fixed CPU logging from db

db_async.py

@@ -143,13 +143,17 @@ async def init_db_async():
             ))
     except Exception as e:
         print(f"Warning: failed to create composite index ix_telemetry_events_char_ts: {e}")
-    # Disable parallel workers at the system level to avoid OOMs from large parallel scans
+    # Add retention and compression policies on the hypertable
     try:
-        # Apply settings outside transaction for ALTER SYSTEM
-        conn2 = engine.connect().execution_options(isolation_level="AUTOCOMMIT")
-        conn2.execute(text("ALTER SYSTEM SET max_parallel_workers_per_gather = 0"))
-        conn2.execute(text("ALTER SYSTEM SET max_parallel_workers = 0"))
-        conn2.execute(text("SELECT pg_reload_conf()"))
-        conn2.close()
+        with engine.connect().execution_options(isolation_level="AUTOCOMMIT") as conn:
+            # Retain only recent data (default 7 days or override via DB_RETENTION_DAYS)
+            days = int(os.getenv('DB_RETENTION_DAYS', '7'))
+            conn.execute(text(
+                f"SELECT add_retention_policy('telemetry_events', INTERVAL '{days} days')"
+            ))
+            # Compress chunks older than 1 day
+            conn.execute(text(
+                "SELECT add_compression_policy('telemetry_events', INTERVAL '1 day')"
+            ))
     except Exception as e:
-        print(f"Warning: failed to disable parallel workers: {e}")
+        print(f"Warning: failed to set retention/compression policies: {e}")