From 13ff10d8f13d98c797bca387a79caa2f8d0a0ed6 Mon Sep 17 00:00:00 2001
From: Nicolas Seinlet <nse@openerp.com>
Date: Mon, 10 May 2021 13:27:48 +0000
Subject: [PATCH] [IMP] mail: better join improve query execution time

- using join on required fields ease PostgreSQL planner guessing
- skip useless join, the fastest code is the not executed one
- skip dynamic `or` insertion and replace with a union all in CTE
- replacing `where exists` with a join is then possible
- a bit of alignment

from some s to some ms execution time.

Submit an "Apply for a job" on website , goes from
`"POST /website_form/hr.applicant HTTP/1.0" 200 - 182 2.649 0.106`
without this patch, to
`"POST /website_form/hr.applicant HTTP/1.0" 200 - 185 0.492 0.107`
when this patch is applied

closes odoo/odoo#71028

X-original-commit: 783280375ff04955978a14f007f96d6c4d7443b1
Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>
---
 addons/mail/models/mail_followers.py | 52 ++++++++++++++++------------
 1 file changed, 29 insertions(+), 23 deletions(-)

diff --git a/addons/mail/models/mail_followers.py b/addons/mail/models/mail_followers.py
index 9dc23cb713e..8ad6b09a201 100644
--- a/addons/mail/models/mail_followers.py
+++ b/addons/mail/models/mail_followers.py
@@ -105,33 +105,39 @@ class Followers(models.Model):
             query = """
 SELECT DISTINCT ON (pid) * FROM (
     WITH sub_followers AS (
-        SELECT fol.id, fol.partner_id, subtype.internal
-        FROM mail_followers fol
-            RIGHT JOIN mail_followers_mail_message_subtype_rel subrel
-            ON subrel.mail_followers_id = fol.id
-            RIGHT JOIN mail_message_subtype subtype
-            ON subtype.id = subrel.mail_message_subtype_id
-        WHERE subrel.mail_message_subtype_id = %%s AND fol.res_model = %%s AND fol.res_id IN %%s
+        SELECT fol.partner_id,
+               coalesce(subtype.internal, false) as internal
+          FROM mail_followers fol
+          JOIN mail_followers_mail_message_subtype_rel subrel ON subrel.mail_followers_id = fol.id
+          JOIN mail_message_subtype subtype ON subtype.id = subrel.mail_message_subtype_id
+         WHERE subrel.mail_message_subtype_id = %s
+           AND fol.res_model = %s
+           AND fol.res_id IN %s
+
+     UNION ALL
+
+        SELECT id,
+               FALSE
+          FROM res_partner
+         WHERE id=ANY(%s)
     )
     SELECT partner.id as pid,
-            partner.active as active, partner.partner_share as pshare,
-            users.notification_type AS notif, array_agg(groups.id) AS groups
-        FROM res_partner partner
-        LEFT JOIN res_users users ON users.partner_id = partner.id AND users.active
-        LEFT JOIN res_groups_users_rel groups_rel ON groups_rel.uid = users.id
-        LEFT JOIN res_groups groups ON groups.id = groups_rel.gid
-        WHERE EXISTS (
-            SELECT partner_id FROM sub_followers
-            WHERE sub_followers.partner_id = partner.id
-                AND (coalesce(sub_followers.internal, false) <> TRUE OR coalesce(partner.partner_share, false) <> TRUE)
-        ) %s
-        GROUP BY partner.id, users.notification_type
+           partner.active as active,
+           partner.partner_share as pshare,
+           users.notification_type AS notif,
+           array_agg(groups_rel.gid) AS groups
+      FROM res_partner partner
+ LEFT JOIN res_users users ON users.partner_id = partner.id
+                          AND users.active
+ LEFT JOIN res_groups_users_rel groups_rel ON groups_rel.uid = users.id
+      JOIN sub_followers ON sub_followers.partner_id = partner.id
+                        AND NOT (sub_followers.internal AND partner.partner_share)
+        GROUP BY partner.id,
+                 users.notification_type
 ) AS x
 ORDER BY pid, notif
-""" % ('OR partner.id IN %s' if pids else '')
-            params = [subtype_id, records._name, tuple(records.ids)]
-            if pids:
-                params.append(tuple(pids))
+"""
+            params = [subtype_id, records._name, tuple(records.ids), list(pids) or []]
             self.env.cr.execute(query, tuple(params))
             res = self.env.cr.fetchall()
         elif pids: