Re: [squid-users] Re: Squid Cache flush

On 21/04/2011 1:46 PM, Jawahar Balakrishnan (JB) wrote:
> If you are thinking that is is dynamic content with query strings then
> it's not the case. the urls will look like a directory structured
> static content but the back-end app server will translate the url and
> fetch the appropriate content from the CMS (alfresco)
>
Very few CMS or portals use query strings to select content.
Our portal does not.

What software are you using? Perhaps you can get some actual experience
from a current squid user.

Have you tried a test with squid?

Ron
> On Thu, Apr 21, 2011 at 1:30 PM, Ron Wheeler
> <rwheeler_at_artifact-software.com> wrote:
>> If you google "squid dynamic content" you will find that by default squid
>> does not cache dynamic content.
>> If it did, it would be useless as a proxy server since that would make
>> almost all dynamic sites unusable.
>>
>> There are lots of instructions about how to trick squid into caching content
>> that it (and the web servers it proxies) think is dynamic but you know is
>> not.
>> Youtube videos is one example where the web server says the content is
>> dynamic but in fact humans know that it is not.
>>
>> I think that a simple test will allow you to see that your CMS content will
>> get handled correctly.
>>
>> What are you using for CMS servers?
>> Perhaps someone can give you first-hand experience or a web site to visit.
>> I have never had to do anything to Apache and Wordpress to get it to work
>> properly.
>>
>> Don't forget that Squid and the web server can talk to each other without
>> actually shipping content. The HTTP protocol has lots of different messages
>> that can be quickly exchanged to make decisions about whether squid actually
>> needs new content.
>>
>>
>> Ron
>>
>>
>> On 21/04/2011 12:31 PM, Jawahar Balakrishnan (JB) wrote:
>>> It is all dynamic content going forward
>>>
>>> scenarios where a cache flush would be required
>>>
>>> 1) an article is updated
>>> 2) category is updated with a list of articles.
>>>
>>> we syndicate content to abut 150 partner and will have same
>>> article/category with a different URL doesn't squid cache based on the
>>> url?
>>>
>>> when you update content on your cms - how does squid know to update it's
>>> cache?
>>>
>>> JB
>>>
>>> On Thu, Apr 21, 2011 at 12:10 PM, Ron Wheeler
>>> <rwheeler_at_artifact-software.com> wrote:
>>>> Are you sure that you need to do this?
>>>> Squid should be able to tell the difference between static and dynamic
>>>> content.
>>>>
>>>> We have a dynamic JSR-168/268 portal based on Tomcat and Jetspeed sitting
>>>> behind Apache and Squid and we have never had to intervene with Squid
>>>> for 3
>>>> years.
>>>> We also have lots of Wordpress CMS sites.
>>>>
>>>> The user gets the latest information on every page load regardless of the
>>>> URL being the same.
>>>>
>>>> What exactly would cause you to trigger a flush of the cache?
>>>>
>>>> Ron
>>>>
>>>>
>>>> On 21/04/2011 11:30 AM, Jawahar Balakrishnan (JB) wrote:
>>>>> I would rather not do a restart of anything unless absolutely required
>>>>>
>>>>> Here are the challenges we face
>>>>>
>>>>> 1) We are trying to deploy Suqid as a reverse-proxy in front of a CMS
>>>>> 2) We want to trying find a balance between keeping the content fresh
>>>>> without affecting performance by frequently expiring content.
>>>>>
>>>>> Our current reverse proxy solution allow us to flush the entire cache
>>>>> without having to restart but in limited testing Squid seemed to
>>>>> perform much better and we would prefer to use Squid but still retain
>>>>> the functionality of being able to flush the entire cache periodically
>>>>> via cron or when in case of an emergency.
>>>>>
>>>>> Cache-control headers are fine and will work in case of limited number
>>>>> of objects.
>>>>>
>>>>> Thanks
>>>>> JB
>>>>>
>>>>>
>>>>> On Tue, Apr 19, 2011 at 7:27 PM, Amos Jeffries<squid3_at_treenet.co.nz>
>>>>> wrote:
>>>>>> On Tue, 19 Apr 2011 11:14:55 -0400, Jawahar Balakrishnan (JB) wrote:
>>>>>>> I am looking to deploy Squid as a reverse proxy and i had couple of
>>>>>>> questions. We currrently use Bluecoat and Sun Web proxy and i am able
>>>>>>> to do the following things
>>>>>>>
>>>>>>> 1) How would i flush objects from cache?
>>>>>> The whole lot:
>>>>>> http://wiki.squid-cache.org/SquidFaq/ClearingTheCache
>>>>>>
>>>>>> or individually via:
>>>>>> HTTP "PURGE" requests
>>>>>> HTCP "CLR" requests
>>>>>>
>>>>>> squidpurge tool commands.
>>>>>>
>>>>>>
>>>>>>> 2) Can i flush the entire cache without restarting Squid?
>>>>>> Yes ... but it takes a LONG time to do N objects individually.
>>>>>> Restart without a cache to load takes milliseconds.
>>>>>>
>>>>>>> 3) Can i set the configuration to expire objects at a certain time
>>>>>>> every day regardless of when the object was cache during the previous
>>>>>>> 24 hours?
>>>>>> Use of the Expiry and Cache-Control mechanisms properly can do just
>>>>>> about
>>>>>> anything. Correct use will make all proxies not just your reverse one
>>>>>> handle
>>>>>> the site fine and remove a lot of customer problems.
>>>>>>
>>>>>> Objects which arrive with header "Expires: XX" will expire at XX
>>>>>> timestamp
>>>>>> and be replaced on their next use.
>>>>>>
>>>>>>
>>>>>>
>>>>>> Amos
>>>>>>
>>>>>>
>>
Received on Thu Apr 21 2011 - 21:29:49 MDT