ORACLE数据库性能 查询无索引sql

Question

oracle数据库在实时监控sql性能时怎么筛选那些没有索引的，性能差的sql语句，需要实时的，最好能自主选择一段时间的

Answer 1

SELECT sql_text, executions,

ROUND(disk_reads / executions, 2) reads_per_run,

disk_reads, buffer_gets,

ROUND((buffer_gets - disk_reads)

/ buffer_gets, 2) hit_ratio,

sql_text

FROM v$sqlarea

WHERE executions > 0

AND buffer_gets > 0

AND (buffer_gets - disk_reads) / buffer_gets < 0.80

ORDER by 3 desc ;