting mode. That is,
— stats are not actually collected, but all the objects that will be
— affected when auto stats gathering is invoked are reported.
— The detail level for the report is defined by the detail_level
— input parameter. Please see the comments for report_single_stats_operation
— on possible values for detail_level and format.
具体使用：
SQL> variable c clob;
SQL> exec :c:=dbms_stats.report_gather_auto_stats();
PL/SQL procedure successfully completed.
SQL> set long 999
SQL> print :c;
C
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| Id | Operation | Target | Start Time | E
nd Time | Status | Total Tasks | Successful Tasks | Failed Tasks | Active Tasks
|
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| 1317 | gather_database_stats (auto) (reporting mode) | AUTO | |
| | 187 | | |
|
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T A S K S
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| | Target | Type | Start Tim
e | End Time | Status
| |
| —————————————————————————
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| | SYS.BBW | TABLE |
Comment