[Pan-users] Re: Re: Re: What is "Score"

[Duncan]

Travis posted <address@hidden>, excerpted below,
on Tue, 30 Aug 2005 23:53:43 -0700:

> From: "Lenny Nero"
> 
>> I have been running the same >900 MB db for all of this year, it runs
>> 24/7 with 30+ big groups doing more than 2 gig a day. The only time I
>> stop it is to dfrag the db or to try some new settings.
> 
> What does this mean?  What data base.  How do you defrag a data base?

Presumably the db that tracks what each group on each server has.

Again, presumably, "defrag" refers to "compaction".  Traditionally, a
database doesn't recover the space used by deleted records immediately. In
the interest of efficiency, it simply marks that slot as vacant, not
shrinking the database down to fill the hole, until compaction.  Then, it
removes the holes all at once.

In a very active database such as a newsgroup's active message list, with
new messages being added and old ones expiring at roughly the same rate
over time, each time a message expires that means a deletion, and thus a
hole in the database, until compaction.  Thus, db compaction would need to
be done fairly regularly (to prevent the db getting too bloated with
unreclaimed deletion holes) as compared to, say, the database for a
corporate address list, which would be far less active and for a fair
amount of its life have fewer deletions than additions, and a *FAR* higher
simple access rate, as opposed to record deletion or addition. The less
active db would therefore need compaction far less often, to keep it
working at the same efficiency.

-- 
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