indices indexes

migrations/versions/f63bf9e73bc9_replace_index_on_posts_author_id_with_.py

@@ -0,0 +1,26 @@
+"""replace index on posts.author_id with composite index on author_id and created_at
+
+Revision ID: f63bf9e73bc9
+Revises: e769c033e5c9
+Create Date: 2017-08-15 23:55:46.945437
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'f63bf9e73bc9'
+down_revision = 'e769c033e5c9'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.create_index('ix_posts_author_id_created_at', 'posts', ['author_id', 'created_at'], unique=False)
+    op.drop_index('ix_posts_author_id', table_name='posts')
+
+
+def downgrade():
+    op.create_index('ix_posts_author_id', 'posts', ['author_id'], unique=False)
+    op.drop_index('ix_posts_author_id_created_at', table_name='posts')

model.py

@@ -101,7 +101,7 @@ class Account(TimestampMixin, RemoteIDMixin):
         """
         latest_n_posts = Post.query.with_parent(self).order_by(db.desc(Post.created_at)).limit(self.policy_keep_latest)
         query = Post.query.with_parent(self).\
-            filter(Post.created_at + self.policy_keep_younger <= db.func.now()).\
+            filter(Post.created_at <= db.func.now() - self.policy_keep_younger).\
             except_(latest_n_posts)
         if(self.policy_keep_favourites):
             query = query.filter_by(favourite = False)
@@ -147,7 +147,7 @@ class Post(db.Model, TimestampMixin, RemoteIDMixin):
     id = db.Column(db.String, primary_key=True)
     body = db.Column(db.String)
 
-    author_id = db.Column(db.String, db.ForeignKey('accounts.id', ondelete='CASCADE', onupdate='CASCADE'), nullable=False, index=True)
+    author_id = db.Column(db.String, db.ForeignKey('accounts.id', ondelete='CASCADE', onupdate='CASCADE'), nullable=False)
     author = db.relationship(Account,
             backref=db.backref('posts', order_by=lambda: db.desc(Post.created_at)))
 
@@ -162,6 +162,8 @@ class Post(db.Model, TimestampMixin, RemoteIDMixin):
     def __repr__(self):
         return '<Post ({}, "{}", Author: {})>'.format(self.id, self.snippet(), self.author_id)
 
+db.Index('ix_posts_author_id_created_at', Post.author_id, Post.created_at)
+
 class TwitterArchive(db.Model, TimestampMixin):
     __tablename__ = 'twitter_archives'