[IMP] core: --db_maxconn_gevent

The Gevent worker has specifc needs in term of maximum concurrent
connections to the database and those needs are not compatible with the
default limit that is primerly set for http workers.

This PR makes it possible to supply a configuration dedicated to the
gevent worker.

task-id-3193565
task-id-2146565

closes odoo/odoo#125190

Signed-off-by: Julien Castiaux (juc) <juc@odoo.com>

odoo/sql_db.py

@@ -26,6 +26,7 @@ from psycopg2.pool import PoolError
 from psycopg2.sql import SQL, Identifier
 from werkzeug import urls
 
+import odoo
 from . import tools
 from .tools.func import frame_codeinfo, locked
 
@@ -764,7 +765,10 @@ _Pool = None
 def db_connect(to, allow_uri=False):
     global _Pool
     if _Pool is None:
-        _Pool = ConnectionPool(int(tools.config['db_maxconn']))
+        _Pool = ConnectionPool(int(
+            odoo.evented and tools.config['db_maxconn_gevent']
+            or tools.config['db_maxconn']
+        ))
 
     db, info = connection_info_for(to)
     if not allow_uri and db != to:

odoo/tools/config.py

@@ -259,6 +259,8 @@ class configmanager(object):
                          help="specify the database ssl connection mode (see PostgreSQL documentation)")
         group.add_option("--db_maxconn", dest="db_maxconn", type='int', my_default=64,
                          help="specify the maximum number of physical connections to PostgreSQL")
+        group.add_option("--db_maxconn_gevent", dest="db_maxconn_gevent", type='int', my_default=False,
+                         help="specify the maximum number of physical connections to PostgreSQL specifically for the gevent worker")
         group.add_option("--db-template", dest="db_template", my_default="template0",
                          help="specify a custom database template to create a new database")
         parser.add_option_group(group)
@@ -448,7 +450,7 @@ class configmanager(object):
                 'db_port', 'db_template', 'logfile', 'pidfile', 'smtp_port',
                 'email_from', 'smtp_server', 'smtp_user', 'smtp_password', 'from_filter',
                 'smtp_ssl_certificate_filename', 'smtp_ssl_private_key_filename',
-                'db_maxconn', 'import_partial', 'addons_path', 'upgrade_path',
+                'db_maxconn', 'db_maxconn_gevent', 'import_partial', 'addons_path', 'upgrade_path',
                 'syslog', 'without_demo', 'screencasts', 'screenshots',
                 'dbfilter', 'log_level', 'log_db',
                 'log_db_level', 'geoip_city_db', 'geoip_country_db', 'dev_mode',