Re: Postgres 17.4 is much slower than Postgres 15.12 using RECURSIVE

Hi

po 28. 4. 2025 v 7:37 odesílatel marcos sicat <marcos.sicat@atlasifs.com>
napsal:

>
> Postgres 17 version: PostgreSQL 17.4 on x86_64-pc-linux-gnu, compiled by
> Debian clang version 12.0.1, 64-bit
>
> Postgres 15 version: PostgreSQL 15.12 on x86_64-pc-linux-gnu, compiled by
> Debian clang version 12.0.1, 64-bit
>
>
>
> Description of Bug:
>
> Using RECURSIVE in Postgres 17 is much slower than Postgres 15
>
> Postgres 17.4 : 6.533 seconds
> Postgres 15.12: 1.564 seconds
>
> Same table objects, same tables indexes, same number of records
>
> I ran vacuum, analyze, reindex, and cache (pg_warm) on both Postgres 17
> and 15.
>
> Note: I also used LATERAL, postgres 15 performance is superior
> than postgres17. Postgres15 timings is 2.3 compared to Postgres17 timings
> is avg 7 seconds.
>
> SQL:
>
> WITH RECURSIVE stock AS
> (
> SELECT  prod.order_book,
>         prod.symbol,
>         value::numeric(20,4),
>         volume::numeric,
>         prev_close_price::numeric(20,4),
>         open_price::numeric(20,4),
>         low_price::numeric(20,4),
>         high_price::numeric(20,4),
>         last_trade_price::numeric(20,4),
>         avg_price::numeric(20,4),
>         close_price::numeric(20,4),
>         bestbidprice::numeric(20,4),
>         bestbidsize::numeric(20,0),
>         bestofferprice::numeric(20,4),
>         bestoffersize::numeric(20,0),
>        (((last_trade_price - prev_close_price)/prev_close_price)*100)::numeric(10,2) AS percentage
> FROM vw_pse_traded_companies prod,
> iq_get_stats_security_v1_4_4(prod.order_book,(
>     (   SELECT
>             DATE(d.added_date) AS DATE
>         FROM
>             prod_itchbbo_s_small_message d
>         ORDER BY
>             d.added_date DESC
>         LIMIT
>             1))::TIMESTAMP without TIME zone)
> WHERE
>   prod.group_name = 'N'
> )
> select * from stock where value is NOT NULL;
>
>
> Server Info: Postgres 17
>
> [image: image.png]
> Server Info: Postgres 15
>
> [image: image.png]
>
> Query Performance:
>
> Postgres 17:
> [image: image.png]
>
> QUERY PLAN
> CTE Scan on stock  (cost=35697.80..43197.80 rows=373125 width=812) (actual time=28.778..6526.084 rows=241 loops=1)
>   Filter: (value IS NOT NULL)
>   Rows Removed by Filter: 138
>   CTE stock
>     ->  Nested Loop  (cost=68.11..35697.80 rows=375000 width=300) (actual time=4.819..6524.963 rows=379 loops=1)
>           InitPlan 1
>             ->  Limit  (cost=1.60..1.60 rows=1 width=12) (actual time=0.027..0.028 rows=1 loops=1)
>                   ->  Sort  (cost=1.60..1.68 rows=34 width=12) (actual time=0.027..0.028 rows=1 loops=1)
>                         Sort Key: d.added_date DESC
>                         Sort Method: top-N heapsort  Memory: 25kB
>                         ->  Seq Scan on prod_itchbbo_s_small_message d  (cost=0.00..1.43 rows=34 width=12) (actual time=0.004..0.008 rows=34 loops=1)
>           ->  Sort  (cost=66.26..67.20 rows=375 width=4291) (actual time=0.442..0.666 rows=379 loops=1)
>                 Sort Key: info.order_book, listed.symbol
>                 Sort Method: quicksort  Memory: 42kB
>                 ->  Hash Join  (cost=18.62..50.23 rows=375 width=4291) (actual time=0.120..0.328 rows=379 loops=1)
>                       Hash Cond: ((info.symbol)::text = (listed.symbol)::text)
>                       ->  Seq Scan on prod_stock_information info  (cost=0.00..30.60 rows=380 width=12) (actual time=0.008..0.123 rows=380 loops=1)
>                             Filter: ((group_name)::text = 'N'::text)
>                             Rows Removed by Filter: 388
>                       ->  Hash  (cost=13.83..13.83 rows=383 width=4) (actual time=0.082..0.082 rows=383 loops=1)
>                             Buckets: 1024  Batches: 1  Memory Usage: 22kB
>                             ->  Seq Scan on prod_pse_listed_companies listed  (cost=0.00..13.83 rows=383 width=4) (actual time=0.003..0.038 rows=383 loops=1)
>           ->  Function Scan on iq_get_stats_security_v1_4_4  (cost=0.25..10.25 rows=1000 width=104) (actual time=17.197..17.197 rows=1 loops=379)
> Planning Time: 0.999 ms
> Execution Time: 6526.908 ms
>
>
> Postgres 15:
>
> [image: image.png]
>
> QUERY PLAN
> CTE Scan on stock  (cost=35697.80..43197.80 rows=373125 width=812) (actual time=7.746..1443.691 rows=241 loops=1)
>   Filter: (value IS NOT NULL)
>   Rows Removed by Filter: 138
>   CTE stock
>     ->  Nested Loop  (cost=68.11..35697.80 rows=375000 width=300) (actual time=2.426..1443.143 rows=379 loops=1)
>           InitPlan 1 (returns $0)
>             ->  Limit  (cost=1.60..1.60 rows=1 width=12) (actual time=0.015..0.016 rows=1 loops=1)
>                   ->  Sort  (cost=1.60..1.68 rows=34 width=12) (actual time=0.014..0.014 rows=1 loops=1)
>                         Sort Key: d.added_date DESC
>                         Sort Method: top-N heapsort  Memory: 25kB
>                         ->  Seq Scan on prod_itchbbo_s_small_message d  (cost=0.00..1.43 rows=34 width=12) (actual time=0.005..0.008 rows=34 loops=1)
>           ->  Sort  (cost=66.26..67.20 rows=375 width=4291) (actual time=0.466..0.563 rows=379 loops=1)
>                 Sort Key: info.order_book, listed.symbol
>                 Sort Method: quicksort  Memory: 51kB
>                 ->  Hash Join  (cost=18.62..50.23 rows=375 width=4291) (actual time=0.131..0.357 rows=379 loops=1)
>                       Hash Cond: ((info.symbol)::text = (listed.symbol)::text)
>                       ->  Seq Scan on prod_stock_information info  (cost=0.00..30.60 rows=380 width=12) (actual time=0.009..0.146 rows=380 loops=1)
>                             Filter: ((group_name)::text = 'N'::text)
>                             Rows Removed by Filter: 388
>                       ->  Hash  (cost=13.83..13.83 rows=383 width=4) (actual time=0.106..0.107 rows=383 loops=1)
>                             Buckets: 1024  Batches: 1  Memory Usage: 22kB
>                             ->  Seq Scan on prod_pse_listed_companies listed  (cost=0.00..13.83 rows=383 width=4) (actual time=0.005..0.061 rows=383 loops=1)
>           ->  Function Scan on iq_get_stats_security_v1_4_4  (cost=0.25..10.25 rows=1000 width=104) (actual time=3.797..3.797 rows=1 loops=379)
> Planning Time: 0.428 ms
> Execution Time: 1443.823 ms
>
>
The plan is same, but the execution of

iq_get_stats_security_v1_4_4

is 4x slower - 17ms x 4 ms, so you should to check
iq_get_stats_security_v1_4_4

Regards

Pavel