Aug 27 - Add MySQL optimize and security check

config.py

@@ -32,6 +32,34 @@ class Config:
     SQLALCHEMY_TRACK_MODIFICATIONS = False
     SQLALCHEMY_ECHO = False
 
+    # ── Connection pool ─────────────────────────────────────────────────────
+    # Without these the pool runs on library defaults, which is where the
+    # intermittent OperationalError 2006 ("MySQL server has gone away") comes
+    # from: MySQL closes a connection after wait_timeout (8h by default) and
+    # SQLAlchemy hands the dead socket to the next request.
+    #
+    #   pool_pre_ping  — cheap liveness check before a connection is handed out;
+    #                    a dead one is discarded and replaced transparently.
+    #   pool_recycle   — retire connections after 30 min, well under any sane
+    #                    wait_timeout, so they are never the stale ones.
+    #   pool_size /    — Gunicorn runs sync workers (cpu*2+1), and each worker
+    #   max_overflow     holds its OWN pool. Library defaults (5 + 10) mean a
+    #                    9-worker box can open 135 connections against a
+    #                    max_connections of 151. A sync worker serves one
+    #                    request at a time, so it needs one connection in
+    #                    steady state; the small overflow is headroom for
+    #                    background email/notification threads.
+    #
+    # Tune with scripts/db_health.py, which cross-checks these against the
+    # server's live max_connections and wait_timeout.
+    SQLALCHEMY_ENGINE_OPTIONS = {
+        'pool_pre_ping': True,
+        'pool_recycle':  int(os.environ.get('DB_POOL_RECYCLE', '1800')),
+        'pool_size':     int(os.environ.get('DB_POOL_SIZE', '5')),
+        'max_overflow':  int(os.environ.get('DB_MAX_OVERFLOW', '5')),
+        'pool_timeout':  30,
+    }
+
     # ── File uploads ────────────────────────────────────────────────────────
     UPLOAD_FOLDER = os.path.join(basedir, 'app/static/uploads')
     MAX_CONTENT_LENGTH = 50 * 1024 * 1024   # 50 MB