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

Thanks, Pavel.

The function is the same between v15 and v17. Is there a subtle difference in performance for nested subqueries in v17?

--/
CREATE FUNCTION iq_get_stats_security_v1_4_4 (bigint, timestamp without time zone) RETURNS TABLE(value double precision, volume double precision, avg_price double precision, high_price double precision, low_price double precision, stock_date timestamp without time zone, bestbidprice double precision, bestbidsize double precision, bestofferprice double precision, bestoffersize double precision, last_trade_price double precision, close_price double precision, open_price double precision, prev_close_price double precision, outstanding_shares bigint)
VOLATILE
AS $body$
BEGIN
RETURN query

SELECT Cast(Round(Sum(STATS."value"), 4) AS double precision) AS "value",
Cast(Sum(STATS."volume") AS double precision) AS "volume",
Cast(Round(Sum(STATS."value"), 4) AS double precision)/Cast(Sum(STATS."volume") AS double precision) AS "avg_price",
Cast(Round(MAX(STATS."high_price"), 4) AS double precision) AS "high_price",
Cast(Round(MIN(STATS."low_price"), 4) AS double precision) AS "low_price",
MAX(STATS."stock_date") AS "stock_date",
Cast(MAX(BBO."bestbidprice") AS double precision),
Cast(MAX(BBO."bestbidsize") AS double precision),
Cast(MAX(BBO."bestofferprice") AS double precision),
Cast(MAX(BBO."bestoffersize") AS double precision),
Cast(MAX(LTP."trade_price") AS double precision),
Cast(MAX(CLOSEP."close_price")AS double precision),
Cast(MAX(OPENING."trade_price")AS double precision),
Cast(MAX(PREVCLOSEP."prev_close_price")AS double precision),
Cast(MAX(STOCKINFO."outstanding_shares") AS bigint) as "outstanding_shares"

FROM (

SELECT Sum(TRADES.executed_quantity * Cast(TRADES.execution_price AS DECIMAL) / 10000) AS "value",
Sum(TRADES.executed_quantity)AS "volume",
AVG(Cast(TRADES.execution_price AS DECIMAL) / 10000) AS "avg_price",
MAX(Cast(TRADES.execution_price AS DECIMAL) / 10000) AS "high_price",
MIN(Cast(TRADES.execution_price AS DECIMAL) / 10000) AS "low_price",
MAX(TRADES.msg_date) AS "stock_date"
FROM
(
SELECT distinct on (TRADES_P."trade_id") * from(

SELECT p.msg_date,p.executed_quantity,p.execution_price,
(p.match_number) AS "trade_id"
FROM PUBLIC.prod_itchbbo_p_small_message p
WHERE Date(p.msg_date) = $2
AND p.printable = 'Y'
AND p.order_book=$1
ORDER BY p.match_number DESC

) AS TRADES_P Order by "trade_id" ASC
)AS TRADES

) AS STATS
,
( Select Cast(best_bid_price AS double precision) / 10000 AS "bestbidprice",
Cast(best_bid_size AS double precision) AS "bestbidsize" ,
Cast(best_offer_price AS double precision) / 10000 AS "bestofferprice",
Cast(best_offer_size AS double precision) AS "bestoffersize"
FROM public.prod_itchbbo_o_message
WHERE order_book = $1
AND date(added_date)= $2

AND added_date::timestamp::time<=
(
SELECT s.msg_date::timestamp::time
FROM prod_itch_s_message s
WHERE s.event_code='M'
ORDER BY s.msg_date DESC limit 1
)
ORDER BY msg_date desc limit 1
) as BBO
,( select LASTTRADE.trade_price from

(
SELECT * from(SELECT (Cast(execution_price AS double precision) / 10000) AS "trade_price",
(match_number) AS "trade_id"
FROM PUBLIC.prod_itchbbo_p_small_message
WHERE order_book = $1
AND Date(added_date) = $2
AND printable = 'Y'
ORDER BY match_number DESC limit 1) AS TRADES_P

) AS LASTTRADE order by LASTTRADE.trade_id DESC limit 1 ) as LTP

,( select max(Cast(closePrice."close_price" AS double precision) )as "close_price" from(Select Cast(execution_price AS double precision) / 10000 as "close_price" from PUBLIC.prod_itchbbo_p_small_message
where date(msg_date)=$2
and executed_quantity = 0
and order_book =$1 order by msg_date DESC limit 1 )as closePrice)as CLOSEP

,( select FIRSTTRADE.trade_price from

(

SELECT * from(SELECT (Cast(execution_price AS double precision) / 10000) AS "trade_price",
(match_number) AS "trade_id"
FROM PUBLIC.prod_itchbbo_p_small_message
WHERE order_book = $1
AND Date(added_date) = $2
AND printable = 'Y'
ORDER BY match_number asc limit 1) AS TRADES_P

) AS FIRSTTRADE order by FIRSTTRADE.trade_id ASC limit 1

) as OPENING

,( Select Cast(price AS double precision) / 10000 as "prev_close_price" from public.prod_itch_a_message
where date(msg_date)=$2
and order_number = 0
and orderbook =$1 order by msg_date ASC limit 1 )as PREVCLOSEP

,( Select Cast(shares AS bigint) as "outstanding_shares" from public.prod_stock_information
where order_book = $1 and group_name = 'N' ) as STOCKINFO

;

END;
$body$ LANGUAGE plpgsql
/

From: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
Date: Monday, April 28, 2025 at 2:17 AM
To: marcos sicat <marcos(dot)sicat(at)atlasifs(dot)com>
Cc: pgsql-bugs(at)lists(dot)postgresql(dot)org <pgsql-bugs(at)lists(dot)postgresql(dot)org>
Subject: 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(dot)sicat(at)atlasifs(dot)com<mailto:marcos(dot)sicat(at)atlasifs(dot)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.png]
Server Info: Postgres 15

[image.png]

Query Performance:

Postgres 17:
[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.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