查找数据库中的topsql语句 (oracle)

1、查找使用资源最多的 SQL 语句：
（较高的磁盘读取（disk_reads消耗I/O）和较高的逻辑读取（buffer_gets消耗CPU）被用作衡量标准）
select sql_text from
(select sql_text,executions,buffer_gets,disk_reads
from v$sql
where buffer_gets > 100000
or disk_reads > 100000
order by buffer_gets + 100*disk_reads DESC)
where rownum <= 5;

2、查找使用CPU最多的SQL语句：
（较高的逻辑读取（buffer_gets消耗CPU）被用作衡量标准）
select sql_text from
(select sql_text,executions,buffer_gets,disk_reads
from v$sql
where buffer_gets > 100000
order by buffer_gets desc)
where rownum <= 5;
或者
（直接使用v$sql里的cpu_time）
select sql_text,
round(cpu_time/1000000, 2) cpu_seconds from
(select * from v$sql order by cpu_time desc)
where rownum <= 5;


3、查找使用磁盘I/O最多的SQL语句：
（较高的磁盘读取（disk_reads消耗I/O）被用作衡量标准）
select sql_text from
(select sql_text,executions,buffer_gets,disk_reads
from v$sql
where disk_reads > 100000
order by disk_reads desc)
where rownum <= 5;

4、查找占用 数据库 时间最多的SQL语句：
select sql_text,round(elapsed_time/1000000, 2) elapsed_seconds,executions from
(select * from v$sql order by elapsed_time desc)
where rownum <= 5;

5、查找执行次数（executions）最多的SQL语句：
select sql_text, executions from
(select * from v$sql
where executions > 1000
order by executions desc)
where rownum <= 5;

6、查找解析调用最多的SQL语句：
select sql_text,parse_calls from
(select * from v$sql
where parse_calls > 1000
order by parse_calls desc)
where rownum <= 5;

7、查找使用共享内存最多的SQL语句：
（使用共享内存大于1048576（bytes）的SQL语句会显示）
select sql_text,sharable_mem from
(select * from v$sql
where sharable_mem > 1048576
order by sharable_mem desc)
where rownum <= 5;