Hi again,
the problem seems to be in the proxy.
When proxy read the data and pass it to output filter, it do:
while (ap_get_brigade){
ap_pass_brigade(output_filter)
}
si if the data aren't read by only one brigade, the mod_cache can't work.
because it will try to cache only the first brigade with a part of data.
Do you think it's better to modify how proxy is passing data to the
output_filter
or to modify the way mod_cache is getting his data from bucket_brigade ?
Matthieu
Matthieu Estrade wrote:
> Hi,
>
> i'am working on mod_cache and mod_mem_cache + mod_proxy
> i found a problem with EOS Bucket.
>
> mod_cache is inserting his cache_in filter in output_filter when he
> wants to insert data in the cache.
> when mod_cache is used with mod_proxy, the cache_in filter is called
> after mod_proxy call ap_pass_brigade in the
> ap_proxy_http_process_response, after received data from backend server.
>
> when i do test on a website, sometimes, i can see my file is not
> cached because length > MaxStreamingBuffer.
> when i put a debug on the MaxStreamingBuffer value, i always get 0
> even if i setup in my httpd.conf another value with
> CacheMaxStreamingBuffer.
> So maybe a first bug here.
>
> But the problem doesn't come from this bug.
>
> When i process my test, i can see that some files are not cached
> because of this error, so i put debug in the function calculating the
> length of data to be cached in mod_cache.
> And something really strange happen, strange for me, but maybe not for
> you....
>
> what happen:
>
> APR_BRIGADE_FOR_EACH(e,in){
>
> look if bucket is eos, if yes, exit with all_bucket_here=1
> or: look if bucket is flush, if yes, exit with unresolved_length=1
> or: size += e->length;
>
> }
>
> on the file not cached because the MaxStreamingBuffer error, the code
> above never detect a EOS bucket, so, it return a size to the following
> code:
>
> if (!all_bucket_here){
> if (unresolved_length || size > MaxStreamingBuffer)
> exit with MaxStreamingBuffer Error.
> }
>
> Where it's really strange, is i put a debug in mod_proxy, when it
> receive the data from backend server, and before passing the brigade
> to the output_filter, i can detect a EOS Bucket.
> So, i have a EOS Bucket found in the brigade mod_proxy will pass to
> output_filter, and in the filter reading the same brigade in mod_cache
> (cache_in filter), i can't find this same EOS Bucket.
>
> if someone have an idea :)
> i will continue to search on that.
>
> Best regards,
>
> Estrade Matthieu
>
>
>
>
