[squid-users] server persistent connections and cache

[Alex Rousskov]

On 07/18/2018 03:03 PM, Vishali Somaskanthan wrote:

> I had a problem after sending too many requests to the same server where
> my persistence stopped working suddenly.

Please note that there are many reasons why a proxy may close a
connection. For pinned to-server connections (like those created by
SslBump), it may not be possible to open a new to-server connection so
Squid should close both from-client and to-server connections.

In general, a client should not rely on a connections staying persistent
except in some very unusual/special circumstances.


> 1. What is the relationship between the caching and the persistence
> connection established?

Virtually none. Caching decisions are done primarily based on request
and response headers.


> 2. When will squid use cached results and when will it not if the cache
> deny all directive weren't specified. 

Squid will deliver a response from the cache when HTTP rules and Squid
configuration allow a hit. The details are too complex to document here.


> 3. However, this didn't work fully. Even with /cache deny all/
> directive, persistence wasn't working when I peeked at the sslBump step
> 1 and then Bumped. 
> Persistence worked only when I directly did sslbump allow all (without
> peeking at first step).

Bumping step should not affect connection persistence AFAICT. I do not
know why it does in your case. This could be a Squid bug or a
misunderstanding. If you can reproduce, Squid logs should contain
reasons for each connection closure (but it may be difficult to find).


HTH,

Alex.