From d5860a70720eecb7393f5b3183f898a9b14e0e00 Mon Sep 17 00:00:00 2001
From: unknown <liusheng@huawei.com>
Date: Mon, 14 Sep 2015 15:16:52 +0800
Subject: [PATCH] Fix the heavy time cost of event-list

Acorrding the current event-list API, an admin user is allowed to query
all events which have traits.project_id value that match it's own project
OR any event without any project_id trait. In get_events() in
impl_sqlalchemy.py, this current query clause is implemented in a
inefficient way. This change make it more efficient.

Co-Authored-By: gordon chung<gord@live.ca>
Change-Id: I645a7def0552e2574da540e180b4f57d8770e96e
Closes-Bug: #1494440
---
 ceilometer/event/storage/impl_sqlalchemy.py | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/ceilometer/event/storage/impl_sqlalchemy.py b/ceilometer/event/storage/impl_sqlalchemy.py
index e0497b42..46368af3 100644
--- a/ceilometer/event/storage/impl_sqlalchemy.py
+++ b/ceilometer/event/storage/impl_sqlalchemy.py
@@ -266,14 +266,18 @@ class Connection(base.Connection):
                 query = query.join(trait_subq,
                                    trait_subq.c.ev_id == models.Event.id)
             if event_filter.admin_proj:
-                admin_q = session.query(models.TraitText).filter(
+                no_proj_q = session.query(models.TraitText.event_id).filter(
                     models.TraitText.key == 'project_id')
-                query = query.filter(sa.or_(~sa.exists().where(
-                    models.Event.id == admin_q.subquery().c.event_id),
-                    sa.and_(
+                admin_q = (session.query(models.TraitText.event_id).filter(
+                    ~sa.exists().where(models.TraitText.event_id ==
+                                       no_proj_q.subquery().c.event_id)).union(
+                    session.query(models.TraitText.event_id).filter(sa.and_(
                         models.TraitText.key == 'project_id',
                         models.TraitText.value == event_filter.admin_proj,
-                        models.Event.id == models.TraitText.event_id)))
+                        models.Event.id == models.TraitText.event_id))))
+                query = query.filter(sa.exists().where(
+                    models.Event.id ==
+                    admin_q.subquery().c.trait_text_event_id))
             if event_filter_conditions:
                 query = query.filter(sa.and_(*event_filter_conditions))
 
@@ -283,7 +287,7 @@ class Connection(base.Connection):
             for (id_, generated, message_id,
                  desc, raw) in query.add_columns(
                      models.Event.generated, models.Event.message_id,
-                     models.EventType.desc, models.Event.raw).distinct().all():
+                     models.EventType.desc, models.Event.raw).all():
                 event_list[id_] = api_models.Event(message_id, desc,
                                                    generated, [], raw)
             # Query all traits related to events.