RE: Recovery performance of DROP DATABASE with many tablespaces

Hi, Fujii-san

I came across this post and I got interested in it,
 so I tried to apply/test the patch but I am not sure if I did it correctly.
I set-up master-slave sync, 200GB shared_buffers, 20000 max_locks_per_transaction,
1 DB with 500 table partitions shared evenly across 5 tablespaces.

After dropping the db, with or without patch, 
there were no difference in recovery performance when dropping database, 
so maybe I made a mistake somewhere. But anyway, here's the results.

======WITHOUT PATCH=======
[200GB shared buffers]
DROPDB only (skipped DROP TABLE and DROP TABLESPACE)
2018/07/04_13:35:00.161
dropdb
2018/07/04_13:35:05.591        5.591 sec

[200GB shared_buffers]
DROPDB (including DROP TABLE and DROP TABLESPACE)
real    3m19.717s
user    0m0.001s
sys     0m0.001s

======WITH PATCH=======
[200GB shared_buffers]
DROPDB only (skipped DROP TABLE and DROP TABLESPACE)
2018/07/04_14:19:47.128
dropdb
2018/07/04_14:19:53.177        6.049 sec

[200GB shared_buffers]
DROPDB (included the DROP TABLE and DROP TABLESPACE commands)
real    3m51.834s
user    0m0.001s
sys     0m0.002s

Just in case, do you also have some performance test numbers/case 
to show the recovery perf improvement when dropping database that contain multiple tablespaces?

Regards,
Kirk Jamison