Oracle 性能相关常用脚本(SQL)

在缺乏的可视化工具来监控数据库性能的情形下，常用的脚本就派上用场了，下面提供几个关于Oracle性能相关的脚本供大家参考。以下脚本均在Oracle 10g测试通过，Oracle 11g可能要做相应调整。

1、寻找最多BUFFER_GETS开销的SQL 语句

--filename: top_sql_by_buffer_gets.sql
--Identify heavy SQL (Get the SQL with heavy BUFFER_GETS)
SET LINESIZE 190
COL sql_text FORMAT a100 WRAP
SET PAGESIZE 100

SELECT *
  FROM (  SELECT sql_text,
                sql_id,
                executions,
                disk_reads,
                buffer_gets
            FROM v$sqlarea
          WHERE DECODE (executions, 0, buffer_gets, buffer_gets / executions) >
                    (SELECT AVG (DECODE (executions, 0, buffer_gets, buffer_gets / executions))
                            + STDDEV (DECODE (executions, 0, buffer_gets, buffer_gets / executions))
                      FROM v$sqlarea)
                AND parsing_user_id != 3D
        ORDER BY 4 DESC) x
 WHERE ROWNUM <= 10;

2、寻找最多DISK_READS开销的SQL 语句

--filename:top_sql_disk_reads.sql
--Identify heavy SQL (Get the SQL with heavy DISK_READS)
SET LINESIZE 190
COL sql_text FORMAT a100 WRAP
SET PAGESIZE 100

SELECT *
  FROM (  SELECT sql_text,
                sql_id,
                executions,
                disk_reads,
                buffer_gets
            FROM v$sqlarea
          WHERE DECODE (executions, 0, disk_reads, disk_reads / executions) >
                    (SELECT AVG (DECODE (executions, 0, disk_reads, disk_reads / executions))
                            + STDDEV (DECODE (executions, 0, disk_reads, disk_reads / executions))
                      FROM v$sqlarea)
                AND parsing_user_id != 3D
        ORDER BY 3 DESC) x
 WHERE ROWNUM <= 10