Re: Patch mod_proxy: mod_proxy + mod_cache problem
Ian Holsman wrote: The cache filter is supposed to run after all the filters for maximum caching advantage. I disagree on this. the cache filter should be able to placed where the admin wants it. In the advanced case, yes - but in the simplest turn-it-on-and-it-should-just-work case the cache should be as optimised as possible. what the code should do is remember which filters where placed above the cache_input filter, and restore these filters on cache_output. This starts getting complex. The original idea for the cache was to be transparent public proxy cache layered between Apache and the browser. Because RFC2616 dictates how such a proxy cache should work, determining whether we have done the right thing should be relatively easy. As we move the caching filters further towards the core of Apache, suddenly things start to get complicated, as there is no longer a guarantee that the point into which cache has been inserted is compliant with RFC2616 in the first place, which in turn makes things less likely to work predictably or correctly. Yes, being able to put the cache wherever the admin wants is in theory a nice thing to have, actually practically achieving this is something that's going to have to be looked at pretty carefully. Regards, Graham -- - [EMAIL PROTECTED]There's a moon over Bourbon Street tonight...
RE: Patch mod_proxy: mod_proxy + mod_cache problem
Hi again :) I did a patch modifiying mod_proxy to pass the entire data (response from backend server) to output_filter, unstead of brigade per brigade. One comment (having not reviewed the patch): Proxy should stream bytes from the backend server to the client as those bytes arrive. Proxy should not require that the entire response from the backend be received before writing to the client. Bill
Re: Patch mod_proxy: mod_proxy + mod_cache problem
Matthieu Estrade wrote: I did a patch modifiying mod_proxy to pass the entire data (response from backend server) to output_filter, unstead of brigade per brigade. AFAIK the problem stems from a limitation in mod_cache where it can only cache stuff in a single brigade at the moment. Proxy works correctly already - there is no such thing as pass the entire data, because there is no way for proxy to know just how much data there is in advance, and there is no guarantee that data will all fit in memory at once. Regards, Graham -- - [EMAIL PROTECTED]There's a moon over Bourbon Street tonight...
Re: Patch mod_proxy: mod_proxy + mod_cache problem
hi bill, I agree with you about the proxy... Do you think it's possible to force the cache filter, be runned after all the proxy filters ? Matthieu Bill Stoddard wrote: Hi again :) I did a patch modifiying mod_proxy to pass the entire data (response from backend server) to output_filter, unstead of brigade per brigade. One comment (having not reviewed the patch): Proxy should stream bytes from the backend server to the client as those bytes arrive. Proxy should not require that the entire response from the backend be received before writing to the client. Bill
Re: Patch mod_proxy: mod_proxy + mod_cache problem
Matthieu Estrade wrote: I agree with you about the proxy... Do you think it's possible to force the cache filter, be runned after all the proxy filters ? The cache filter is supposed to run after all the filters for maximum caching advantage. Regards, Graham -- - [EMAIL PROTECTED]There's a moon over Bourbon Street tonight...
Re: Patch mod_proxy: mod_proxy + mod_cache problem
Hi graham, the problem is the filter is called between two ap_pass_brigade by the reverse proxy... like: proxy: get_brigade (data from backend) pass_brigade(pass data to outputfilter) cache_filter get_brigade(data from backend) pass_brigade(pass_data_to outputfilter) on one response by the backend server. regards, Matthieu Graham Leggett wrote: Matthieu Estrade wrote: I agree with you about the proxy... Do you think it's possible to force the cache filter, be runned after all the proxy filters ? The cache filter is supposed to run after all the filters for maximum caching advantage. Regards, Graham
Re: Patch mod_proxy: mod_proxy + mod_cache problem
Actually, the problem is in the fact that there is more than one brigade and the cache code can't currently handle that. Proxy is working the way it is supposed to. This allows Apache to process large responses without having to buffer the whole thing inside Apache. Apache uses less memory, and the user starts seeing results sooner. If proxy were to process all of the brigades of a large response before the next filter were allowed access, then proxy could potentially buffer a *huge* amount of data. The answer is that the cache code currently only caches responses that arrive in one brigade. Proxy isn't the problem. Matthieu Estrade wrote: Hi graham, the problem is the filter is called between two ap_pass_brigade by the reverse proxy... like: proxy: get_brigade (data from backend) pass_brigade(pass data to outputfilter) cache_filter get_brigade(data from backend) pass_brigade(pass_data_to outputfilter) on one response by the backend server. regards, Matthieu Graham Leggett wrote: Matthieu Estrade wrote: I agree with you about the proxy... Do you think it's possible to force the cache filter, be runned after all the proxy filters ? The cache filter is supposed to run after all the filters for maximum caching advantage. Regards, Graham -- Paul J. Reder --- The strength of the Constitution lies entirely in the determination of each citizen to defend it. Only if every single citizen feels duty bound to do his share in this defense are the constitutional rights secure. -- Albert Einstein
Re: Patch mod_proxy: mod_proxy + mod_cache problem
Graham Leggett wrote: Matthieu Estrade wrote: I agree with you about the proxy... Do you think it's possible to force the cache filter, be runned after all the proxy filters ? The cache filter is supposed to run after all the filters for maximum caching advantage. I disagree on this. the cache filter should be able to placed where the admin wants it. what the code should do is remember which filters where placed above the cache_input filter, and restore these filters on cache_output. this would allow people to have pages designed for a specific user, as well as caching most of it Regards, Graham
Re: Patch mod_proxy: mod_proxy + mod_cache problem
Hi Paul, I know about mod_cache is only working on one brigade, but my problem is not here. My problem is i can't setup the filter cache_in_filter to be executed after mod_proxy pass his last brigade to the filter chain Actually, mod_cache_filter_in is executed only one time when mod_proxy have passed the first brigade to the output_filters. So the others brigade containing data are not available. so, have i to consider that cache_filter_in will have to be able to cache document in many times process, Or is it possible to think that the cache_filter could be placed when mod_proxy finished to pass the last brigade, reading all the brigade and cache it ? regards, Matthieu Paul J. Reder wrote: Actually, the problem is in the fact that there is more than one brigade and the cache code can't currently handle that. Proxy is working the way it is supposed to. This allows Apache to process large responses without having to buffer the whole thing inside Apache. Apache uses less memory, and the user starts seeing results sooner. If proxy were to process all of the brigades of a large response before the next filter were allowed access, then proxy could potentially buffer a *huge* amount of data. The answer is that the cache code currently only caches responses that arrive in one brigade. Proxy isn't the problem. Matthieu Estrade wrote: Hi graham, the problem is the filter is called between two ap_pass_brigade by the reverse proxy... like: proxy: get_brigade (data from backend) pass_brigade(pass data to outputfilter) cache_filter get_brigade(data from backend) pass_brigade(pass_data_to outputfilter) on one response by the backend server. regards, Matthieu Graham Leggett wrote: Matthieu Estrade wrote: I agree with you about the proxy... Do you think it's possible to force the cache filter, be runned after all the proxy filters ? The cache filter is supposed to run after all the filters for maximum caching advantage. Regards, Graham
