Hello

I'm not a professional, but I'm not a beginner either
I have been working with matplotlib since 2013 (see for example issue # 1957)

my system:

Win10(64), IDE PyCharm, python 3.8.2 (64), numpy 1.19.2, matplotlib 3.2.2 and 3.3.0

I mainly use:

matplotlib.pyplot as plt
fig, ax=plt.subplot(...)
ax.plot(...)
ax.fill_between(...)
plt.show()

my plot data:

4 rows each 525600 points (365day * 24hour * 60 min)

the problem:

with mpl 3.2.2 the creation of the plot example 1 takes 4 seconds
but
with mpl 3.3.0 the creation of the plot example 1 takes 31 seconds

and

with mpl 3.2.2 the creation of the plot example 2 takes 13 seconds
but
with mpl 3.3.0 the creation of the plot example 2 takes 82 seconds

example 1

example 2

the question:

Why is this enormous extension of the creation time?
What has changed from mpl 3.2.2 to 3.3.0?

Thank you