Rails *that* slow?

I’m working on my first little rails-application. It’s a rewrite of a
gallery-script i once made (in PHP): http://notdotnet.net

However - my rails-version is waaay to slow :frowning:
http://r.notdotnet.net/

I don’t do any heavy image-processing, I don’t have any
killer-algorithms with a time complexity on O(n^n), and I don’t use any
major hacks.
The only “stupid” thing i really do is an “ORDER BY RAND()” on a table
with 8000 rows, which is quite heavy, but it shouldn’t take that long,
and i do the same in PHP which works fine.

I then signed up for a new (free) webhost and installed my application
there to see if my host was the problem. It performs a bit better on the
free one, but is still really slow :confused:
http://94383.hostmyapplications.com/

Since it don’t mind sharing the source code (nothing brilliant - just a
noobs first project =) you can get it here (no db-config file)):
http://94383.hostmyapplications.com/rails_slow.tar.gz (and if you like -
the database: http://94383.hostmyapplications.com/mysql.zip).

Do you have any idea why i get such bad performance?

thanks in advance.

On 8/6/06, Anders [email protected] wrote:

with 8000 rows, which is quite heavy, but it shouldn’t take that long,
the database: http://94383.hostmyapplications.com/mysql.zip).

Do you have any idea why i get such bad performance?

Are you in production mode?

Joe

On Sun, 2006-08-06 at 23:53 +0200, Anders wrote:

The only “stupid” thing i really do is an “ORDER BY RAND()” on a table
with 8000 rows, which is quite heavy, but it shouldn’t take that long,
and i do the same in PHP which works fine.

Is your database schema the same as in PHP version? I believe ORDER BY
RAND() looks at all your data in each row; the bigger the amount of data
the more to look at. So if you added more columns, like descriptions,
etc., it would be slower. I guess paging with LIMIT is not an option as
you may get repeats, right?

Ed

Do you have any idea why i get such bad performance?

Typical performance killers:

  • running under webrick or via plain CGI instead of fastcgi, and/or
    with lighttpd, with mongrel, etc.

  • running in development mode instead of production mode

Rick

http://www.rickbradley.com MUPRN: 418
| to some problem. In
random email haiku | fact, many people think it does:
| Part of the problem.

Gmail User wrote:

On Sun, 2006-08-06 at 23:53 +0200, Anders wrote:

The only “stupid” thing i really do is an “ORDER BY RAND()” on a table
with 8000 rows, which is quite heavy, but it shouldn’t take that long,
and i do the same in PHP which works fine.

Is your database schema the same as in PHP version? I believe ORDER BY
RAND() looks at all your data in each row; the bigger the amount of data
the more to look at. So if you added more columns, like descriptions,
etc., it would be slower. I guess paging with LIMIT is not an option as
you may get repeats, right?

Ed

Almost - but not quite the same schema. However - the rails-version is
smaller since i made a proper database design here. Also - I only do
ORDER BY RAND() on the front page. When you go into a category it dosn’t
sort by random anymore (but by the numbers of views).

And no - I’m not in production mode. Do that really help that much? I
tried tweeking “development.rb” with caching and such - but that didn’t
really help.

  • running under webrick or via plain CGI instead of fastcgi, and/or
    with lighttpd, with mongrel, etc.

It’s not runing under webrick, and since i forund mod_fastcgi under
loaded modules in a phpinfo()-file I assume (can I do that) that fastcgi
also is available for rails

  • running in development mode instead of production mode

Okey - that might be the problem. How do I ten go into production mode?
I don’t have SSH-access, and uncommenting “ENV[‘RAILS_ENV’] ||=
‘production’” just kills my application with an error500 :frowning:

Hi Anders,

may be you should tell something about the content you are linking to.
Someone might be offended!

Cheers,
Jan

Jan P. wrote:

Hi Anders,

may be you should tell something about the content you are linking to.
Someone might be offended!

Cheers,
Jan

argghh - I’m really sorry. Actually the script should only show worksafe
images on the front page (like notdotnet.net), but since i havn’t
“marked” the images yet, that feature dosn’t work.

I didn’t think about that!

if it’s not to late :stuck_out_tongue: there may be some not-worksafe images on
r.notdotnet.net and http://94383.hostmyapplications.com/

On 8/6/06, Anders [email protected] wrote:

It’s not runing under webrick, and since i forund mod_fastcgi under
loaded modules in a phpinfo()-file I assume (can I do that) that fastcgi
also is available for rails

You need to make sure that public/.htaccess makes connection to
dispatch.fcgi instead of dispatch.cgi.

  • running in development mode instead of production mode

Okey - that might be the problem. How do I ten go into production mode?
I don’t have SSH-access, and uncommenting “ENV[‘RAILS_ENV’] ||=
‘production’” just kills my application with an error500 :frowning:

That sounds like a rights issue. Make sure that /log/* and /tmp* are
writeable. You can test this by simply making all these chmod 777

On Aug 6, 2006, at 3:34 PM, Anders wrote:

  • running under webrick or via plain CGI instead of fastcgi, and/or
    with lighttpd, with mongrel, etc.

It’s not runing under webrick, and since i forund mod_fastcgi under
loaded modules in a phpinfo()-file I assume (can I do that) that
fastcgi
also is available for rails

No that definitely does not mean that your rails app will just work
with fcgi. It means more then likely you are running in cgi mode
which is really slow because it has to load the entire framework into
memory from disk on each requests. Also there is a huge difference
between development and production mode.

So you need to switch to production mode and verify your server
config to make sure you are using fcgi instead of cgi.

-Ezra

You need to make sure that public/.htaccess makes connection to
dispatch.fcgi instead of dispatch.cgi.

hmm - when i do that my application just stops responding :confused: no error,
no log, nothing.

as said before - this page (same server) say’s that mod_fastcgi is
installed: http://phpinfo.levelup.dk/folder/index.php

any ideas?

Instead of saying “slow,” it would be helpful if you benchmarked the
site, running in production mode on a server, not desktop machine. Most
people use ab or httperf to find out how many requests/sec their site
can serve.

An average rails site in production mode with no caching enabled may
serve as few as 20 r/s or as many as 120 r/s. If you begin to enable any
of the caching features, your pages served increase dramatically.

If you just did this rewrite, isn’t it a bit early to be worrying about
performance? It sounds like you should research your deployment options.
Many have been using lighttpd/fastcgi to serve dynamic content, but more
and more, people are using Mongrel clusters.

Note: Just because your phpinfo() says that mod_fcgi is installed does
not mean you’ve set up rails to work with it.

No that definitely does not mean that your rails app will just work
with fcgi.

Right

It means more then likely you are running in cgi mode
which is really slow because it has to load the entire framework into
memory from disk on each requests. Also there is a huge difference
between development and production mode.

Yes - I learned that now. Right now I’m running in production mode, and
the speed is much better.

However - I’m almostsure that I’m not running in fcgi mode. What I’m
trying to figure out now is:

  1. Can i setmy application up in fcgi mode (without talking to the
    support and get them to change something on the server).

  2. If I can - how do i do it?

As I said i changed “RewriteRule ^(.)$ dispatch.cgi [QSA,L]" to
"RewriteRule ^(.
)$ dispatch.fcgi [QSA,L]” in my .htaccess-file. But
that just resulted in that the server didn’t response, no errors - no
logs.

thanks in advance

Anders wrote:

between development and production mode.

  1. If I can - how do i do it?

As I said i changed “RewriteRule ^(.)$ dispatch.cgi [QSA,L]" to
"RewriteRule ^(.
)$ dispatch.fcgi [QSA,L]” in my .htaccess-file. But
that just resulted in that the server didn’t response, no errors - no
logs.

thanks in advance

It sounds like you need the appropriate apache config bits.

Check out http://wiki.rubyonrails.com/rails/pages/FastCGI and
http://wiki.rubyonrails.com/rails/pages/Debian+mod_fastcgi+Notes

Here is my .htaccess snippet:

AddHandler fcgid-script .fcgi
AddHandler cgi-script .cgi
Options +FollowSymLinks +ExecCGI

RewriteEngine On

RewriteRule ^$ index.html [QSA]
RewriteRule ^([^.]+)$ $1.html [QSA]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$ dispatch.fcgi [QSA,L]

ErrorDocument 500 /500.html


Here, is my httpd.conf snippet., it might work in .htaccess (replace the
path with myrailsapp to reflect your setup):

configuration file for fast_cgi

needed for ruby on rails

LoadModule fcgid_module modules/mod_fcgid.so

DefaultInitEnv RAILS_ENV production AddHandler fcgid-script .fcgi SocketPath /var/log/httpd/fcgidsock/ IdleTimeout 3600 ProcessLifeTime 7200 MaxProcessCount 8 DefaultMaxClassProcessCount 2 IPCConnectTimeout 8 IPCCommTimeout 60 DefaultInitEnv RAILS_ENV production

<Directory /var/www/myrailsapp/current/public/>
Options ExecCGI +FollowSymLinks
AllowOverride All
order allow,deny
allow from all


steve ross wrote:

If you just did this rewrite, isn’t it a bit early to be worrying about
performance? It sounds like you should research your deployment options.
Many have been using lighttpd/fastcgi to serve dynamic content, but more
and more, people are using Mongrel clusters.

Running Mongrel with Apache?

I’m frighteningly new to Rails (with about 6 months of Ruby) and have
some really simple questions about Rails based on some past experiences
I’ve had with other (perl) frameworks.

First, how do you manage static pages? In another world I would just
use Template under perl and build static HTML. Under perls HTML::Mason
I would set the cache and have no refresh (or weekly).
Is this essentially the approach you have under Rails – cache for days?

You can use mod_proxy to forward given ports to your mongrels. You can
use
mongrel_cluster to start multiple mongrels at a time. Mongrel can serve
static content, although I’m not sure what the efficiency of that is.
Maybe
Zed can weigh in on a good configuration.

Tom A. wrote:

Is this essentially the approach you have under Rails – cache for days?


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On 8/8/06, Tom A. [email protected] wrote:

[email protected]
http://lists.rubyonrails.org/mailman/listinfo/rails

You can cache pages if you like. You can’t controller actions on that
page
tho.

IMHO the caching options are quite flexible. At least, they’re flexible
enough for me at the moment.

http://api.rubyonrails.org/classes/ActionController/Caching.html

Basically if rails finds a request with a document that exists under the
public folder (or subfolder) it will serve it (or maybe the webserver
does?). Otherwise it will look in routes and act accordingly. At least
this
is my understanding of it.

Look at:

http://blog.lighttpd.net/articles/2006/07/18/mod_proxy_core-commited-to-svn

lighttpd does proxying as well.

View this message in context:
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I wasn’t planning on starting a cluster of application servers.
I was just wondering what might be effective for splitting static and
dynamic pages apart.

But you mentioned mod_proxy as one way of getting speed which would be
quite effective. I supposed lighttpd does not do this?

I haven’t tried it, but I think in 1.5.0 it does…

http://blog.lighttpd.net/articles/2006/07/15/the-new-mod_proxy_core

I wasn’t planning on starting a cluster of application servers.
I was just wondering what might be effective for splitting static and
dynamic pages apart.

But you mentioned mod_proxy as one way of getting speed which would be
quite effective. I supposed lighttpd does not do this?

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