In attached file calls of merge_cells at worksheet/worksheet.py from parse_merge() for cycle from reader/worksheet.py causing slow down, especially at the end of parse_merge cycle. In this case it has 13515 merged.mergeCell, near the last iterations one cycle lasts about ~0.5 seconds. File had data range in 63 cols, 463 rows, I deleted it, cause it does not matter for this case.
Uploading also worksheet.py with prints just to see it.
windows 10/64 bit/ python 3.6.4/lxml 184.108.40.206/openpyxl 2.5.3
ubuntu 16.04/64 bit/ python 3.6.3/last lxml/last openpyxl
Using this code to open xlsx:
# -*- coding: utf-8 -*- from openpyxl import load_workbook file_name = r'd:\thiska.xlsx' wb = load_workbook(file_name) # <- this taking too long time ws = wb.active