标签：style blog color os io 使用 for div log
1.explain plan的使用
SQL> explain plan for delete from t_jingyu; Explained. SQL> select * from table(dbms_xplan.display); PLAN_TABLE_OUTPUT -------------------------------------------------------------------------------------------------------------------------------------------- Plan hash value: 1368587462 ----------------------------------------------------------------------- | Id | Operation | Name | Rows | Cost (%CPU)| Time | ----------------------------------------------------------------------- | 0 | DELETE STATEMENT | | 1864K| 978 (2)| 00:00:12 | | 1 | DELETE | T_JINGYU | | | | | 2 | TABLE ACCESS FULL| T_JINGYU | 1864K| 978 (2)| 00:00:12 | ----------------------------------------------------------------------- Note ----- - dynamic sampling used for this statement (level=2) 13 rows selected
2.explain plan 只是显示执行计划，并不会真正执行delete语句·
SQL> select count(*) from t_jingyu; COUNT(*) ---------- 2097152
SQL Tuning 基础概述02 - explain plan的使用
标签：style blog color os io 使用 for div log
原文地址：http://www.cnblogs.com/jyzhao/p/3850022.html
