Re: RewriteMaps inefficient (was: [Zope-dev] Apache Mod_rewrite question)

2004-07-16 Thread Dieter Maurer 
Ganesha Shanmuganathan wrote at 2004-7-15 15:57 -0500:
 ... RewriteMap files with the same name are identified ...
That is strange! It looks like a bug in mod_rewrite then. I checked the
source and found that it does compare by map name. Thanks for your
feedback

But the cache is not taken from a global variable but resolved
via a local resource.

I am not sure what this local resource is (I am no Apache expert).
But, I expect that it is virtual host specific.

-- 
Dieter
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Re: RewriteMaps inefficient (was: [Zope-dev] Apache Mod_rewrite question)

2004-07-16 Thread Ganesha Shanmuganathan 
Hi Dieter,

On Fri, 2004-07-16 at 13:10, Dieter Maurer wrote:
 Ganesha Shanmuganathan wrote at 2004-7-15 15:57 -0500:
  ... RewriteMap files with the same name are identified ...
 That is strange! It looks like a bug in mod_rewrite then. I checked the
 source and found that it does compare by map name. Thanks for your
 feedback
 
 But the cache is not taken from a global variable but resolved
 via a local resource.
 
 I am not sure what this local resource is (I am no Apache expert).
 But, I expect that it is virtual host specific.

From what I understand, it is stored as static global (as APR table with
APR mutex control for accessing by threads).

I changed it to use key,map_file_name and it works for me. I have a
writeup at http://www.izpug.org/Members/zeomega/mod_rewrite, for more
information in case you are interested.

thanks,
ganesh

Zeomega LLC
Open minds' Open Solutions

Plano, Texas, USA
Bangalore, India
phone: 972-731-6750
http://www.zeomega.com

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Re: RewriteMaps inefficient (was: [Zope-dev] Apache Mod_rewrite question)

2004-07-15 Thread Dieter Maurer 
Ganesha Shanmuganathan wrote at 2004-7-14 17:26 -0500:
 ...
 Now, we use RewriteMaps only when the map files are very small
 (not more than some dozen entries).
That is interesting to know. Right now, we use multiple map files but
each is small. Is there anyother way to do load balncing with Zope
without Rewrite ?

We use a load balancer (a piece of hardware) for this.

Alternatively, pond (or similar) is a software load balancer
implemented in Python.

 
  ... maps with the same name ...
 The problem is the cache treats both the file as the same since they
 have the same name! Hence if you visit foo.com first, the data stored in
 foomap.txt is returned from the cache next time you visit foo.com or
 bar.com. This causes apache to redirect into the wrong zope site.
 
 We did not observe this behaviour...
btw, Did you use the same map name (like, in different sections maybe)
for the different map files.

Yes. The same map file name mapping to different files in different
virtual hosts.

-- 
Dieter
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Re: [Zope-dev] Apache Mod_rewrite question

2004-07-14 Thread Eugene 
Hello Ganesha,
Wednesday, July 14, 2004, 1:40:14 AM, you wrote:

I'm using mod_rewrite with zope but without maps.
Can your describe in details your task?


GS Hi,

GS I came across a strange behavior of mod_rewrite while using with zope.
GS Although it is not a zope question, I was wondering if any of you have
GS run into this. We are using mod_rewrite to redirect the users to one of
GS the zope sites of a Zeo cluster.

GS The directive RewriteMap has unexpected behavior when it is used to
GS define more than one map with same map name in diffrent places. Normally
GS all the directives within a tag applies only to that tag. 

GS For example:

GS VirtualHost *
GS ServerName   www.foo.com
GS DocumentRoot /var/www/foo
GS RewriteEngine on
GS RewriteLog/var/log/httpd/foo.log
GS RewriteLogLevel  2
GS RewriteMap map rnd:/etc/httpd/conf/foomap.txt
GS RewriteRule ^/Foo(.*)
GS http://127.0.0.1${map:IP}/VirtualHostBase/http/foo/$1 [L,P]
GS /VirtualHost

GS VirtualHost *
GS ServerName   www.bar.com
GS DocumentRoot /var/www/bar
GS RewriteEngine on
GS RewriteLog/var/log/httpd/bar.log
GS RewriteLogLevel  2
GS RewriteMap map rnd:/etc/httpd/conf/barmap.txt
GS RewriteRule ^/Bar(.*)
GS http://127.0.0.1${map:IP}/VirtualHostBase/http/bar/$1 [L,P]
GS /VirtualHost

GS The above is expected to work. However ModRewrite, does not read the map
GS file foomap.txt or barmap.txt everytime it needs it and it caches the
GS results after the first time it reads for faster operation.  

GS The problem is the cache treats both the file as the same since they
GS have the same name! Hence if you visit foo.com first, the data stored in
GS foomap.txt is returned from the cache next time you visit foo.com or
GS bar.com. This causes apache to redirect into the wrong zope site.

GS Has anyone else experienced similar problems ? 

GS thanks,
GS ganesh

GS Zeomega LLC
GS Open minds' Open Solutions

GS Plano, Texas, USA
GS Bangalore, India
GS phone: 972-731-6750
GS http://www.zeomega.com

GS ___
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-- 
Best regards,
 Eugenemailto:[EMAIL PROTECTED]

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Re: [Zope-dev] Apache Mod_rewrite question

2004-07-14 Thread Ganesha Shanmuganathan 
Hi,

We are using mod_rewrite to redirect the incoming requests to one of the
zope instances running on the same machine. It is an SMP machine and has
4 zope instances. The map basically contains
IP port1|port2|port3

Where port1 and port2 etc are the ports where the zope is running. The
problem is mod_rewrite caches the map file based on map name instead of
file as I have mentioned below. But we have solved the problem by using
different map names in each of the VirtualHost sections.


thanks,
ganesh 

Zeomega LLC
Open minds' Open Solutions

Plano, Texas, USA
Bangalore, India
phone: 972-731-6750
http://www.zeomega.com

On Wed, 2004-07-14 at 02:23, Eugene wrote:
 Hello Ganesha,
 Wednesday, July 14, 2004, 1:40:14 AM, you wrote:
 
 I'm using mod_rewrite with zope but without maps.
 Can your describe in details your task?
 
 
 GS Hi,
 
 GS I came across a strange behavior of mod_rewrite while using with zope.
 GS Although it is not a zope question, I was wondering if any of you have
 GS run into this. We are using mod_rewrite to redirect the users to one of
 GS the zope sites of a Zeo cluster.
 
 GS The directive RewriteMap has unexpected behavior when it is used to
 GS define more than one map with same map name in diffrent places. Normally
 GS all the directives within a tag applies only to that tag. 
 
 GS For example:
 
 GS VirtualHost *
 GS ServerName   www.foo.com
 GS DocumentRoot /var/www/foo
 GS RewriteEngine on
 GS RewriteLog/var/log/httpd/foo.log
 GS RewriteLogLevel  2
 GS RewriteMap map rnd:/etc/httpd/conf/foomap.txt
 GS RewriteRule ^/Foo(.*)
 GS http://127.0.0.1${map:IP}/VirtualHostBase/http/foo/$1 [L,P]
 GS /VirtualHost
 
 GS VirtualHost *
 GS ServerName   www.bar.com
 GS DocumentRoot /var/www/bar
 GS RewriteEngine on
 GS RewriteLog/var/log/httpd/bar.log
 GS RewriteLogLevel  2
 GS RewriteMap map rnd:/etc/httpd/conf/barmap.txt
 GS RewriteRule ^/Bar(.*)
 GS http://127.0.0.1${map:IP}/VirtualHostBase/http/bar/$1 [L,P]
 GS /VirtualHost
 
 GS The above is expected to work. However ModRewrite, does not read the map
 GS file foomap.txt or barmap.txt everytime it needs it and it caches the
 GS results after the first time it reads for faster operation.  
 
 GS The problem is the cache treats both the file as the same since they
 GS have the same name! Hence if you visit foo.com first, the data stored in
 GS foomap.txt is returned from the cache next time you visit foo.com or
 GS bar.com. This causes apache to redirect into the wrong zope site.
 
 GS Has anyone else experienced similar problems ? 
 
 GS thanks,
 GS ganesh
 
 GS Zeomega LLC
 GS Open minds' Open Solutions
 
 GS Plano, Texas, USA
 GS Bangalore, India
 GS phone: 972-731-6750
 GS http://www.zeomega.com
 
 GS ___
 GS Zope-Dev maillist  -  [EMAIL PROTECTED]
 GS http://mail.zope.org/mailman/listinfo/zope-dev
 GS **  No cross posts or HTML encoding!  **
 GS (Related lists - 
 GS  http://mail.zope.org/mailman/listinfo/zope-announce
 GS  http://mail.zope.org/mailman/listinfo/zope )
 
 

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RewriteMaps inefficient (was: [Zope-dev] Apache Mod_rewrite question)

2004-07-14 Thread Dieter Maurer 
Ganesha Shanmuganathan wrote at 2004-7-13 16:40 -0500:
 ...
The directive RewriteMap has unexpected behavior when it is used to
define more than one map with same map name in diffrent places. Normally
all the directives within a tag applies only to that tag. 

There are more strange things with Apache's RewriteMaps.
Be warned: they are very inefficiently implemented for large maps!

  We used such maps to let Apache serve static CMF content
  as folkore reports that Apache is an order of magnitude
  faster than Zope in serving static content.

  It turned out that the solution using Apache RewriteMaps was 
  slower than directly serving this content from Zope --
  by a factor of 5!

  The explanation: Apache caches only single successful lookups
  in the map file. Each access to a key not in the cache
  results in parsing the map file until the key is found -- the
  whole map file when it does not contain the key.
  For larger map files, this has desastrous effects.

Now, we use RewriteMaps only when the map files are very small
(not more than some dozen entries).

 ... maps with the same name ...
The problem is the cache treats both the file as the same since they
have the same name! Hence if you visit foo.com first, the data stored in
foomap.txt is returned from the cache next time you visit foo.com or
bar.com. This causes apache to redirect into the wrong zope site.

We did not observe this behaviour...

-- 
Dieter
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[Zope-dev] Apache Mod_rewrite question

2004-07-13 Thread Ganesha Shanmuganathan 
Hi,

I came across a strange behavior of mod_rewrite while using with zope.
Although it is not a zope question, I was wondering if any of you have
run into this. We are using mod_rewrite to redirect the users to one of
the zope sites of a Zeo cluster.

The directive RewriteMap has unexpected behavior when it is used to
define more than one map with same map name in diffrent places. Normally
all the directives within a tag applies only to that tag. 

For example:

VirtualHost *
ServerName   www.foo.com
DocumentRoot /var/www/foo
RewriteEngine on
RewriteLog/var/log/httpd/foo.log
RewriteLogLevel  2
RewriteMap map rnd:/etc/httpd/conf/foomap.txt
RewriteRule ^/Foo(.*)
http://127.0.0.1${map:IP}/VirtualHostBase/http/foo/$1 [L,P]
/VirtualHost

VirtualHost *
ServerName   www.bar.com
DocumentRoot /var/www/bar
RewriteEngine on
RewriteLog/var/log/httpd/bar.log
RewriteLogLevel  2
RewriteMap map rnd:/etc/httpd/conf/barmap.txt
RewriteRule ^/Bar(.*)
http://127.0.0.1${map:IP}/VirtualHostBase/http/bar/$1 [L,P]
/VirtualHost

The above is expected to work. However ModRewrite, does not read the map
file foomap.txt or barmap.txt everytime it needs it and it caches the
results after the first time it reads for faster operation.  

The problem is the cache treats both the file as the same since they
have the same name! Hence if you visit foo.com first, the data stored in
foomap.txt is returned from the cache next time you visit foo.com or
bar.com. This causes apache to redirect into the wrong zope site.

Has anyone else experienced similar problems ? 

thanks,
ganesh

Zeomega LLC
Open minds' Open Solutions

Plano, Texas, USA
Bangalore, India
phone: 972-731-6750
http://www.zeomega.com

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