From c05706b9529b079423dccfbcaeaaf535b98e583b Mon Sep 17 00:00:00 2001
From: Vaclav Lunak <v.lunak@gmail.com>
Date: Wed, 7 Feb 2024 12:13:02 +0100
Subject: [PATCH] update SQL queries to improve performance, fix alembic
 automigrations

---
 alembic/env.py       |  4 ++--
 src/cr/service.py    |  2 +-
 src/diffs/service.py |  4 ++--
 src/models.py        | 15 +++++++++++++++
 src/mtr/service.py   |  2 +-
 5 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/alembic/env.py b/alembic/env.py
index b3b9f37..6ea6d47 100644
--- a/alembic/env.py
+++ b/alembic/env.py
@@ -4,7 +4,7 @@
 from sqlalchemy import engine_from_config, pool
 
 from alembic import context
-from models import Base
+from src.models import get_full_base
 
 # this is the Alembic Config object, which provides
 # access to the values within the .ini file in use.
@@ -19,7 +19,7 @@
 # for 'autogenerate' support
 # from myapp import mymodel
 # target_metadata = mymodel.Base.metadata
-target_metadata = Base.metadata
+target_metadata = get_full_base().metadata
 
 # other values from the config, defined by the needs of env.py,
 # can be acquired:
diff --git a/src/cr/service.py b/src/cr/service.py
index 7da9abe..b185d5c 100644
--- a/src/cr/service.py
+++ b/src/cr/service.py
@@ -9,7 +9,7 @@
 
 
 def get_latest_cr(db: Session) -> Cr:
-    stmt = select(Cr).order_by(Cr.creation_day.desc())
+    stmt = select(Cr).order_by(Cr.creation_day.desc()).limit(1)
     result = db.execute(stmt).scalars().first()
     return result
 
diff --git a/src/diffs/service.py b/src/diffs/service.py
index 226a311..707026d 100644
--- a/src/diffs/service.py
+++ b/src/diffs/service.py
@@ -18,9 +18,9 @@ def get_cr_diff(db: Session, old_code: str | None, new_code: str | None) -> CrDi
         stmt = stmt.order_by(CrDiff.creation_day.desc()).limit(1)
     else:
         if old_code:
-            stmt = stmt.where(src.set_code == old_code)
+            stmt = stmt.where(src.set_code == old_code).limit(1)
         if new_code:
-            stmt = stmt.where(dst.set_code == new_code)
+            stmt = stmt.where(dst.set_code == new_code).limit(1)
 
     return db.execute(stmt).scalars().first()
 
diff --git a/src/models.py b/src/models.py
index 59be703..812915e 100644
--- a/src/models.py
+++ b/src/models.py
@@ -1,3 +1,18 @@
 from sqlalchemy.orm import declarative_base
 
 Base = declarative_base()
+
+
+# noinspection PyUnresolvedReferences
+
+
+def get_full_base():
+    """Imports all database models before returning the Base object. Used for alembic migrations"""
+
+    import src.cr.models  # noqa: F401
+    import src.diffs.models  # noqa: F401
+    import src.ipg.models  # noqa: F401
+    import src.link.models  # noqa: F401
+    import src.mtr.models  # noqa: F401
+
+    return Base
diff --git a/src/mtr/service.py b/src/mtr/service.py
index a4b9a6c..3c9395b 100644
--- a/src/mtr/service.py
+++ b/src/mtr/service.py
@@ -7,7 +7,7 @@
 
 
 def get_current_mtr(db: Session) -> Mtr:
-    stmt = select(Mtr).order_by(Mtr.creation_day.desc())
+    stmt = select(Mtr).order_by(Mtr.creation_day.desc()).limit(1)
     result = db.execute(stmt).scalars().first()
     return result