如何减少优化的查询执行时间？

Question

Hi this current Query is taking too long to execute, what changes should be made to reduce the execution time?

EXPLAIN ANALYZE
SELECT  date_trunc({{period}}, wb.timestamp),
        CAST(COUNT(DISTINCT(org.id)) AS float) / CAST(COUNT(DISTINCT(wb.anonymous_id)) AS float) AS "marketing-lead conversion rate"
FROM website_prod.pages wb
FULL JOIN core_prod.organizations_organization org ON CAST(wb.timestamp AS DATE) = CAST(org.created_at AS DATE)
WHERE   NOT org.is_internal 
        AND wb.timestamp > date_trunc('month', CURRENT_DATE) - INTERVAL '1 year'
        AND org.created_at > date_trunc('month', CURRENT_DATE) - INTERVAL '1 year'
GROUP BY 1

QUERY PLAN

Sort Key: ((org.created_at)::date)
Sort Method: quicksort Memory: 608kB
-> Seq Scan on organizations_organization org (cost=0.00..259.02 rows=5080 width=19) (actual time=0.017..6.266 rows=5316 loops=1)
Filter: ((NOT is_internal) AND (created_at > (date_trunc('month'::text, (('now'::cstring)::date)::timestamp with time zone) - '1 year'::interval)))
Rows Removed by Filter: 1540
-> Materialize (cost=69882.44..71012.63 rows=226038 width=45) (actual time=541.950..849.952 rows=3917712 loops=1)
-> Sort (cost=69882.44..70447.54 rows=226038 width=45) (actual time=541.945..592.666 rows=232720 loops=1)
Sort Key: ((wb."timestamp")::date)
Sort Method: external merge Disk: 14104kB
-> Seq Scan on pages wb (cost=0.00..42826.15 rows=226038 width=45) (actual time=40.801..358.687 rows=232720 loops=1)
Filter: ("timestamp" > (date_trunc('month'::text, (('now'::cstring)::date)::timestamp with time zone) - '1 year'::interval))
Rows Removed by Filter: 72766
Planning time: 0.214 ms
Execution time: 26614.737 ms

Answer 1

Your join looks extremely suspect to me...

  website_prod.pages wb
FULL JOIN
  core_prod.organizations_organization org
    ON CAST(wb.timestamp AS DATE) = CAST(org.created_at AS DATE)

In this case, you're joining all the rows in wb to all the rows in org , provided that they're "for" the same date.

So, for example, if on a particular date (say, 2021-04-01 ), there are 10 wb records and 10 org records, the join will give all 100 combinations.

• Is that REALLY what you want???

I would "expect" something more like...

  website_prod.pages wb
FULL JOIN
  core_prod.organizations_organization org
    ON  wb.some_key = org.some_key
    AND CAST(wb.timestamp AS DATE) = CAST(org.created_at AS DATE)

Also, to make the join effective, the plan shows that it's having to sort the data in to time order.

You haven't specifically shown what indexes exist, but for the current query you would benefit from indexes on the columns being joined... wb.timestamp and org.created_at . Though that would change if you changed the join predicate as described above.