db: enable WAL mode and other PRAGMA stmts for SQLite to avoid db locking during concurrent writes (PROJQUAY-8758) (#4193)

* ADD PRAGMA statements for SQLITE to avoid database locking

* Fix formating

data/database.py

@@ -453,7 +453,12 @@ def _db_from_url(
 
     drivers = _SCHEME_DRIVERS[parsed_url.drivername]
     driver = drivers.driver
-    if allow_pooling and os.getenv("DB_CONNECTION_POOLING", "false").lower() == "true":
+    # Skip connection pooling for SQLite - use single connection
+    if (
+        allow_pooling
+        and os.getenv("DB_CONNECTION_POOLING", "false").lower() == "true"
+        and parsed_url.drivername != "sqlite"
+    ):
         driver = drivers.pooled_driver
         db_kwargs["stale_timeout"] = db_kwargs.get("stale_timeout", None)
         db_kwargs["max_connections"] = db_kwargs.get("max_connections", None)
@@ -495,6 +500,56 @@ def _db_from_url(
     # https://github.com/coleifer/peewee/commit/36bd887ac07647c60dfebe610b34efabec675706
     if parsed_url.drivername.find("mysql") >= 0:
         created.compound_select_parentheses = 0
+
+    # Configure SQLite-specific PRAGMA statements for database locking optimization
+    if parsed_url.drivername == "sqlite":
+
+        def _configure_sqlite_pragmas(db_instance):
+            """Configure SQLite-specific PRAGMA statements to prevent database locks."""
+            try:
+                # Set busy timeout to 10 seconds to handle concurrent access
+                db_instance.execute_sql("PRAGMA busy_timeout = 10000;")
+                db_instance.execute_sql("PRAGMA journal_mode = WAL;")
+                db_instance.execute_sql(
+                    "PRAGMA wal_autocheckpoint = 1000;"
+                )  # Set WAL checkpointing to 1000 pages
+                db_instance.execute_sql(
+                    "PRAGMA synchronous = NORMAL;"
+                )  # Balance durability/performance
+
+                # Verify the PRAGMA settings were applied
+                busy_timeout_result = db_instance.execute_sql("PRAGMA busy_timeout;")
+                journal_mode_result = db_instance.execute_sql("PRAGMA journal_mode;")
+
+                # Extract actual values from results
+                busy_timeout_value = (
+                    busy_timeout_result.fetchone()[0] if busy_timeout_result else "unknown"
+                )
+                journal_mode_value = (
+                    journal_mode_result.fetchone()[0] if journal_mode_result else "unknown"
+                )
+
+                logger.info(
+                    "Applied SQLite PRAGMA statements for database: %s - busy_timeout: %s, journal_mode: %s",
+                    parsed_url.database,
+                    busy_timeout_value,
+                    journal_mode_value,
+                )
+            except Exception as e:
+                logger.warning(
+                    "Failed to configure SQLite optimizations for %s: %s", parsed_url.database, e
+                )
+
+        # Override connect method to apply PRAGMA statements on each connection
+        original_connect = created.connect
+
+        def enhanced_connect(reuse_if_open=False):
+            result = original_connect(reuse_if_open)
+            _configure_sqlite_pragmas(created)
+            return result
+
+        created.connect = enhanced_connect
+
     return created