What did I do wrong?

[David Relson]

On Thu, 19 Feb 2004 11:04:44 -0500 (EST)
tallison at tacocat.net wrote:

> OK, I'll be the one to ask.
> 
> Why would a dump/load, without doing anything else to the data, make
> the database smaller?

BerkeleyDB uses a sorted tree structured to keep track of data.  When an
entry is added to a full block, two blocks are needed.  This results in
partially full/empty blocks.

The dump/load sequence feeds correctly ordered tokens into an empty
database.  No block splitting needs to happen.  The result is:  same
data, less storage.  As additional tokens are added (by subsequent
bogofilter runs), blocks are split and added and storage efficiency
drops.

HTH,

David