# HG changeset patch
# User Mads Kiilerich <madski@unity3d.com>
# Date 2015-01-06 00:54:36
# Node ID ad374c1716566be93bc7f224bcbc24c56bd0538a
# Parent  d8ad71e7b90d9047b01ae9accb50b9eb59f5534d

comments: introduce lazy join of ChangesetStatus on ChangesetComment

99% of all uses of ChangesetComment will also need the optional corresponding
ChangesetStatus (if any) on the status_change relationship. Fetching it on
demand gives a lot of roundtrips and might be slow ... but adding explicit bulk
queries everywhere do not seem feasible. Adding lazy=joined in the data model
seems like the best solution.

Loading a pull request with 10 comments on a slow repo goes from 3.5 s to
2.7 s.

diff --git a/kallithea/model/db.py b/kallithea/model/db.py
--- a/kallithea/model/db.py
+++ b/kallithea/model/db.py
@@ -2149,7 +2149,10 @@ class ChangesetComment(Base, BaseModel):
 
     author = relationship('User', lazy='joined')
     repo = relationship('Repository')
-    status_change = relationship('ChangesetStatus', cascade="all, delete-orphan")
+    # status_change is frequently used directly in templates - make it a lazy
+    # join to avoid fetching each related ChangesetStatus on demand.
+    # There will only be one ChangesetStatus referencing each comment so the join will not explode.
+    status_change = relationship('ChangesetStatus', cascade="all, delete-orphan", lazy='joined')
     pull_request = relationship('PullRequest')
 
     @classmethod