Function _execute_readonly_query

web/pgadmin/llm/tools/database.py:238–309

Execute a query in a read-only transaction. The query is wrapped in a read-only transaction to ensure no data modifications can occur. Args: conn: Database connection query: SQL query to execute Returns: Dictionary with 'columns' and 'rows' keys R

(conn, query: str)

def _execute_readonly_query(conn, query: str) -> dict:
    """
    Execute a query in a read-only transaction.

    The query is wrapped in a read-only transaction to ensure
    no data modifications can occur.

    Args:
        conn: Database connection
        query: SQL query to execute

    Returns:
        Dictionary with 'columns' and 'rows' keys

    Raises:
        DatabaseToolError: If query execution fails
    """
    # Set the transaction to read-only, execute, then rollback.
    # This ensures even if the query tries to modify data, it will fail.
    try:
        # First, set the transaction to read-only mode
        status, result = conn.execute_void(
            "BEGIN TRANSACTION READ ONLY"
        )
        if not status:
            raise DatabaseToolError(
                f"Failed to start read-only transaction: {result}",
                code="TRANSACTION_ERROR"
            )

        try:
            # Execute the actual query
            status, result = conn.execute_2darray(query)

            if not status:
                raise DatabaseToolError(
                    f"Query execution failed: {result}",
                    code="QUERY_ERROR"
                )

            # Format the result
            columns = []
            rows = []

            if result and 'columns' in result:
                columns = [col['name'] for col in result['columns']]

            if result and 'rows' in result:
                rows = result['rows']

            return {
                'columns': columns,
                'rows': rows,
                'row_count': len(rows)
            }

        finally:
            # Always rollback - we're read-only anyway