distributed: Bokeh dashboard failures

I think I’ve seen other reports of this recently, but here’s an example of the bokeh dashboard being sad:

https://gist.github.com/mrocklin/417439bf259b8974b502e67d2ac98f22

from dask.distributed import Client
client = Client()

import zarr
import numpy as np
import dask.array as da


n = (100000, 100000)
chunksize = (5000, 5000)
input = zarr.ones(n, chunks=chunksize)

def f1d(chunk):
    return chunk.sum(keepdims=True)

def f2d(chunk, axis=None):
    return chunk.sum(axis=axis, keepdims=True)

x = da.from_array(input, chunks=chunksize)
a = x.map_blocks(f1d)
b = x.map_blocks(f2d, axis=0)
c = x.map_blocks(f2d, axis=1)

import dask
aa, bb, cc = dask.persist(a, b, c)

BokehUserWarning: ColumnDataSource's columns must be of the same length. Current lengths: ('alpha', 519), ('color', 481), ('duration', 519), ('duration_text', 481), ('key', 481), ('name', 481), ('start', 519), ('worker', 481), ('worker_thread', 481), ('y', 519)
BokehUserWarning: ColumnDataSource's columns must be of the same length. Current lengths: ('alpha', 555), ('color', 483), ('duration', 555), ('duration_text', 483), ('key', 483), ('name', 483), ('start', 555), ('worker', 483), ('worker_thread', 483), ('y', 555)
BokehUserWarning: ColumnDataSource's columns must be of the same length. Current lengths: ('alpha', 582), ('color', 490), ('duration', 582), ('duration_text', 490), ('key', 490), ('name', 490), ('start', 582), ('worker', 490), ('worker_thread', 490), ('y', 582)
BokehUserWarning: ColumnDataSource's columns must be of the same length. Current lengths: ('alpha', 614), ('color', 478), ('duration', 614), ('duration_text', 478), ('key', 478), ('name', 478), ('start', 614), ('worker', 478), ('worker_thread', 478), ('y', 614)
BokehUserWarning: ColumnDataSource's columns must be of the same length. Current lengths: ('alpha', 644), ('color', 492), ('duration', 644), ('duration_text', 492), ('key', 492), ('name', 492), ('start', 644), ('worker', 492), ('worker_thread', 492), ('y', 644)
BokehUserWarning: ColumnDataSource's columns must be of the same length. Current lengths: ('alpha', 672), ('color', 480), ('duration', 672), ('duration_text', 480), ('key', 480), ('name', 480), ('start', 672), ('worker', 480), ('worker_thread', 480), ('y', 672)
BokehUserWarning: ColumnDataSource's columns must be of the same length. Current lengths: ('alpha', 700), ('color', 492), ('duration', 700), ('duration_text', 492), ('key', 492), ('name', 492), ('start', 700), ('worker', 492), ('worker_thread', 492), ('y', 700)

Sorry for the not entirely minimal example. Hopefully it’s easy to reproduce though.