backend/app/core/database.py

@@ -1,10 +1,8 @@
-"""SQLite database layer with async CRUD operations.
+"""SQLite database layer with WAL mode and async CRUD operations.
 
 Uses aiosqlite for async access.  ``init_db`` sets critical PRAGMAs
-(busy_timeout, journal_mode, synchronous) *before* creating any tables so
-that concurrent download workers never hit ``SQLITE_BUSY``.  WAL mode is
-preferred on local filesystems; DELETE mode is used automatically when a
-network filesystem (CIFS, NFS) is detected.
+(busy_timeout, WAL, synchronous) *before* creating any tables so that
+concurrent download workers never hit ``SQLITE_BUSY``.
 """
 
 from __future__ import annotations
@@ -92,29 +90,48 @@ async def init_db(db_path: str) -> aiosqlite.Connection:
 
     PRAGMA order matters:
       1. ``busy_timeout`` — prevents immediate ``SQLITE_BUSY`` on lock contention
-      2. ``journal_mode`` — WAL for local filesystems, DELETE for network mounts
-         (CIFS/NFS lack the shared-memory primitives WAL requires)
-      3. ``synchronous=NORMAL`` — safe durability level
+      2. ``journal_mode=WAL`` — enables concurrent readers + single writer
+         (falls back to DELETE on filesystems that lack shared-memory support,
+         e.g. CIFS/SMB mounts)
+      3. ``synchronous=NORMAL`` — safe durability level for WAL mode
 
     Returns the ready-to-use connection.
     """
-    # Detect network filesystem *before* opening the DB so we never attempt
-    # WAL on CIFS/NFS (which creates broken SHM files that persist).
-    use_wal = not _is_network_filesystem(db_path)
-
     db = await aiosqlite.connect(db_path)
     db.row_factory = aiosqlite.Row
 
     # --- PRAGMAs (before any DDL) ---
     await db.execute("PRAGMA busy_timeout = 5000")
 
-    if use_wal:
+    # Attempt WAL mode, then verify it actually works by doing a test write.
+    # On CIFS/NFS/FUSE mounts WAL's shared-memory primitives silently fail
+    # even though the PRAGMA returns "wal".  A concrete write attempt is the
+    # only reliable way to detect this.
     journal_mode = await _try_journal_mode(db, "wal")
-    else:
-        logger.info(
-            "Network filesystem detected for %s — using DELETE journal mode",
-            db_path,
+
+    if journal_mode == "wal":
+        try:
+            # Probe with an actual write — WAL on CIFS explodes here
+            await db.execute(
+                "CREATE TABLE IF NOT EXISTS _wal_probe (_x INTEGER)"
             )
+            await db.execute("DROP TABLE IF EXISTS _wal_probe")
+            await db.commit()
+        except Exception:
+            logger.warning(
+                "WAL mode set but write failed — filesystem likely lacks "
+                "shared-memory support (CIFS/NFS?). Switching to DELETE mode."
+            )
+            # Close and reopen so SQLite drops the broken WAL state
+            await db.close()
+            # Remove stale WAL/SHM files that the broken open left behind
+            import pathlib
+            for suffix in ("-wal", "-shm"):
+                p = pathlib.Path(db_path + suffix)
+                p.unlink(missing_ok=True)
+            db = await aiosqlite.connect(db_path)
+            db.row_factory = aiosqlite.Row
+            await db.execute("PRAGMA busy_timeout = 5000")
             journal_mode = await _try_journal_mode(db, "delete")
 
     logger.info("journal_mode set to %s", journal_mode)
@@ -129,41 +146,6 @@ async def init_db(db_path: str) -> aiosqlite.Connection:
     return db
 
 
-def _is_network_filesystem(db_path: str) -> bool:
-    """Return True if *db_path* resides on a network filesystem (CIFS, NFS, etc.).
-
-    Parses ``/proc/mounts`` (Linux) to find the filesystem type of the
-    longest-prefix mount matching the database directory.  Returns False
-    on non-Linux hosts or if detection fails.
-    """
-    import os
-
-    network_fs_types = {"cifs", "nfs", "nfs4", "smb", "smbfs", "9p", "fuse.sshfs"}
-    try:
-        db_dir = os.path.dirname(os.path.abspath(db_path))
-        with open("/proc/mounts", "r") as f:
-            mounts = f.readlines()
-        best_match = ""
-        best_fstype = ""
-        for line in mounts:
-            parts = line.split()
-            if len(parts) < 3:
-                continue
-            mountpoint, fstype = parts[1], parts[2]
-            if db_dir.startswith(mountpoint) and len(mountpoint) > len(best_match):
-                best_match = mountpoint
-                best_fstype = fstype
-        is_net = best_fstype in network_fs_types
-        if is_net:
-            logger.info(
-                "Detected %s filesystem at %s for database %s",
-                best_fstype, best_match, db_path,
-            )
-        return is_net
-    except Exception:
-        return False
-
-
 async def _try_journal_mode(
     db: aiosqlite.Connection, mode: str,
 ) -> str:
@@ -176,6 +158,15 @@ async def _try_journal_mode(
         logger.warning("PRAGMA journal_mode=%s failed: %s", mode, exc)
         return "error"
 
+    await db.execute("PRAGMA synchronous = NORMAL")
+
+    # --- Schema ---
+    await db.executescript(_TABLES)
+    await db.executescript(_INDEXES)
+    logger.info("Database tables and indexes created at %s", db_path)
+
+    return db
+
 
 # ---------------------------------------------------------------------------
 # CRUD helpers