Modified excel sheet in docroot is taking time to reflect if in URL

[IamRasheed]

Hi,

First of all, I apologize because i already asked such a question but that time i couldnt able to come online again.
Now i am not able update the question, hence asking again. please help me in resolving this.

I need a help in resolving one issue in our environment. We have many webservers in our environment, Few webservers serves static contents. In one application, we often change the excel file. Every day or 2 days once we will modified the excel sheet content. FIle name will be teh same, only the content will be changed. We will modify the content of the sheet and upload through FTP to the docroot. After we done this if we access the application URL, its displaying the old content. Its takes time to reflect. sometime with in 3 hours sometimes after a day only reflecting. We are not sure what is the issue.

we cleared the cache in browser and tried then also its showing the old content. We are using DNS,network load balancer, proxy between the browser and the webserver.

I tired accessing through FQDN, it showed old content, then i accessed through the LB IP it showed the modifed file. For testing i changed the content again and then accessed. This time even for IP it showed old content. Same i tried with the instance 1 IP and Instance 2 IP. On first time it showing properly but after i cahnged the file content and accessed it showing the old file

I tried accesing from a different PC where we havent accessed before, there also it showed old content, SO i feel browser cache is not an issue.

We using Source subnet mask IP persistence in load balancer. I am not sure where the old file is cached actually. Will it be cached in Load balancer or proxy or somewhere in webserver.

Could some one please help me on this?

[lucy24]

SO i feel browser cache is not an issue.
...
a different PC where we havent accessed before

Server and browser are simply the beginning and end of a trip that might have several legs with several possible cache points. What happens along the way?

What do the assorted cache-control headers say? That's assuming everyone on your route can be trusted to obey headers.

:: insert boilerplate about notorious local ISP that has been known to send out material that should never have been cached at all, like individual users' login pages, to other users ::

[IamRasheed]

I am sorry i am not have much technical knowledge.

What do the assorted cache-control headers say? That's assuming everyone on your route can be trusted to obey headers.

=> We didnt add any entry like cache-control in httpd.conf file.
Please let me know where should i check this.

:: insert boilerplate about notorious local ISP that has been known to send out material that should never have been cached at all, like individual users' login pages, to other users ::

=> application team is not using any code or language.
we jsut made the DOCRoot as

DocumentRoot "/nas/instance/apache/docroots/instance0/sslhtdocs"
<Directory "/nas/instance/apache/docroots/instance0/sslhtdocs">
Options Includes FollowSymLinks MultiViews
AllowOverride All
Order allow,deny
Allow from all
</Directory>

the files will be placed in the DocRoot and it will be access like below
http(s)://abc.xyz.com/directory/file.xls
when we access this URL, we will get a dialog box to save or open, if we save or open, we will be getting the old file instead of modified file.

[phranque]

use a header checker to see what HTTP Response headres you are getting when you request that resource.

for example - Check HTTP Response Headers Tool:
http://freetools.webmasterworld.com/tools/fetch-header/ [freetools.webmasterworld.com]

look for any headers such as:
- Expires:
- Cache-Control:
- Etag:
- Date:
- Pragma:

[lucy24]

There are two separate questions:

-- is everyone doing what the site tells them to do
-- is the site telling them to do something

Before you can start faulting anyone for excessive caching, make sure you are in fact telling them not to cache.

Also do a ping or traceroute to see exactly where the file has been. I doubt there's a direct cable running straight from your server to your computer with no stops.

[tangor]

A low tech way to get some answers:

To find out if the server where the xls file is located is holding a cached copy, change the xls file. Access it from another machine with permissions. If showing old xls. Reboot machine holding the xls file. After it is up access the xls file. If it shows immediately the new xls then you might want to look at the config files on that machines. If there is a server above that machine, try the same thing. All this will show is that something is cached and it might show where to look.

[IamRasheed]

Hi phranque,

I am not able to use the tool,you given because the server is inside the firewall. I used the Live HTTP Header extension of firefox and accessed the application. I got the below information

http://abc.xyz.co.jp/j/iris/Cachetest.xls

GET /j/iris/Cachetest.xls HTTP/1.1
Host: abc.xyz.co.jp
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:30.0) Gecko/20100101 Firefox/30.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Connection: keep-alive

HTTP/1.1 200 OK
Date: Thu, 03 Jul 2014 04:00:30 GMT
Server: Apache
Last-Modified: Thu, 03 Jul 2014 03:00:21 GMT
Etag: "dae2-4400-359c9b40"
Accept-Ranges: bytes
Keep-Alive: timeout=15, max=100
Content-Length: 17408
Content-Type: application/vnd.ms-excel
X-RBT-Optimized-By: sen-htb6050-wpa1 (RiOS 8.5.0) PT
Connection: Keep-Alive
Age: 24


Hi lucy24,

"make sure you are in fact telling them not to cache"

==>Please kindly help me how to do this

Its not a direct cable from server to PC. Server located in Japan, and users are from japan as well as singapore.
We have DNS,Network load balancer in between. I accessed the application using proxy as well as without proxy.
First time if i access the application using the FQDN, i am getting the current file. Later i change the file and access its not showing the updated file.
Then i access the file by using the IP http://<IP>/directory/file.xls , it shows the modified file(because first time accessing from IP). Then i changed the file content again and accessed using FQDN as well as IP its not showing the modified file.
Using FQDN it shows the very old file, Using IP it shows teh old file. Now if i access in different way by disabling the proxy, i'll get the modified file.
But if i modified teh file again, then this time even if i accesing without proxy also it wont display the modified file.

That is , if we access the file in a new way for the first time we will get the modified file. But if we change the file and accesing the same way it wont work.


Hi tangor,

As you said, i accessed the modified file from a new PC, it showed the old file. Then i restarted the apache and accessed again but i could see only the old file. I am not able to see the new modified file.

[edited by: phranque at 12:04 pm (utc) on Aug 8, 2014]
[edit reason] unlinked URLs [/edit]

[phranque]

i would expect to find the problem in the riverbed steelhead appliance.

http://h20566.www2.hp.com/portal/site/hpsc/template.PAGE/public/kb/docDisplay?docId=mmr_kc-0108473&ac.admitted=1404398031766.876444892.199480143 [h20566.www2.hp.com]:

When an HTTP connection is optimized by a Steelhead appliance, the HTTP header shows the entry: "X-RBT-OPTIMIZE-BY" along with some codes.

[IamRasheed]

I am sorry, i am not aware much on this.
COuld you please kindly tell me what i have to do?

[tangor]

Take a look at this.... The how=to cache Apache server...

This document supplements the mod_cache, mod_disk_cache, mod_mem_cache, mod_file_cache and htcacheclean reference documentation. It describes how to use Apache's caching features to accelerate web and proxy serving, while avoiding common problems and misconfigurations.

[httpd.apache.org...]
This for Apache 2.2, but useful for all versions.

[IamRasheed]

Thank you for sharing.
I'll check the same.