import pandas as pd
from itertools import product
import random
countries = ['Australia','Mexico','Finland']
goods = ['Dairy','Wheat','Beef']
data = []
for country, goods in product(countries,goods):
    data.append(dict(
        Country = country,
        Goods = goods,
        Value = random.randint(1000,50000),
        Count = random.randint(100,10000)
    ))

df = pd.DataFrame(data)
df["CountryValueTotal"] = df.groupby('Country')["Value"].transform('sum')
df["%CountryValueTotal"] = df["Value"] / df["CountryValueTotal"] * 100
df["CountryCountTotal"] = df.groupby('Country')["Count"].transform('sum')
df["%CountryCountTotal"] = df["Count"] / df["CountryCountTotal"] * 100

import hvplot.pandas
from holoviews import opts
from holoviews.plotting.links import DataLink

# the following one works - i.e. linked taps
g1 = df.hvplot.bar(x='Country', by='Goods', y='%CountryCountTotal', stacked=False)
g2 = df.hvplot.bar(x='Country', by='Goods', y='%CountryValueTotal', stacked=False)
dlink = DataLink(g1, g2)
g3 = g1 + g2
g3.opts(
    opts.Bars(width=300, height=250, framewise=True, xrotation = 90, tools=['tap']))

# the following one gives an error : ValueError: DataLink can only be applied if overlapping dimension values are equal, bottom column on source does not match target
g1 = df.hvplot.bar(x='Country', by='Goods', y='%CountryCountTotal', stacked=True) # <- stacked = true now
g2 = df.hvplot.bar(x='Country', by='Goods', y='%CountryValueTotal', stacked=True) # <- stacked = true now
dlink = DataLink(g1, g2)
g3 = g1 + g2
g3.opts(
    opts.Bars(width=300, height=250, framewise=True, xrotation = 90, tools=['tap']))