本文探讨了如何通过SQL查询优化提升数据库性能，重点关注查询执行次数、缓冲获取次数及读取次数之间的关系，并通过实例展示了如何筛选并分析关键查询以提高系统效率。
select *
from v$sqlarea v
where executions > 0
and buffer_gets > 0
and (buffer_gets - disk_reads) / buffer_gets < 0.8
order by v.user_io_wait_time desc
select executions,
disk_reads,
buffer_gets,
round((buffer_gets - disk_reads) / buffer_gets, 2) hit_radio,
round(disk_reads / executions, 2) reads_per_run,
sql_text
from v$sqlarea v
where v.parsing_schema_name = 'juqi'
and executions > 0
and buffer_gets > 0
and (buffer_gets - disk_reads) / buffer_gets < 0.8
order by 4 desc
from v$sqlarea v
where executions > 0
and buffer_gets > 0
and (buffer_gets - disk_reads) / buffer_gets < 0.8
order by v.user_io_wait_time desc
select executions,
disk_reads,
buffer_gets,
round((buffer_gets - disk_reads) / buffer_gets, 2) hit_radio,
round(disk_reads / executions, 2) reads_per_run,
sql_text
from v$sqlarea v
where v.parsing_schema_name = 'juqi'
and executions > 0
and buffer_gets > 0
and (buffer_gets - disk_reads) / buffer_gets < 0.8
order by 4 desc
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