Plotly Pointcloud does not work with date column

Dash Python
1

I am experiencing slow rendering and load times with Scattergl for my dataset (which is quite large). So I figured I would try to use Pointcloud. But when I try to use my dataframe’s Date column as the x-axis it does not work.

My DataFrame is constructed like this:

timestamp Date ID data
1541516362 2018-11-06 15:59:22+01:00 51 0
1541527532 2018-11-06 19:05:32+01:00 76 -41
⋮ ⋮ ⋮ ⋮
1557496108 2019-05-10 15:48:28+02:00 71 -15

where timestamp is a UTC UNIX timestamp, and the Date column is added by me after creating the DataFrame by reading from a database, like so:

import dash
import dash_core_components as dcc
import dash_html_components as html
from dash.dependencies import Input, Output
import pandas as pd
import plotly.graph_objs as go

[...]  # Code that reads database into dataframe etc.

tz = "Europe/Oslo"
df["Date"] = pd.to_datetime(df["timestamp"], unit="s", utc=True
df.Date = df.Date.dt.tz_convert(tz)

I have a html-div in the app layout on the form:

html.Div(
    id="mhp-graph-div",
    children=dcc.Graph(
        style={"bgcolor": "rgba(0,0,0,0)"},
        id="mhp-graph",
        config={"scrollZoom": True}
    ),
)

which I update using another html-div with a dcc.Dropdown like so:

@app.callback(Output("mhp-graph", "figure"),
              [Input("live-dropdown", "value")])
def update_live_graph(value):
    fig = {
        "data": [
            go.Pointcloud(
                x=df[df["ID"] == value]["Date"],
                y=df[df["ID"] == value]["data"],
                marker={"sizemin": 0.5, "sizemax": 100},
            )
        ]
    }
    return fig

However, when I run this code, nothing gets plotted, and the date axis is going from early 2000 to early 2001 with no data points plotted. But if I try to plot using the timestamp column as x-axis, there’s no problems, it works like a charm. The dataframe is sorted by rising timestamp/date, and the first and last in the table I included above is the first and last in the dataset (late 2018 to april this may this year).

Anyone that can help with this issue?

EDIT: I also just noticed that loading the graph with Scattergl with the Date column takes approximately 7 times longer than loading it with the timestamp column. Is there really such a performance-difference with dates vs uint32? And is there a way to get around this?

Image of the plot when using Date column

image
image.png1225×584 4.75 KB

Image of the plot when using timestamp column

image
image.png1198×581 41.9 KB