[pmwiki-users] PmWiki scalebility questions (newbie)

[Tom Lederer]

Thanks. There are a some Lock(x)'s in cookbook and scripts... now we  
are looking into those.

And we are not 100% about the .flock being the problem... we are just  
narrowing the choices down.

Best Regards,
Tom
-- 

Tom
http://www.celok.de


Am 19.10.2006 um 16:25 schrieb Patrick R. Michaud:

> On Thu, Oct 19, 2006 at 03:22:21PM +0200, Tom Lederer wrote:
>> Thanks for the enlightenment. Assuming that indeed a recipe causes
>> the locks: can anybody tell me how to look for the right terms to
>> find the recipes that use the flock?
>>
>> I.e. is it a special php function that i can grep for?
>
> Try looking for either "Lock("  (the PmWiki function) or
> "flock("  (the PHP function).
>
> Also, are you able to confirm that it's the saving of pages
> that is causing the delays in displaying the page?  I.e.,
> that no pages can be read or displayed while a page save
> is taking place?
>
> Pm
>
>>> On Thu, Oct 19, 2006 at 02:16:00PM +0200, Tom Lederer wrote:
>>>> i kinda re-open this thread. Having a relatively large wiki  
>>>> (wiki.d:
>>>> 33 MB in 5000 pages, Version 2.1.11 (Doh!)) running and facing some
>>>> performance issues lately, we think we discovered a problem with  
>>>> the
>>>> flock file. So i would like to know if we are correct and how to
>>>> improve.
>>>>
>>>> From what we learned the situation seems to be like this:
>>>>
>>>> Every page access process sets a read lock (with flock). Now if a
>>>> page should be changed, the writing process needs to wait for  
>>>> all old
>>>> reading processes to end, and does not allow any new reading
>>>> processes to set a lock.
>>>
>>> While PmWiki once worked this way a very long time ago (April 2005,
>>> prior to 2.0.0), it doesn't any longer.  Simply reading or
>>> accessing a page doesn't require a lock -- locks are set only
>>> when writing a page.
>>>
>>> So, if a page should be changed, the writing process only needs to
>>> wait for any other writing processes to end, and none of the
>>> read processes are blocked.
>>>
>>> (Of course, a recipe might be misusing the lock file and setting
>>> a read lock on every page access, but the PmWiki core doesn't
>>> do this.)
>>>
>>>> Is it possible that this results in page request times of several
>>>> seconds (1-30)?
>>>
>>> Not likely.  There must be something else that is causing the delay.
>>>
>>>> Can performance be improved by introducing per-group lock files?
>>>
>>> Per-group lock files don't really help here -- whenever a page
>>> is saved, we're actually writing pages across several groups
>>> (e.g. Site.AllRecentChanges, .pageindex, .notifylist), and this
>>> will only increase once we add some of the commenting and
>>> blogging features.
>>>
>>> Pm
>>>
>>
>>
>