Statistics ---------------------------- 0 recursive calls :递归调用。一般原因:dictionary cache未命中;动态存储扩展;PL/SQL语句 0 db block gets :bufer中读取的block数量,用于insert,update,delete,select for update 174530 consistent gets :bufer中读取的用于查询(除掉select for update)的block数量。 db blocks gets+consistent gets= logical read 0 physical reads :从磁盘上读取的block数量 0 redo size :bytes,写到redo logs的数据量 3546854 bytes sent via SQL*Net to client 60244 bytes received via SQL*Net from client 5433 SQL*Net roundtrips to/from client 0 sorts (memory) :内存排序次数 0 sorts (disk) :磁盘排序次数;与sort_area_size有关 81467 rows processed --以xstddxx2为驱动表,与xstddxx1产生嵌套循环连接 -------***************************************************************************************************--------------- 查看用户下的统计信息 SELECT * FROM user_tab_statistics; 执行用户统计: SQL> exec dbms_stats.gather_schema_stats(ownname => 'SCOTT',options => 'GATHER AUTO',estimate_percent => dbms_stats.auto_sample_size,method_opt => 'for all columns size repeat',degree => 15); SQL> EXEC DBMS_STATS.delete_table_stats('',tabname => '
'); SQL> EXEC DBMS_STATS.LOCK_TABLE_STATS ('', '
'); 手工统计信息存储过程 CREATE OR REPLACE PROCEDURE proc_manual_gather_stats AS t_count number; t_num_rows number; t_tablename varchar2(50); t_sql varchar2(200); CURSOR c1 IS select * from all_tables where wner = 'SCOTT'; BEGIN