Speeding up plotting large timeseries (x5)

📊 Plotly Python
1

Hello,

I am plotting large timeseries (20 traces of 8760 data points each) with px.area and it takes around 3s to generate the figure (with px.area).
I found a way to speed up significantly (x5/x6) the generation of the figure by using the following ptimisation:

  1. generate the figure with only the first row of data so that we end up with a figure with the traces, legend, etc properly defined
  2. loop through the traces and change x,y with the index, col of the original dataframe

It gives the following decorator you can use to decorate any function generating a figure based on a dataframe as first argument

def two_step_plotting(f):
    # get name of first argument of function f (expected a dataframe)
    df_arg_name = next(iter(inspect.signature(f).parameters))

    @wraps(f)
    def wrapper(*args, **kwargs):
        # get the dataframe argument
        if args:
            df, *args = args
        else:
            df = kwargs.pop(df_arg_name)

        # generate the figure with the first row of df
        kwargs[df_arg_name] = df.iloc[:1]
        fig = f(*args, **kwargs)

        # inject in data traces the full dataframe
        traces = {trace["name"]: trace for trace in fig["data"]}
        x = df.index

        for col, y in df.items():
            trace = traces[str(col)]
            trace["x"] = x 
            trace["y"] = y

        return fig

    return wrapper

# to speedup the function my_figure_generator_function, just use the decorator
@two_step_plotting
def my_figure_generator_function(df, ...):
    ...
    return fig

If you do have the same performance issue as me, would this work for you ?
For the plotly team, could plotly natively be as performant (to avoid needing such decorator ? or is there some intrisic complexities that make this not possible ?