perf: eagerly load auxiliary data

app/models/attachment.py

@@ -18,7 +18,8 @@ class Attachment(db.Model):
     # The comment linked with
     comment_id = db.Column(db.Integer, db.ForeignKey('comment.id'),
         nullable=False, index=True)
-    comment = db.relationship('Comment', backref=backref('attachments'))
+    comment = db.relationship('Comment', back_populates='attachments',
+        foreign_keys=comment_id)
 
     # The size of the file
     size = db.Column(db.Integer)

app/models/comment.py

@@ -20,7 +20,8 @@ class Comment(Post):
         backref=backref('comments', lazy='dynamic'),
         foreign_keys=thread_id)
 
-    # attachments (relation from Attachment)
+    attachments = db.relationship('Attachment', back_populates='comment',
+        lazy='joined')
 
     @property
     def is_top_comment(self):

app/models/priv.py

@@ -17,7 +17,7 @@ class SpecialPrivilege(db.Model):
 
     # Member that is granted the privilege
     member_id = db.Column(db.Integer, db.ForeignKey('member.id'), index=True)
-    member = db.relationship('Member', backref="special_privs",
+    member = db.relationship('Member', back_populates="special_privs",
         foreign_keys=member_id)
     # Privilege name
     priv = db.Column(db.String(64))
@@ -45,10 +45,9 @@ class Group(db.Model):
     description = db.Column(db.UnicodeText)
     # List of members (lambda delays evaluation)
     members = db.relationship('Member', secondary=lambda: GroupMember,
-        back_populates='groups')
-
-    # Other fields populated automatically through relations:
-    #     <privileges> list of privileges
+        back_populates='groups', lazy='joined')
+    # List of privileges
+    privileges = db.relationship('GroupPrivilege', back_populates='group')
 
     def __init__(self, name, css, descr):
         self.name = name
@@ -87,7 +86,7 @@ class GroupPrivilege(db.Model):
     id = db.Column(db.Integer, primary_key=True)
 
     group_id = db.Column(db.Integer, db.ForeignKey('group.id'))
-    group = db.relationship('Group', backref='privileges',
+    group = db.relationship('Group', back_populates='privileges',
         foreign_keys=group_id)
 
     priv = db.Column(db.String(64))

app/models/user.py

@@ -92,7 +92,7 @@ class Member(User):
 
     # Groups and related privileges
     groups = db.relationship('Group', secondary=GroupMember,
-        back_populates='members')
+        back_populates='members', lazy='joined')
 
     # Personal information, all optional
     bio = db.Column(db.UnicodeText)
@@ -112,6 +112,15 @@ class Member(User):
     trophies = db.relationship('Trophy', secondary=TrophyMember,
         back_populates='owners')
 
+    # Specially-offered privileges (use self.special_privileges())
+    special_privs = db.relationship('SpecialPrivilege',
+        back_populates='member', lazy='joined')
+
+
+    # Other fields populated automatically through relations:
+    #   <notifications>   List of unseen notifications (of type Notification)
+    #   <polls>           Polls created by the member (of class Poll)
+
     # Access to polymorphic posts
     # TODO: Check that the query uses the double index on Post.{author_id,type}
     def comments(self):
@@ -138,11 +147,6 @@ class Member(User):
         return int(level), int(level * 100) % 100
 
 
-    # Other fields populated automatically through relations:
-    #   <special_privs>   List of special privileges
-    #   <notifications>   List of unseen notifications (of type Notification)
-    #   <polls>           Polls created by the member (of class Poll)
-
     def __init__(self, name, email, password):
         """Register a new user."""
         self.name = name