POSTGRES - 子查询返回结果非常慢

Question

I've a fairly simple query, but it includes a Sub - Query. I want to fetch list of resource_id which pass through a filter in ORDER BY DESC; order.

MORE INFORMATION Basically we need to find the list of resource_id's which pass through a filter mentioned in the query below,

   SELECT rs.resource_id
FROM resource rs
WHERE (
    SELECT rc.resource_id
    FROM risk_child rc
    WHERE rc.resource_id = rs.resource_id 
    AND rc.cloudaccount_id = rs.cloud_account_id
    AND rs.reg_id= any(array[236]) 
    AND rc.risk_level= any(array['high','low'])
    AND rc.status = any(array['fail'])
    AND rc.cloudaccount_id= any (array['4ZiCmwslbjhmRtHAOjLG'])
    ORDER BY rc.id DESC
    LIMIT 1
) = rs.resource_id

these resources would then be passed into another query as mentioned here:

SELECT
  DISTINCT ON (rc.resource_id, rc.rule_id, s.id) MAX(rc.creationtime) as creationtime,
  rc.resource_id,
  rl.rule_tag,
  s.service,
  r.region,
  rc.status,
  rs.vpc_id,
  rc.cloudaccount_id,
  rc.organization_id,
  rs.owner_id,
  rc.description,
  f.function_name,
  g.group_name,
  rc.risk_level,
  rc.id,
  rc.user_id,
  rc.pro_id,
  c.category_name,
  rc.raw as rawResponse,
  rs.res_ca_id,
  rs.resource_name
FROM
  risk_child rc,
  resource rs,
  rule rl,
  service s,
  region r,
  function f,
  g_by g,
  category c
WHERE
  rc.resource_id = rs.resource_id
  AND rl.id = rc.rule_id
  AND s.id = rs.ser_id
  AND rs.reg_id = r.id
  AND f.id = rc.function_id
  AND c.id = rc.category_id
  AND g.id = rc.group_id
  AND rc.cloudaccount_id like any (array $ { modifiedCloudAccounts })
  AND rc.organization_id = $ { orgId }
  AND rc.rule_id > 0
  AND rc.cloudaccount_id = rs.cloud_account_id
  AND rs.resource_id like any (array $ { getResources }) $ { risk }
GROUP BY
  rc.rule_id,
  rc.creationtime,
  rc.creationtime,
  rc.resource_id,
  rl.rule_tag,
  rl.id,
  s.service,
  r.region,
  rc.status,
  rs.vpc_id,
  rc.cloudaccount_id,
  rc.organization_id,
  rs.owner_id,
  rc.description,
  f.function_name,
  g.group_name,
  rc.risk_level,
  rc.id,
  rc.user_id,
  rc.pro_id,
  c.category_name,
  rc.raw,
  s.id,
  rs.res_ca_id
ORDER BY
  rc.resource_id,
  rc.rule_id ASC;

PROBLEM Now the first query returns the result very slow, even after indexing the result comes in 5 - 6 seconds. So keeping in mind the first query needs to run two times

1. One to get total number of Rows (For pagination)
2. Second time to get the resource_ids

I've mainly used NO - SQL for my apps so I am fairly new to SQL querying. Any help would be appreciated. Thanks

Answer 1

So finally this thing worked for my case:

    SELECT rs.resource_id
FROM resource rs
WHERE EXISTS (SELECT *
              FROM risk_child rc
              WHERE rc.resource_id = rs.resource_id 
                AND rc.cloudaccount_id = rs.cloud_account_id
                AND rs.reg_id= any(array[236]) 
                AND rc.risk_level= any(array['high','low'])
                AND rc.status = any(array['fail'])
                AND rc.cloudaccount_id= any (array['4ZiCmwslbjhmRtHAOjLG'])
             )

Basically as I had explained this in my post I am fairly new to SQL, I didn't put proper indexing in my tables so I had to add the following indexes to make the query faster

resource(resource_id, cloud_account_id) and risk_child(resource_id, cloudaccount_id) this helped me improve my performance even more.