Is LCI on the radar?

Lukas Kahwe Smith mls at
Mon Jun 27 19:22:05 CEST 2011

On 27.06.2011, at 17:45, Laurence Rowe wrote:

> This type of purge (which in Varnish 3 is renames 'ban') adds the
> expression to the ban list. When any object is found in the cache the
> expressions in the ban list are checked to decide whether to call
> vcl_hit or vcl_miss. To prevent the ban list getting too long another
> thread periodically works its way through all objects in the cache
> removing those that have been banned and updating the pointer to the
> place in the ban list it has checked so on subsequent requests fewer
> ban expressions need to be checked.

Ok, that sounds pretty much like genius to me :)

> I've not done any benchmarking on this, but for me even thousands of
> regular expression checks will be much faster than re-requesting the
> page from the CMS. So with my Varnish config, a PURGE request is cheap
> (it only results in adding an entry to the ban list, not checking
> against the entire contents of the cache) and the additional cost of
> checking each GET request is not noticeable. So I don't really see the
> need for LCI support given the existing support for bans.

well LCI support would just mean Varnish plays along with a published standard for this kind of feature, which is always a plus.

Lukas Kahwe Smith
mls at

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