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From Graham Leggett <>
Subject Re: strange usage pattern for child processes
Date Wed, 15 Oct 2008 20:26:06 GMT
Lars Eilebrecht wrote:

> The second odd thing is that the connections/threads in W state
> seem to be hanging, i.e., no data is being transferred over the
> connection and these threads/connection time out after about 256
> seconds. However, the general Timeout setting is 30s so why
> isn't the connection killed after 30s?

Something else to try is to look at the ProxyIOBufferSize parameter.

The proxy reads from the backend in blocks, and as soon as a block is 
not full (ie it's the last block), the proxy will complete and terminate 
the backend request before sending the last block on to the client.

If the request is small enough to fit into a single block (or if the 
buffer size is big enough for a bigger request to fit), what this means 
is that a slow client on the front end will not hold up the backend, 
which will be released immediately.

In theory, setting the buffer size larger on the caches will release the 
origin backends earlier, and setting the buffer size larger on proxies 
before the cache will release the caches earlier.


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