optimizing overview expiry (or: overview without expiry)

Katsuhiro Kondou Katsuhiro_Kondou at isc.org
Sat Feb 16 09:10:07 UTC 2002


In article <20020213135745.O24781 at sunbeam.de.gnumonks.org>,
	Harald Welte <laforge at gnumonks.org> wrote;

} What if the overview would contain a linked list about all crossposted
} overview entries of one article?  This is fixed-size since it just adds
} a linked list header with two pointers to every overview entry.

Where the list is located?

} I was thinking about the two options as well.  just marking it as deleted
} and then running some 'defragment' as a cronjob is one idea.

I don't think there is large difference from what
expireover does.

} Even better would be if the overview block bitmap indicated if a block is
} used or not.  Then once we write a new overview entry, we can look in the
} bitmap to find a sufficient number of 'deleted' (i.e. free) overview blocks
} and re-use them.  This way there would no 'collapsing' be needed anymore.

There is one thing to be considered.  Fragmentation of
the block.  There may be enough space in the whole block,
but the spaces are scattered and the overview data may
not be written.  How dou you try to fix without
performance degradation?
-- 
Katsuhiro Kondou


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