A simple openpyxl profiler to optimized reader

1.patch

--- a/openpyxl/reader/iter_worksheet.py Thu Jan 02 23:46:28 2014 +0100
+++ b/openpyxl/reader/iter_worksheet.py Tue Jan 07 22:26:45 2014 +0100
@@ -254,6 +254,7 @@
                         data_type = Cell.TYPE_FORMULA
                         value = "=" + formula
                     yield RawCell(row, column_str, coord, value, data_type, style_id, None)
+                element.clear()

bench.py

import openpyxl
from memory_profiler import memory_usage

print openpyxl.__version__

f = "openpyxl/benchmarks/files/large.xlsx"

r = openpyxl.load_workbook(f, use_iterators=True)
w = r.worksheets[1]

for n, line in enumerate(w.iter_rows()):
    if n % 50 == 0:
        print n, memory_usage(-1, interval=1)

out.txt

F:\projects\openpyxl>python setup.py develop
running develop
running egg_info
writing openpyxl.egg-info\PKG-INFO
writing top-level names to openpyxl.egg-info\top_level.txt
writing dependency_links to openpyxl.egg-info\dependency_links.txt
reading manifest file 'openpyxl.egg-info\SOURCES.txt'
reading manifest template 'MANIFEST.in'
no previously-included directories found matching 'openpyxl\sample'
writing manifest file 'openpyxl.egg-info\SOURCES.txt'
running build_ext
Creating c:\python27\lib\site-packages\openpyxl.egg-link (link to .)
Adding openpyxl 1.8.0 to easy-install.pth file

Installed f:\projects\openpyxl
Processing dependencies for openpyxl==1.8.0
Finished processing dependencies for openpyxl==1.8.0

F:\projects\openpyxl>python bench.py
1.8.0
0 [28.640625]
50 [198.54296875]
100 [366.6328125]
150 [531.54296875]
200 [700.52734375]
250 [868.36328125]
300 [1032.25]
350 [1195.89453125]
400 [1359.53515625]
450 [1524.5390625]
500 [1689.78515625]
550 [1855.75390625]
600 [2023.0625]
650 [2188.19921875]
700 [2354.12890625]
750 [2521.015625]
800 [2687.07421875]
850 [2852.94140625]
900 [3020.12890625]
950 [3184.36328125]

F:\projects\openpyxl>hg patch 1.patch --no-commit
applying 1.patch

F:\projects\openpyxl>hg patch 1.patch
abort: outstanding uncommitted changes

F:\projects\openpyxl>python bench.py
1.8.0
0 [26.56640625]
50 [54.6953125]
100 [80.68359375]
150 [106.234375]
200 [131.25390625]
250 [156.3203125]
300 [181.2578125]
350 [206.47265625]
400 [231.68359375]
450 [256.8828125]
500 [282.515625]
550 [308.0390625]
600 [333.33984375]
650 [358.58203125]
700 [383.47265625]
750 [408.328125]
800 [433.875]
850 [459.72265625]
900 [484.60546875]
950 [509.8359375]

F:\projects\openpyxl>hg update --clean
1 files updated, 0 files merged, 0 files removed, 0 files unresolved

F:\projects\openpyxl>hg checkout 1.6.2
0 files updated, 0 files merged, 0 files removed, 0 files unresolved

F:\projects\openpyxl>python bench.py
1.6.2
0 [20.4921875]
50 [23.3671875]
100 [23.3671875]
150 [23.3671875]
200 [23.3671875]
250 [23.3671875]
300 [23.58203125]
350 [23.58203125]
400 [23.58203125]
450 [23.58203125]
500 [23.58203125]
550 [23.58203125]
600 [23.59375]
650 [23.59375]
700 [23.59375]
750 [23.59375]
800 [23.59375]
850 [23.59375]
900 [23.57421875]
950 [23.57421875]