chore: remove SQLite entirely, PostgreSQL only

SQLite was never used in production (Docker Compose always sets
DATABASE_URL to postgresql+asyncpg://...) but the fallback kept
creating confusing stock_oracle.db files locally.

- config.py: default DATABASE_URL fallback → PostgreSQL (localhost:15433)
- database.py: remove _is_sqlite conditional branch and NullPool import
- error_logs.py: replace strftime/dialect-check with pg to_char()
- request_logs.py: replace strftime with pg to_char()
- feature_builder.py: remove _ensure_utc() helper and all call sites
- overlay_pipeline.py: remove naive-datetime workaround for is_stale()
- requirements-api.txt / requirements-test.txt: drop aiosqlite
- stock_oracle.db: deleted

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/api/v1/endpoints/error_logs.py

@@ -266,12 +266,7 @@ async def get_error_stats(
     # Get hourly trend for last 24 hours if within range
     hourly_trend = {}
     if (end_date - start_date).days <= 1:
-        # Dialect-aware date formatting
-        dialect_name = db.bind.dialect.name if db.bind else "sqlite"
-        if dialect_name == "postgresql":
         hour_expr = func.to_char(ErrorLog.created_at, 'YYYY-MM-DD HH24:00').label('hour')
-        else:
-            hour_expr = func.strftime('%Y-%m-%d %H:00', ErrorLog.created_at).label('hour')
         hourly_result = await db.execute(
             select(
                 hour_expr,

app/api/v1/endpoints/request_logs.py

@@ -262,10 +262,9 @@ async def get_request_stats(
     # Get hourly trend for last 24 hours if within range
     hourly_trend = {}
     if (end_date - start_date).days <= 1:
-        # SQLite specific date formatting
         hourly_result = await db.execute(
             select(
-                func.strftime('%Y-%m-%d %H:00', RequestLog.created_at).label('hour'),
+                func.to_char(RequestLog.created_at, 'YYYY-MM-DD HH24:00').label('hour'),
                 func.count().label('count')
             ).where(date_filter)
             .group_by('hour')

app/core/config.py

@@ -38,7 +38,7 @@ class Settings(BaseSettings):
     # Database
     DATABASE_URL: str = os.getenv(
         "DATABASE_URL",
-        "sqlite+aiosqlite:///./stock_oracle.db"
+        "postgresql+asyncpg://stockoracle:stockoracle2024@localhost:15433/stock_oracle"
     )
     DATABASE_ECHO: bool = False
     

app/core/database.py

@@ -4,20 +4,9 @@ Database configuration and session management
 
 from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine
 from sqlalchemy.orm import sessionmaker, declarative_base
-from sqlalchemy.pool import NullPool
-from app.core.config import settings
 
-# Conditional engine settings based on database type
+from app.core.config import settings
-_is_sqlite = settings.DATABASE_URL.startswith("sqlite")
 
-if _is_sqlite:
-    engine = create_async_engine(
-        settings.DATABASE_URL,
-        echo=settings.DATABASE_ECHO,
-        future=True,
-        poolclass=NullPool,
-    )
-else:
 engine = create_async_engine(
     settings.DATABASE_URL,
     echo=settings.DATABASE_ECHO,

app/services/overlay/feature_builder.py

@@ -29,14 +29,6 @@ def winsorize(value: float, lower: float = WINSOR_LOWER, upper: float = WINSOR_U
     return max(lower, min(upper, value))
 
 
-def _ensure_utc(dt) -> datetime:
-    """Ensure a datetime is UTC-aware (SQLite returns naive datetimes)."""
-    if dt is None:
-        return dt
-    if isinstance(dt, datetime) and dt.tzinfo is None:
-        return dt.replace(tzinfo=timezone.utc)
-    return dt
-
 
 def compute_zscore(value: float, values: List[float]) -> Optional[float]:
     """Compute z-score of *value* within *values* (requires ≥2 data points)."""
@@ -95,8 +87,8 @@ class FeatureBuilder:
 
         # Filter by symbol
         sym_rows_hist = [r for r in all_rows if symbol in (r.matched_symbols or [])]
-        sym_rows_24h = [r for r in sym_rows_hist if _ensure_utc(r.published_at) >= cutoff_24h]
+        sym_rows_24h = [r for r in sym_rows_hist if r.published_at >= cutoff_24h]
-        sym_rows_6h = [r for r in sym_rows_24h if _ensure_utc(r.published_at) >= cutoff_6h]
+        sym_rows_6h = [r for r in sym_rows_24h if r.published_at >= cutoff_6h]
 
         headline_count_24h = len(sym_rows_24h)
         headline_count_6h = len(sym_rows_6h)
@@ -144,7 +136,7 @@ class FeatureBuilder:
         )
         all_rows = result.fetchall()
         sym_rows = [r for r in all_rows if symbol in (r.matched_symbols or [])]
-        sym_rows_24h = [r for r in sym_rows if _ensure_utc(r.published_at) >= cutoff_24h]
+        sym_rows_24h = [r for r in sym_rows if r.published_at >= cutoff_24h]
 
         mentions_24h = len(sym_rows_24h)
         weighted_views_24h = sum(r.view_count * r.channel_weight for r in sym_rows_24h)
@@ -195,7 +187,7 @@ class FeatureBuilder:
         views_1d = rows[0].views if rows else None
 
         # 7-day average
-        rows_7d = [r for r in rows if _ensure_utc(r.date) >= cutoff_7d]
+        rows_7d = [r for r in rows if r.date >= cutoff_7d]
         views_7d_avg = sum(r.views for r in rows_7d) / len(rows_7d) if rows_7d else None
 
         # Historical z-score

app/services/overlay/overlay_pipeline.py

@@ -181,11 +181,7 @@ class OverlayPipeline:
         """Return True if the record is missing or older than FEATURE_STALE_HOURS."""
         if record is None:
             return True
-        # SQLite returns naive datetimes; ensure UTC-aware for comparison
+        age = datetime.now(timezone.utc) - record.as_of_ts
-        as_of = record.as_of_ts
-        if as_of.tzinfo is None:
-            as_of = as_of.replace(tzinfo=timezone.utc)
-        age = datetime.now(timezone.utc) - as_of
         return age.total_seconds() > FEATURE_STALE_HOURS * 3600
 
     # ------------------------------------------------------------------

requirements-api.txt

@@ -3,7 +3,6 @@ uvicorn[standard]>=0.24.0
 sqlalchemy>=2.0.0,<3.0.0
 alembic>=1.12.0
 asyncpg>=0.29.0
-aiosqlite>=0.19.0
 greenlet>=2.0.0
 pydantic>=2.0.0,<3.0.0
 pydantic-settings>=2.0.0

requirements-test.txt

@@ -5,4 +5,3 @@ pytest-cov>=4.1.0
 httpx>=0.25.0
 faker>=20.0.0
 pydantic-settings>=2.0.0
-aiosqlite>=0.19.0