获得optimal、onepass、multipass执行次数的百分比,很明显,optimal所占的百分比越高越好,假如onepass和multipass占的百分比很高,就不需要增加pga_aggregate_target的值了,或者调整SQL语句以使用更少的PGA区。
SQL>
select
optimal_count "Optimal",
round(optimal_count * 100 / total,2) "Optimal %",
onepass_count "OnePass",
round(onepass_count * 100 / total,2) "Onepass %",
multipass_count "MultiPass",
round(multipass_count * 100 / total,2) "Multipass %"
from
(select
sum(total_executions) total,
sum(optimal_executions) optimal_count,
sum(onepass_executions) onepass_count,
sum(multipasses_executions) multipass_count
from
v$sql_workarea_histogram
where total_executions <> 0) ;
Optimal Optimal % OnePass Onepass % MultiPass Multipass %
---------- ---------- ---------- ---------- ---------- -----------
402 99.01 4 0.99 0 0
而v$pgastat则提供了有关PGA使用的整体的概括性的信息。
SQL>
select * from v$pgastat;
select
name,
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