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Performance Issues with large data sets since 2.x.x #5790
Description
Hey, we found some performance issues regarding large data sets.
Here is an example with 100k datapoints. When we use the plotly-2.2.0.min.js, the whole plot freezes and has a very bad performance. When we use the plotly-1.58.4.min.js, everything works fine.
Reacted by Simon and Matt Klengson
Reacted by Eros Valzasina, Simon, Jude Shamsi, Frederick Meyers and Matt Klengson
Activity
[-]Performance Issues with large data sets[/-][+]Performance Issues with large data sets since 2.x.x[/+]archmoj commentedon Jun 30, 2021
Please note that the default
hovermodein v1 isxand in v2 isclosest.So with v2 you could simply set
layout.hovermodeto 'x' for this graph.nicolaskruchten commentedon Jun 30, 2021
Let's investigate this one a bit more... 100k points shouldn't slow down this much in any hovermode, right?
nicolaskruchten commentedon Jun 30, 2021
The plots here are much faster and have hovermode=closest (and are rendered with 2.2.0) https://plotly.com/python/webgl-vs-svg/ ... what's the difference? Is closest hovermode much more efficient with a gaussian distribution of points in x/y or something?
sean-mcl commentedon Jul 1, 2021
Just tested it with sin data here. The performance impact is huge! When I use linear data, its almost unusable.
ordinaryorange commentedon Mar 15, 2022
I can confirm it is definitely a hovermode problem.
I was generating a WebGL scatter of circa 300,000 points where there was small Y variability over X, and the perf was awful
If I generate a synthetic scatter with a larger distribution over Y the perf improves. Changing it to a full continuous Y distribution the perf is just fine.
Coming back to my original scatter, if I set HoverMode=false, no perf issues
HoverMode.x or HoverMode=xUnified = not too bad
Hovermode.y, HoverMode.yUnified or Hovermode.Closest = awful perf
So as @nicolaskruchten indicates it is related to the distribution of data for a given axis.
Anything over about 50,000 points starts to lag if there is no distribution of data
Running v2.6.3 here
JudeShamsi commentedon Aug 21, 2022
Has anyone found any solutions to handling the issue? Setting the hovermode to 'x' has improved the hover performance slightly, however as soon as I hover over an area on the screen with many zeros, my app crashes. I'm using react-plotly 2.5.1. This only occurs once I plot more than 100k points. I'm already using scattergl as well.
hobob0t commentedon Mar 20, 2023
+1 I went back to matplotlib because I need to be able to look at large data sets. Currently attempting a dataframe with 105,983 rows, and anything over 4 columns is just awful.
As others have stated, forcing webgl doesn't help (I think it's default for plotly express anyway). Turning hovermode off works pretty well but drawing the canvas is still a chore. Plus, hovermode is half the reason I use plotly.
If this is truly unfixable due to JS limitations, then I think plotly should feature an automatic subsampling option to reduce the number of points shown.
iDevGeek commentedon Jun 5, 2025
Still issue in Plotly 3.x.x... I would be very happy if I could downsample based on the zoom level (using React - Plotly) but that feature is lacking.
saravpatel commentedon Jun 10, 2025
I also face the same issue, rendering 100k+ points in Plotly 3.x.x. I even tried mode: "lines+markers", type: "scattergl", hovermode: "x" || "y" || "x unified", but it's laggy and nothing works for me.
sarintom commentedon Nov 20, 2025
Same here. Currently latest version that doesn't have this issue is 1.58.5 and starting from 2.x.x it freezes the browser.
siiruli commentedon Nov 20, 2025
My comment in #5927 (comment) explains the probable cause of the problem. Setting
spikedistance: 0should help until the problem is fixed.