[Moin-user] performance quirk in 1.2.4

Jim Carroll jcarroll at totality.com
Thu Dec 23 09:33:01 EST 2004


I set up MoinMoin 1.2.4 less than 2 months ago, endeavouring to demonstrate
a proof-of-concept to my co-workers.  So far, I've been the only one adding
content, which hasn't been much.  The proof-of-concept has been blessed, but
I've run into a few snags which I'd like to resolve before relocating
MoinMoin from the slow sandbox to a quicker (supported) platform.  For this
e-mail I'll focus on just the one issue to keep thread clutter to a minimum.
:-)

I noticed that overall the performance of MoinMoin is pretty reasonable,
given the hardware platform I'm got it on.  However, there's a noticeable
delay after clicking Save Changes (after doing Edit/Preview).  I've tried
this a number of times (on various days) and this delay is consistent.
Typically it seems to be at least 5 seconds, but there have been occasions
where it's gone on for much longer.

After rooting around the moinmoin website docco, I added these to
moin_config.py:

show_timings = 1
show_version = 1

Both caused a couple interesting details to surface.  First, the results of
a Preview:

    * send_page = 0.323s
    * total = 0.847s
    * run = 0.534s

And now for a Save Changes:

    * send_page = 0.407s
    * total = 8.350s
    * run = 7.781s

(Quick sidebar:  The show_version displayed this:  "MoinMoin 1.187,
Copyright © 2000-2004 by Jürgen Hermann".  Odd that it doesn't show version
1.2.4, or?)

So I tried to determine why the delay.  Surely it didn't take that long to
post a simple file edit...?

With another window open, I was able to strace the python process
immediately after I hit Save Changes.  What struck me was that the following
line repeats for the majority of the trace:

futex(0x804a160, FUTEX_WAKE, 1, {4, 1074731520}) = 0

And a little earlier in the trace, this:

connect(4, {sa_family=AF_INET, sin_port=htons(8000),
sin_addr=inet_addr("83.137.100.43")}, 16) = 0

I'm not sure they're related, but I suspect they are.  Since this wiki is on
a private intranet, my first question is, how do I stop Moin from trying to
connect to 83.137.100.43?  Presumably it's trying to update the
interwiki...?  Doing so would be of no benefit to anyone else, since noone
external to our company can reach our VLAN.  :)

Second question, is the delay related to the connection to 83.137.100.43?

I did try to research this on the moinmoin site, but ended up finding
finding references to farmconfig.py, which doesn't seem to exist in 1.2.4.
I'll save the description of my attempt to upgrade to 1.3.1 for another
thread.  Also, I'll save the description of some curious behaviour after
enabling the wiki to use mod_python for yet another thread.  :)

Let me know your thoughts/suggestions on optimizing the performance
post-Save Changes.

jc




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