Re: [squid-users] High tcp_hit times

On fre, 2008-06-06 at 14:38 -0700, leongmzlist wrote:
> My cache performance is acting strange; I'm getting extremely high
> tcp_hit times for cached objects:
>
> 1212787643.465 50343 10.2.7.22 TCP_HIT/200 19290 GET http://cache-int/....
> 1212787737.740 15212 10.2.7.25 TCP_HIT/200 11511 GET http://cache-int/....
>
>
> Those high times comes in bursts. Eg: bunch of high response time
> will come followed by a normal response times. Normal response times
> are sub 100ms

Could be cache validations. Some times TCP_HIT is logged when it really
should have been TCP_REFRESH_HIT. This can happen if the object uses
Vary if I remember correctly.

Another possibility is if the Squid serer is swapping, causing Squid to
delay everything waiting for swap activity.

A third possibility is if you have ACLs which may cause delays, such as
DNS dependencies or external acl lookups.

Regards
Henrik
Received on Fri Jun 06 2008 - 22:10:29 MDT