Squid cache codes refer to requests on the HTTP port (usually 3128).

TCP_HIT

A valid copy of the requested object was in the cache.

TCP_MISS

The requested object was not in the cache.

TCP_REFRESH_HIT

The requested object was cached but STALE. The IMS query for the object resulted in "304 not modified".

TCP_REF_FAIL_HIT

The requested object was cached but STALE. The IMS query failed and the stale object was delivered.

TCP_REFRESH_MISS

The requested object was cached but STALE. The IMS query returned the new content.

TCP_CLIENT_REFRESH_MISS

The client issued a "no-cache" pragma, or some analogous cache control command along with the request. Thus, the cache has to refetch the object.

TCP_IMS_HIT

The client issued an IMS request for an object which was in the cache and fresh.

TCP_SWAPFAIL_MISS

The object was believed to be in the cache, but could not be accessed.

TCP_NEGATIVE_HIT

Request for a negatively cached object, e.g. "404 not found", for which the cache believes to know that it is inaccessible. Also refer to the explainations for negative_ttl in your squid.conf file.

TCP_MEM_HIT

A valid copy of the requested object was in the cache and it was in memory, thus avoiding disk accesses.

TCP_DENIED

Access was denied for this request.

TCP_OFFLINE_HIT

The requested object was retrieved from the cache during offline mode. The offline mode never validates any object, see offline_mode in squid.conf file.

UDP_HIT

A valid copy of the requested object was in the cache.

UDP_MISS

The requested object is not in this cache.

UDP_DENIED

Access was denied for this request.

UDP_INVALID

An invalid request was received.

UDP_MISS_NOFETCH

During "-Y" startup, or during frequent failures, a cache in hit only mode will return either UDP_HIT or this code. Neighbours will thus only fetch hits.

NONE

Seen with errors and cachemgr requests.

The following codes are no longer available in Squid-2:

ERR_*

Errors are now contained in the status code.

TCP_CLIENT_REFRESH

See: TCP_CLIENT_REFRESH_MISS.

TCP_SWAPFAIL

See: TCP_SWAPFAIL_MISS.

TCP_IMS_MISS

Deleted, TCP_IMS_HIT used instead.

UDP_HIT_OBJ

Hit objects are no longer available.

UDP_RELOADING

See: UDP_MISS_NOFETCH.