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From Niklas Edmundsson <>
Subject Re: [PATCH] mod_disk_cache working LFS (filecopy)
Date Wed, 27 Sep 2006 09:07:44 GMT
On Tue, 26 Sep 2006, Graham Leggett wrote:

> Niklas Edmundsson wrote:
>> * Realising that a file is a file and can be copied as such, without
>>   reading the whole thing into memory first.
>> * When a file is cached by copying, replace the brigade with a new one
>>   refering to the cached file so we don't have to read the file from
>>   the backend again when sending a response to the client.
> As I read the code, the copy is completed before an attempt is made to 
> deliver the copy to the network. This should in theory stop a slow initial 
> client from holding up faster following clients, if the caching is still "in 
> transit".
> Is this correct?

This is the original design of mod_disk_cache (which isn't changed by 
this patch), so yes.

In practice this isn't enough when dealing with large files, so in our 
production code (the hideously large jumbopatch) this is fixed by 
read-while-caching and spawning a thread to do the caching in the 
background while delivering the response (by read-while-caching) to 
the client that initiated the caching.

  Niklas Edmundsson, Admin @ {acc,hpc2n}      |
  "Why don't you go teach someone who actually needs to learn?!" - Buffy

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