core: Wrap Connection::query_only with AtomicBool

core/incremental/compiler.rs

@@ -1506,7 +1506,7 @@ impl DbspCompiler {
         let io = Arc::new(MemoryIO::new());
         let db = Database::open_file(io, ":memory:", false, false)?;
         let internal_conn = db.connect()?;
-        internal_conn.query_only.set(true);
+        internal_conn.set_query_only(true);
         internal_conn.auto_commit.store(false, Ordering::SeqCst);
 
         // Create temporary symbol table

core/incremental/project_operator.rs

@@ -62,7 +62,7 @@ impl ProjectOperator {
         )?;
         let internal_conn = db.connect()?;
         // Set to read-only mode and disable auto-commit since we're only evaluating expressions
-        internal_conn.query_only.set(true);
+        internal_conn.set_query_only(true);
         internal_conn.auto_commit.store(false, Ordering::SeqCst);
 
         // Create ProjectColumn structs from compiled expressions

core/lib.rs

@@ -513,7 +513,7 @@ impl Database {
             capture_data_changes: RwLock::new(CaptureDataChangesMode::Off),
             closed: AtomicBool::new(false),
             attached_databases: RefCell::new(DatabaseCatalog::new()),
-            query_only: Cell::new(false),
+            query_only: AtomicBool::new(false),
             mv_tx: Cell::new(None),
             view_transaction_states: AllViewsTxState::new(),
             metrics: RefCell::new(ConnectionMetrics::new()),
@@ -1003,7 +1003,7 @@ pub struct Connection {
     closed: AtomicBool,
     /// Attached databases
     attached_databases: RefCell<DatabaseCatalog>,
-    query_only: Cell<bool>,
+    query_only: AtomicBool,
     pub(crate) mv_tx: Cell<Option<(crate::mvcc::database::TxID, TransactionMode)>>,
 
     /// Per-connection view transaction states for uncommitted changes. This represents
@@ -1711,6 +1711,10 @@ impl Connection {
         self.closed.load(Ordering::SeqCst)
     }
 
+    pub fn is_query_only(&self) -> bool {
+        self.query_only.load(Ordering::SeqCst)
+    }
+
     pub fn get_database_canonical_path(&self) -> String {
         if self.db.path == ":memory:" {
             // For in-memory databases, SQLite shows empty string
@@ -2120,11 +2124,11 @@ impl Connection {
     }
 
     pub fn get_query_only(&self) -> bool {
-        self.query_only.get()
+        self.is_query_only()
     }
 
     pub fn set_query_only(&self, value: bool) {
-        self.query_only.set(value);
+        self.query_only.store(value, Ordering::SeqCst);
     }
 
     pub fn get_sync_mode(&self) -> SyncMode {