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

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)

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 - 17:46:33 MDT