[wp-hackers] Running a network

Mon Dec 31 12:24:32 UTC 2012

Six months is a long time to have a problem!

You need to install something to profile your WordPress install and see exactly what is going on under the hood and what is causing this performance issue.

Here are some links to tools you could use. Time stack might be easiest if you have access to a Memcached server, otherwise maybe the debug bar extender (which I've never used); failing that you could install one of the others but then you're getting further into sysadmin!
https://github.com/joehoyle/Time-Stack
http://pecl.php.net/package/xhprof
http://wordpress.org/extend/plugins/debug-bar-extender
http://xdebug.org/

Simon

WP Sites Limited 
www.wpsites.co.uk

On 31 Dec 2012, at 12:00, wp-hackers-request at lists.automattic.com wrote:

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> Today's Topics:
> 
>   1. Running a network (Shasta Willson)
>   2. Re: Running a network (Carl Roett)
>   3. Re: Running a network (Shasta Willson)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Sun, 30 Dec 2012 12:11:12 -0800
> From: Shasta Willson <shastaw at gmail.com>
> Subject: [wp-hackers] Running a network
> To: wp-hackers at lists.automattic.com
> Message-ID:
> 	<CAGguigczDd8yjBX_rt0j0TJxCybZF18-tqHTxke0reHLcKV+qA at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
> 
> I've been having an issue with site speed for some time.  My site is a
> commerce site with subdomain sites for author's book creation.
> (Litsam.com)  At first I blamed wp e-commerce, which surely loads a
> lot of files, but moving to another shopping cart didn't help.  I also
> realized that it was often the very first http call that would take a
> long time -- up to 19 seconds once, but not infrequently in the 5-15
> seconds range. That suggested that reducing the number of files being
> loaded or other standard optimizations wouldn't help.
> 
> So then I decided it was the host I'd moved to and I started a move to
> another new host. Things on the main commerce site were spiffy-fast at
> the new host right up until I realized my network wasn't actually
> active because I hadn't turned on wildcard domains.  As soon as I did
> that the site started to exhibit the same behaviour. Sometimes it was
> fine, but periodically it was definitely not fine.
> 
> So that's two hosts that were doing ok until I turned on networking.
> 
> I've been trying to work up the gumption to research server/wildcard
> configurations. If I wanted to be a sysadm, I would have been one.
> *sigh*
> 
> But today I found another apparently network-related issue that leaves
> me wondering how to configure a Wordpress subdomain network install so
> that it isn't a resource hog. It must be possible, as I know people
> are using this feature commercially...
> 
> About a year ago I set up a prototype site for a client who wanted to
> use some fancy image transitions, so I installed skitter
> (http://thiagosf.net/projects/jquery/skitter/). Initial experiments
> went fine but the project lapsed for half a year, and when she was
> ready to pick it up I'd gotten "organized" and started using a
> subdomain network to host my prototypes, rather than freestanding
> installs for each one.  I moved her over to the new system for
> consistency.
> 
> Immediately I had problems with skitter. Some effects never worked,
> though they worked on the skitter site.  Others were jumpy and
> unreliable.  I wasted a half a dozen hours trying different versions
> of jquery, making sure I was using exactly the same versions of all
> the files as the skitter site, etc. Nothing helped.
> 
> Until I moved the site to a freestanding Wordpress install (off the
> network) to go live.  Suddenly skitter is working perfectly again.
> 
> This suggests to me that simply having a network is somehow impacting
> performance enough to cause the fairly intensive animation system to
> fail. It's not a script conflict -- I spent hours ensuring that --
> it's actually the exact same code running fine in a lone Wordpress
> site and failing in a networked subdomain site.
> 
> Anyone else had this kind of problem, or have any suggestions?
> Currently the only plans I've come up with for my main commerce site
> are either to throw more server resources at the problem and see it if
> goes away, or to redesign it so that I'm not using a subdomain
> network.
> 
> I'd rather fix it, if a fix exists.
> 
> - Shasta
> 
> 
> ------------------------------
> 
> Message: 2
> Date: Sun, 30 Dec 2012 15:10:11 -0700
> From: Carl Roett <carlroett at gmail.com>
> Subject: Re: [wp-hackers] Running a network
> To: wp-hackers at lists.automattic.com
> Message-ID:
> 	<CAM0n84CpWrTvLbm4L-RCaoSEoRBUwD7_78UvsrvV+FjzLJZS_Q at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
> 
> Given sufficient resources, WordPress multisite is usually well-behaved on
> large networks.
> 
> Typical causes of multisite performance problems:
> 
> 1) Hundreds of thousands of spam profiles on a site that are flagged as
> spammers. Each of those spam profiles consumes ~10 DB tables. We had one
> site with 100K+ auto-flagged spam profiles on it that had over *a million*
> db tables. Deleting those tables dramatically improved site load times.
> 
> 2) Excessive crawler hits, causing memory starvation on the server, aborted
> PHP threads,   SQL server throttling, and bandwidth throttling. In one case
> we had Google hitting a large site dozens of times a second, causing the
> active PHP threads to consume the entire 1GB cap on the server. The site
> owner accidentally triggered the crawler flood by changing the templates on
> their site, which changed the page structure on their site, and caused
> Google to re-crawl 50,000+ pages. To somebody that can't view the server
> stats, the site would load incredibly slowly and possibly throw error pages
> from time to time.
> 
> 3) Javascript code that operates on multisite profiles but not the root
> blog, and which blocks the DOM ready event until complete. Many possible
> sources including plugins and themes.
> 
> 4) However, if:
> 
> a) You had multisite up and running and could view the individual user blogs
> b) Then you enabled wildcard domains
> c) Then the site became very slow
> 
> That means there's something wrong with your DNS settings. Something is
> timing out, then hitting the next node up and finding what its looking for.
> 
> ^C^
> 
> 
> ------------------------------
> 
> Message: 3
> Date: Sun, 30 Dec 2012 14:20:45 -0800
> From: Shasta Willson <shastaw at gmail.com>
> Subject: Re: [wp-hackers] Running a network
> To: wp-hackers at lists.automattic.com
> Message-ID:
> 	<CAGguiget0+=4EBLZanScPnvmRkenaLQ_42dw_BRNp6U-CxHSsg at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
> 
> On Sun, Dec 30, 2012 at 2:10 PM, Carl Roett <carlroett at gmail.com> wrote:
>> 
> Probably not spam profiles or lots of hits as it's a relatively small
> site (~100 pages tops) with only the accounts I manually create.
> 
>> 3) Javascript code that operates on multisite profiles but not the root
>> blog, and which blocks the DOM ready event until complete. Many possible
>> sources including plugins and themes.
> 
> OOOH...tell me why it would matter if I had javascript code that
> operated on multisite but not on the root blog?  My subdomain "author"
> sites rely on quite a bit of display-altering javascript that has
> nothing to do with the parent site.
> 
>> 4) However, if:
>> 
>> a) You had multisite up and running and could view the individual user blogs
>> b) Then you enabled wildcard domains
>> c) Then the site became very slow
> 
> No, I didn't have multisite running.  I *thought* I did, went through
> testing the main site's functionality (shopping cart etc. etc.) was
> pretty happy with the new server, went to the first subdomain and it
> wasn't there.  Turned on the wildcard domains setting.  As soon as I
> did, it went back to dog-slow.
> 
> And THANK YOU.  That is absolutely the most robust answer I've gotten
> in six months of asking around at various places.
> 
> - Shasta
> 
> 
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