Steps to reproduce:
Install odoo in GCP VM and connecting to GCP Cloud SQL.
I tested odoo with normal PostgreSQL installation in GCP VM and everything working fine but with GCP Cloud SQL this ConnectionPool Error start to appear and my customer insists on using GCP Cloud SQL service he want everything to be managed by Google (backups, replication ..etc) So Please, I need any Help/ suggestions for this Issue.

Please Note : GCP Cloud SQL using postgresql 11 Implemented on container

Odoo Log :

2019-06-17 09:13:34,962 1335 DEBUG ? odoo.service.server: WorkerCron (1335) polling for jobs
2019-06-17 09:13:34,993 1335 INFO ? odoo.sql_db: ConnectionPool(used=0/count=0/max=5): Closed 1 connections to 'user=odopg password=xxx dbname=test502CE port=5432 sslmode=prefer'
2019-06-17 09:13:34,994 1335 DEBUG ? odoo.service.server: WorkerCron (1335) test502CE time:0.017s mem: 429356.0k -> 429356.0k (diff: 0.0k)
2019-06-17 09:13:34,995 1335 DEBUG ? odoo.service.server: WorkerCron (1335) polling for jobs
2019-06-17 09:13:35,024 1335 INFO ? odoo.sql_db: ConnectionPool(used=0/count=0/max=5): Closed 1 connections to 'user=odopg password=xxx dbname=thimardb port=5432 sslmode=prefer'
2019-06-17 09:13:35,025 1335 DEBUG ? odoo.service.server: WorkerCron (1335) thimardb time:0.016s mem: 429356.0k -> 429356.0k (diff: 0.0k)
2019-06-17 09:13:35,025 1335 DEBUG ? odoo.service.server: WorkerCron (1335) polling for jobs
2019-06-17 09:13:35,055 1335 INFO ? odoo.sql_db: ConnectionPool(used=0/count=0/max=5): Closed 1 connections to 'user=odopg password=xxx dbname=test