Natterings about history files
rra at stanford.edu
Sat Mar 3 21:30:34 UTC 2001
Forrest J Cavalier <mibsoft at epix.net> writes:
> I estimate, but have not measuered, that most of the requests by message
> ID come from the referrer header. That means it is likely that the
> message is in the current newsgroup.
> Does nnrpd check the current newsgroup before doing a history lookup? I
> thought it used to, but I don't recall.
I don't *think* so... let me check. Nope, it goes directly to a history
> That is what I meant by looking up the message ID in overview. Even a
> linear probe of 1000 messages (probably already in memory) is going to
> be way faster than an open of 2 day-history files.)
Hm. You think so? That's somewhat counterintuitive to me. On one hand
you've got a linear walk of all the overview data in the newsgroup and on
the other hand you've got 2x (open/seek/read) per history file.
Admittedly, open is really expensive as system calls go....
Anyway, I think the majority of message ID lookups are probably coming
from NEWNEWS clients on those servers that have enabled NEWNEWS. But I
haven't measured either. :)
Russ Allbery (rra at stanford.edu) <http://www.eyrie.org/~eagle/>
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