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我们的服务器有 8 个内核，并且正在运行一个使用 postgres 作为数据库的 Web 应用程序（DHIS2）。

有一个大的选择查询需要几个小时才能执行。（查询是从终端执行的）当查询运行时，该查询进程的 CPU 利用率会跃升至恒定的 100%。

这会挂起应用程序，并且应用程序的页面甚至不会在浏览器中加载。这一定是因为其他 postgres 进程正在等待该查询的进程完成。

但是，当我们在机器中有多个内核时，为什么将单个内核的利用率达到 100% 会阻止其余进程的执行呢？

在这种情况下，我无法理解多 CPU 和内核的概念。postgres 不认识他们吗？选择查询对另一个查询的依赖关系是什么？

有人可以解释这种行为并提出一些管理大查询执行的方法，尽管可能是某种 postgres 配置？

Postgres Version - 9.6
OS - Ubuntu 16
Database Size - 200GB on disk
DHIS2 Version - 2.30

查询（计算异常值） -

select  datasets,
    max(ou1.name) Country, ou1.organisationunitid as Country__Id ,
    max(ou2.name) state, ou2.organisationunitid as State__Id ,
    max(ou3.name) Division, ou3.organisationunitid as Division__Id ,
    max(ou4.name) District, max(ou4.code) as District__Code, ou4.organisationunitid as District__Id, 
    max(ou5.name) Block, max(ou5.code) as Block__Code, ou5.organisationunitid as Block__Id,
    max(ou6.name) Facility, max(ou6.code) as Facility__Code,ou6.organisationunitid as Facility__Id,
    max(ou.name) as outlierfacility,
    max(de.name) as dataelement,
    max(coc.name) as category,
    concat(max(p.startdate),':',max(p.enddate)) as period,
    max(pt.name) as frequency,  
    _dv.value,
    u upperbound,
    l lowerbound,
    mean,
    std
from 
(
    with stats as (
        select  dv.sourceid,
            dv.dataelementid,
            dv.categoryoptioncomboid,
            dv.attributeoptioncomboid,
            array_agg(distinct dv.periodid) as periods,
            array_agg(distinct ds.name) as datasets,            
            avg(dv.value::float) as mean, 
            stddev(dv.value::float) as std
        from datavalue dv
        inner join datasetmembers dsm on dsm.dataelementid = dv.dataelementid
        inner join dataelement de on de.dataelementid = dsm.dataelementid
        inner join dataset ds on ds.datasetid = dsm.datasetid   
        inner join period pe on pe.periodid = dv.periodid
        inner join periodtype pt on pt.periodtypeid = pe.periodtypeid
        inner join categoryoptioncombo coc on dv.categoryoptioncomboid = coc.categoryoptioncomboid
        inner join _orgunitstructure ous on ous.organisationunitid = dv.sourceid
        where pe.startdate between date('2019-04-29') - interval '6 months' and date('2019-04-29') and pt.name='Monthly' 
        and de.valueType in ('NUMBER','INTEGER')
        and ds.uid in ('123qwe123','123ewq123')
        group by dv.sourceid,dv.dataelementid,dv.categoryoptioncomboid,dv.attributeoptioncomboid
    )
    select dv.*,datasets,mean,std,mean+3*std u,mean-3*std l
    from datavalue dv
    inner join period pe on pe.periodid = dv.periodid
    inner join periodtype pt on pt.periodtypeid = pe.periodtypeid   
    inner join stats on 
        stats.dataelementid = dv.dataelementid and 
        stats.sourceid= dv.sourceid and 
        stats.categoryoptioncomboid = dv.categoryoptioncomboid and 
        stats.attributeoptioncomboid = dv.attributeoptioncomboid
    where dv.periodid = any(periods)
    and (dv.value::float > mean+3*std or dv.value::float < mean-3*std)
) _dv
inner join dataelement de on _dv.dataelementid = de.dataelementid 
inner join categoryoptioncombo coc on _dv.categoryoptioncomboid = coc.categoryoptioncomboid
inner join _orgunitstructure ous on _dv.sourceid = ous.organisationunitid
inner join organisationunit ou on ou.organisationunitid = ous.organisationunitid
left join organisationunit ou1 on ou1.organisationunitid = ous.idlevel1
left join organisationunit ou2 on ou2.organisationunitid = ous.idlevel2
left join organisationunit ou3 on ou3.organisationunitid = ous.idlevel3
left join organisationunit ou4 on ou4.organisationunitid = ous.idlevel4
left join organisationunit ou5 on ou5.organisationunitid = ous.idlevel5
left join organisationunit ou6 on ou6.organisationunitid = ous.idlevel6
inner join period p on _dv.periodid = p.periodid
inner join periodtype pt on p.periodtypeid = pt.periodtypeid
group by ou1.organisationunitid,
ou2.organisationunitid,
ou3.organisationunitid,
ou4.organisationunitid,
ou5.organisationunitid,
ou6.organisationunitid,
_dv.dataelementid,_dv.sourceid,_dv.categoryoptioncomboid,_dv.attributeoptioncomboid,_dv.periodid,_dv.value,u,l,mean,std,datasets
order by country,state,division,district,block,facility,dataelement,category
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