PERF: MultiIndex equals method got 20x slower · Issue #43549 · pandas-dev/pandas (original) (raw)

• I have checked that this issue has not already been reported.
• I have confirmed this issue exists on the latest version of pandas.
• I have confirmed this issue exists on the master branch of pandas.

Reproducible Example

from dateutil import tz
import pandas as pd
from time import time

dates = pd.date_range('2010-01-01', periods=1000, tz=tz.tzutc())
index = pd.MultiIndex.from_product([range(100), dates])
index2 = index.copy()
start_time = time()
index.equals(index2)
used_time = time() - start_time
print("Took", int(used_time*1000), "milliseconds")

Installed Versions

commit : 73c6825
python : 3.9.6.final.0
python-bits : 64
OS : Darwin
OS-release : 20.5.0
Version : Darwin Kernel Version 20.5.0: Sat May 8 05:10:33 PDT 2021; root:xnu-7195.121.3~9/RELEASE_X86_64
machine : x86_64
processor : i386
byteorder : little
LC_ALL : en_US.UTF-8
LANG : en_US.UTF-8
LOCALE : en_US.UTF-8

pandas : 1.3.3
numpy : 1.21.2
pytz : 2021.1
dateutil : 2.8.2
pip : 21.2.4
setuptools : 57.4.0
Cython : None
pytest : None
hypothesis : None
sphinx : None
blosc : None
feather : None
xlsxwriter : None
lxml.etree : None
html5lib : None
pymysql : None
psycopg2 : None
jinja2 : None
IPython : None
pandas_datareader: None
bs4 : None
bottleneck : None
fsspec : None
fastparquet : None
gcsfs : None
matplotlib : None
numexpr : None
odfpy : None
openpyxl : None
pandas_gbq : None
pyarrow : None
pyxlsb : None
s3fs : None
scipy : None
sqlalchemy : None
tables : None
tabulate : None
xarray : None
xlrd : None
xlwt : None
numba : None

Prior Performance

This issue did not exist in pandas 1.2.5. The timing measured by the script with pandas 1.2.5 on my computer is about 30 milliseconds, while the timing in pandas 1.3.1, 1.3.2 and 1.3.3 is about 600 ms. Thus there has been a 20x increase in run time. This severely impacts the performance of our application. A section of our code that used to take about 30 seconds, now takes about 10 minutes (that code uses pd.concat a lot, which in turn calls MultiIndex.equals).