Hi,
I am trying to load files into a dictionary for analysis. the size of the
dictionary will grow quite large (several million entries) and as inserting
into a dictionary is roughly O(n) I figured if I loaded each file into it's
own dictionary it would speed things up. However it did not.
So I decided to write a small test program (attached)
As you can see I am inserting one million entries a time into a map. I ran
the tests where I put all three million entries into one map and one where I
put one million each into it's own map.
What I would have expected is that if I insert one million into it's own map
the time to do that would be roughly constant for each map. Interestingly it
is not. It's about the same as if I load everything into one map.
Oh and I have 4G of RAM and the test consumes about 40% at it's max. I even
run the test on one of our servers with 64G of RAM, so I can rule out
swapping as the issue.
Can anyone explain this oddity? Any insight is highly appreciated.
Here's the output of the test runs:
$ ./dicttest.py -t 0
Inserting into one map
Inserting 100 keys lasted 0:00:26 (38019 1/s)
len(map) 100
Inserting 100 keys lasted 0:01:17 (12831 1/s)
len(map) 200
Inserting 100 keys lasted 0:02:23 (6972 1/s)
len(map) 300
total 300
$ ./dicttest.py -t 1
Inserting into three maps
Inserting 100 keys lasted 0:00:32 (30726 1/s)
len(map) 100
Inserting 100 keys lasted 0:01:29 (11181 1/s)
len(map) 100
Inserting 100 keys lasted 0:02:23 (6957 1/s)
len(map) 100
total 300
Thanks,
Lothar
,[ /home/lothar/tmp/dicttest.py ]
| #!/usr/bin/python
| # -*- coding: utf-8 -*-
|
| import datetime
| import optparse
| import sys
| import time
|
|
|
|
| def fillDict(map, nop, num, guid):
| before = time.time()
|
| for i in xrange(0, num):
| key = (i, guid)
| if not nop:
| map[key] = ([], {})
|
| after = time.time()
| elapsed = (after - before)
| if elapsed <= 0:
| divide = 1.0
| else:
| divide = elapsed
| elapsedTime = datetime.timedelta(seconds=int(elapsed))
| print("Inserting %d keys lasted %s (%d 1/s)" % (num, elapsedTime, (num /
| divide))) print("len(map) %d" % (len(map)))
|
|
| def test0(nop, num):
| print("Inserting into one map")
| map = {}
| fillDict(map, nop, num, "0561c83c-9675-4e6f-bedc-86bcb6acfd71")
| fillDict(map, nop, num, "0561c83c-9675-4e6f-bedc-86bcb6acfd72")
| fillDict(map, nop, num, "0561c83c-9675-4e6f-bedc-86bcb6acfd73")
| print("total %d" % (len(map)))
|
|
| def test1(nop, num):
| print("Inserting into three maps")
| map1 = {}
| map2 = {}
| map3 = {}
| fillDict(map1, nop, num, "0561c83c-9675-4e6f-bedc-86bcb6acfd71")
| fillDict(map2, nop, num, "0561c83c-9675-4e6f-bedc-86bcb6acfd72")
| fillDict(map3, nop, num, "0561c83c-9675-4e6f-bedc-86bcb6acfd73")
| total = 0
| for map in [map1, map2, map3]:
| total += len(map)
| print("total %d" % (total))
|
|
|
| if __name__ == "__main__":
| usage = "USAGE: %prog [options]"
| description="test"
| version="%prog 1.0"
|
| parser = optparse.OptionParser(usage=usage, version=version,
| description=description) parser.add_option(
| "-t",
| "--testnum",
| action="store",
| dest="testnum",
| help="the number of the test to execute",
| type="int",
| default=1
| )
| parser.add_option(
| "-i",
| "--iterations",
| action="store",
| dest="iterations",
| help="the number of iterations",
| type="int",
| default=100
| )
| parser.add_option(
| "-n",
| "--nop",
| action="store_true",
| dest="nop",
| help="don't store in the dictionary only load and parse",
| default=False
| )
|
| (options, args) = parser.parse_args()
|
| testmap = {
| 0:test0,
| 1:test1,
| }
|
| test = testmap[options.testnum]
|
| test(options.nop, options.iterations)
`
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