Re: PG 12 slow selects from pg_settings

[Julius Tuskenis <julius.tuskenis@xxxxxxxxx>]

Thank you,  Ranier, 

v12.8 has improved the performance

PostgreSQL 12.8, compiled by Visual C++ build 1914, 64-bit:

```

Function Scan on pg_show_all_settings a  (cost=0.00..12.50 rows=5 width=485) (actual time=7.122..7.128 rows=1 loops=1)
  Filter: (name = 'standard_conforming_strings'::text)
  Rows Removed by Filter: 313
Planning Time: 0.083 ms
Execution Time: 7.204 ms

```

Would you please direct me to the change log or some bug report to read in detail what was causing the problem and how it was fixed?

Regards,

Julius Tuskenis

2021-10-08, pn, 14:01 Ranier Vilela <ranier.vf@xxxxxxxxx> rašė:

Em sex., 8 de out. de 2021 às 04:01, Julius Tuskenis <julius.tuskenis@xxxxxxxxx> escreveu:

Dear PostgreSQL community,

we have noticed a severe decrease in performance reading pg_catalog.pg_settings table in PostgreSQL 12 on MS Windows 10 machines compared to earlier versions.

```

explain (analyze, buffers, timing)
SELECT * from pg_catalog.pg_settings where name = 'standard_conforming_strings';

```

On PostgreSQL 12.5, compiled by Visual C++ build 1914, 64-bit:

Function Scan on pg_show_all_settings a  (cost=0.00..12.50 rows=5 width=485) (actual time=343.350..343.356 rows=1 loops=1)
  Filter: (name = 'standard_conforming_strings'::text)
  Rows Removed by Filter: 313
Planning Time: 0.079 ms
Execution Time: 343.397 ms

You can try 12.8 which is available now, there is a dll related fix that can make some improvement.

regards,

Ranier Vilela