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
