Isolation threads not safe...


Project CONPY 
Server version: 10.11.6-MariaDB-0+deb12u1 Debian 12
version conpy:  mariadb 1.1.10

using mode:  thread_handling = pool-of-threads

A flask webapp, using mariadb.ConnectionPool for pooling connection

http server : gunicorn (10 workers and with threads class of worker (gevent or gthread) )


- for each worker, and instance of my webapp is created.
- each instance create a pool (mariadb.ConnectionPool) named 'poolName_' + worker.pid, on the same DB with the same user.

worker1 ->- pool1  ->>-- connections 1,2,3,4,5,6,7,8,9,10
worker2 ->- pool2  ->>-- connections 11,12,13,14,15,16,17,18,19,20
worker3 ->- pool3  ->>-- connections 21,22,23,24,25,26,27,28,29,30

so worker1 calling pool1.get-connection should return only  connections 1,2,3,4,5,6,7,8,9,10

When looking to my logs i can see that : 

1/ calling dbpool.get_connection() return  an connection from other pool!! 
worker2 ->- pool2  ->>-- connections 1,3,8,12,21,22,15
worker3 ->- pool3  ->>-- connections 2,3,12,25
ccl: pools share connections

2/pool object are used by different workers (you can say its a flask pb)
worker2 ->- pool2 
worker3 ->- pool2 
ccl: workers share pools

Is it a bug or a feature?
is it a problem for production use?



log worker pool and connection are folowed by their id.
on teardown i close the db (release to the pool)
(.venv) admin@mynode:~/webapp$$ gunicorn -w 3 -k gevent -c gunicorn_conf.py -b 0.0.0.0:8001 webapp:wsgiapp
[2025-01-29 17:07:46 +0000] [2612171] [INFO] Starting gunicorn 23.0.0
[2025-01-29 17:07:46 +0000] [2612171] [INFO] Listening at: http://0.0.0.0:8001 (2612171)
[2025-01-29 17:07:46 +0000] [2612171] [INFO] Using worker: gevent
[2025-01-29 17:07:46 +0000] [2612192] [INFO] Booting worker with pid: 2612192
[2025-01-29 17:07:46 +0000] [2612195] [INFO] Booting worker with pid: 2612195
[2025-01-29 17:07:46 +0000] [2612203] [INFO] Booting worker with pid: 2612203
set_cached 4 man@oze22222
->Create_dbpool id=(140700283773840) name= poolName_2612195 size=6 user=webappdev host=localhost
get_db_cnx_from_pool CREATE DBPOOL: worker: 2612195 dbpool: (140700283773840)
get_db_cnx_from_pool NEXCNX : worker: 2612195 dbpool: (140700283773840) Newcnx: (140700274546384)
Poolcnx(teardown):db.close()140700274546384[e256d0>]
set_cached 4 man@oze22222
->Create_dbpool id=(140700283773840) name= poolName_2612203 size=6 user=webappdev host=localhost
get_db_cnx_from_pool CREATE DBPOOL: worker: 2612203 dbpool: (140700283773840)
get_db_cnx_from_pool NEXCNX : worker: 2612203 dbpool: (140700283773840) Newcnx: (140700274562768)
Poolcnx(teardown):db.close()140700274562768[e296d0>]
set_cached 10 Lucsemb
->Create_dbpool id=(140700274271120) name= poolName_2612192 size=6 user=webappdev host=localhost
get_db_cnx_from_pool CREATE DBPOOL: worker: 2612192 dbpool: (140700274271120)
get_db_cnx_from_pool NEXCNX : worker: 2612192 dbpool: (140700274271120) Newcnx: (140700274546384)
Poolcnx(teardown):db.close()140700274546384[e256d0>]
set_cached 10 Lucsemb
get_db_cnx_from_pool NEXCNX : worker: 2612195 dbpool: (140700283773840) Newcnx: (140700274546704)
Poolcnx(teardown):db.close()140700274546704[e25810>]
set_cached 4 man@oze22222
get_db_cnx_from_pool NEXCNX : worker: 2612192 dbpool: (140700274271120) Newcnx: (140700274546704)
Poolcnx(teardown):db.close()140700274546704[e25810>]
set_cached 10 Lucsemb
get_db_cnx_from_pool NEXCNX : worker: 2612195 dbpool: (140700283773840) Newcnx: (140700274547024)
Poolcnx(teardown):db.close()140700274547024[e25950>]
set_cached 4 man@oze22222
get_db_cnx_from_pool NEXCNX : worker: 2612192 dbpool: (140700274271120) Newcnx: (140700274547024)
Poolcnx(teardown):db.close()140700274547024[e25950>]
set_cached 10 Lucsemb
get_db_cnx_from_pool NEXCNX : worker: 2612195 dbpool: (140700283773840) Newcnx: (140700274547344)
Poolcnx(teardown):db.close()140700274547344[e25a90>]
set_cached 4 man@oze22222
get_db_cnx_from_pool NEXCNX : worker: 2612195 dbpool: (140700283773840) Newcnx: (140700274547664)
Poolcnx(teardown):db.close()140700274547664[e25bd0>]
set_cached 10 Lucsemb
get_db_cnx_from_pool NEXCNX : worker: 2612192 dbpool: (140700274271120) Newcnx: (140700274547344)
Poolcnx(teardown):db.close()140700274547344[e25a90>]
set_cached 4 man@oze22222
get_db_cnx_from_pool NEXCNX : worker: 2612195 dbpool: (140700283773840) Newcnx: (140700274547984)
Poolcnx(teardown):db.close()140700274547984[e25d10>]
set_cached 10 Lucsemb
get_db_cnx_from_pool NEXCNX : worker: 2612192 dbpool: (140700274271120) Newcnx: (140700274547664)
Poolcnx(teardown):db.close()140700274547664[e25bd0>]
set_cached 4 man@oze22222
get_db_cnx_from_pool NEXCNX : worker: 2612203 dbpool: (140700283773840) Newcnx: (140700274563088)
Poolcnx(teardown):db.close()140700274563088[e29810>]
set_cached 10 Lucsemb
get_db_cnx_from_pool NEXCNX : worker: 2612192 dbpool: (140700274271120) Newcnx: (140700274547984)
Poolcnx(teardown):db.close()140700274547984[e25d10>]
set_cached 4 man@oze22222
get_db_cnx_from_pool NEXCNX : worker: 2612195 dbpool: (140700283773840) Newcnx: (140700274546384)
Poolcnx(teardown):db.close()140700274546384[e256d0>]
set_cached 10 Lucsemb
get_db_cnx_from_pool NEXCNX : worker: 2612192 dbpool: (140700274271120) Newcnx: (140700274546384)
Poolcnx(teardown):db.close()140700274546384[e256d0>]
set_cached 4 man@oze22222
get_db_cnx_from_pool NEXCNX : worker: 2612195 dbpool: (140700283773840) Newcnx: (140700274546704)
Poolcnx(teardown):db.close()140700274546704[e25810>]
set_cached 10 Lucsemb
get_db_cnx_from_pool NEXCNX : worker: 2612192 dbpool: (140700274271120) Newcnx: (140700274546704)
Poolcnx(teardown):db.close()140700274546704[e25810>]