Re: [squid-users] About Cache Digest

From: Henrik Nordstrom <>
Date: Mon, 07 Apr 2008 10:43:44 +0200

mån 2008-04-07 klockan 11:44 +0800 skrev Zhou, Bo(Bram):

> 1. How often local host fetch the digest from peers?

Each digest_rebuild_period as set by the peer.

> Any timer controls or
> just checks if the cache digests are expired? Some hard-coded timers,
> PeerDigestReqMinGap and GlobDigestReqMinGap in peer_digest.c, are defined in
> the source codes, what's purpose of these timers? When will these timers be
> started and stopped?

These are safeguards to make sure digest fetching doesn't suck up too
much bandwidth, in case the peer(s) is badly configured.

> 2. For digest_rebuild_chunk_percentage, if I define it 10%, does that mean
> Squid will add more 10% cache to digest for each digest_rebuild_period
> interval or within digest_rebuild_period interval but finish processing
> other user requests?

It's how much of the cache Squid should digest at a time when rebuilding
the cache digest. No requests is processed while this is done, only very
briefly between chunks.

Hmm.. not even sure why this directive exists. I think it should scan
one bucket at a time.. digest rebuilding is not a very high priority
item and blocking request forwarding for this is not good...

Alex: do you remember why this directive was added?

Received on Mon Apr 07 2008 - 02:45:26 MDT

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