Re[3]: Postgresql planning time too high

I finnished testing with the matterialized view and the result is much 
improved, planning time goes down from 5.482 ms to 1507.741 ms.
This is much better but I still don't understand why postgres is 
planning so much time as long the main table is empty(there are no 
records in table focg).


------ Original Message ------
From: "Sterpu Victor" <[email protected]>
To: "Fırat Güleç" <[email protected]>
Cc: [email protected]
Sent: 2019-11-22 1:44:51 PM
Subject: Re[2]: Postgresql planning time too high

>No rows should be returned, DB is empty.
>I'm testing now on a empty DB trying to find out how to improve this.
>
>In this query I have 3 joins like this:
>
>SELECT t1.id, t2.valid_from
>FROM t1
>JOIN t2 ON (t1.id_t1 = t1.id)
>LEFT JOIN t3 ON (t3.id_t1 = t1.id AND t3.valid_from<t2.valid_from)
>WHERE t3.id IS NULL
>
>If I delete these 3 joins than the planning time goes down from 5.482 
>ms to 754.708 ms but I'm not sure why this context is so demanding on 
>the planner.
>I'm tryng now to make a materialized view that will allow me to stop 
>using the syntax above.
>
>I reattached the same files, they should be fine like this.
>
>
>
>
>------ Original Message ------
>From: "Fırat Güleç" <[email protected]>
>To: "Sterpu Victor" <[email protected]>
>Cc: [email protected]
>Sent: 2019-11-22 1:35:15 PM
>Subject: RE: Postgresql planning time too high
>
>>Hello Sterpu,
>>
>>
>>
>>First, please run vaccum for your Postgresql DB.
>>
>>
>>
>>No rows returned from your query. Could you double check your query 
>>criteria.
>>
>>
>>
>>After that could you send explain analyze again .
>>
>>
>>
>>Regards,
>>
>>
>>
>>FIRAT GÜLEÇ
>>Infrastructure & Database Operations Manager
>>[email protected]
>>
>>
>>
>>M: 0 532 210 57 18
>>İnönü Mh. Mimar Sinan Cd. No:3 Güzeller Org.San.Bölg. GEBZE / KOCAELİ
>>
>>
>>
>>
>>
>>
>>
>>
>>From: Sterpu Victor <[email protected]>
>>Sent: Friday, November 22, 2019 2:21 PM
>>To:[email protected]
>>Subject: Postgresql planning time too high
>>
>>
>>
>>Hello
>>
>>
>>
>>I'm on a PostgreSQL 12.1 and I just restored a database from a backup.
>>
>>When I run a query I get a big execution time: 5.482 ms
>>
>>After running EXPLAIN ANALYZE I can see that the "Planning Time: 
>>5165.742 ms" and the "Execution Time: 6.244 ms".
>>
>>The database is new(no need to vacuum) and i'm the only one connected 
>>to it. I use a single partition on the harddrive.
>>
>>I also tried this on a postgresql 9.5 and the result was the same.
>>
>>I'm not sure what to do to improve this situation.
>>
>>The query and the explain is attached.
>>
>>
>>
>>Thank you
>>
>>
>>