[frontend] speed up querying for recent builds

frontend/coprs_frontend/alembic/versions/3a9905ed8ffd_add_index_to_build_chroot_ended_on_.py

@@ -0,0 +1,26 @@
+"""add index to build_chroot.ended_on column
+
+Revision ID: 3a9905ed8ffd
+Revises: 3341bf554454
+Create Date: 2016-09-27 11:57:50.075139
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '3a9905ed8ffd'
+down_revision = '3341bf554454'
+
+from alembic import op
+import sqlalchemy as sa
+
+
+def upgrade():
+    ### commands auto generated by Alembic - please adjust! ###
+    op.create_index(op.f('ix_build_chroot_ended_on'), 'build_chroot', ['ended_on'], unique=False)
+    ### end Alembic commands ###
+
+
+def downgrade():
+    ### commands auto generated by Alembic - please adjust! ###
+    op.drop_index('ix_build_chroot_ended_on', table_name='build_chroot')
+    ### end Alembic commands ###

frontend/coprs_frontend/coprs/logic/builds_logic.py

@@ -57,9 +57,12 @@ def get_recent_tasks(cls, user=None, limit=None):
         if not limit:
             limit = 100
 
-        query = models.Build.query \
-            .join(models.BuildChroot).filter(models.BuildChroot.ended_on.isnot(None)) \
-            .order_by(models.BuildChroot.ended_on.desc())
+        query = models.Build.query.join(
+            models.BuildChroot.query\
+                .filter(models.BuildChroot.ended_on.isnot(None))\
+                .order_by(models.BuildChroot.ended_on.desc())\
+                .limit(limit).subquery()
+        )
 
         if user is not None:
             query = query.filter(models.Build.user_id == user.id)

frontend/coprs_frontend/coprs/models.py

@@ -885,7 +885,7 @@ class BuildChroot(db.Model, helpers.Serializer):
     status = db.Column(db.Integer, default=StatusEnum("importing"))
 
     started_on = db.Column(db.Integer)
-    ended_on = db.Column(db.Integer)
+    ended_on = db.Column(db.Integer, index=True)
 
     last_deferred = db.Column(db.Integer)