[Xapian-discuss] Feature request: Ligthen pressure on backup

Kevin Duraj kevin.softdev at gmail.com
Fri Mar 28 06:21:38 GMT 2008

I hate to distract community with and old issue about dropping Quartz
database in Xapian 1.0 and adopting Flint database. Several of us
posted threads that when we upgraded to Xapian 1.0 converting to Flint
database we noticed severe degradation in indexing performance.

We were told that Flint database is more compact than Quartz database
and uses less disk space and we must sacrificed some performance
because of it. It seems that this might not be entirely true, because
after some inserts and deletes from Flint database, Flint database
grows exponentially to the size of Quartz database and often must be
compact. Looks like we do not have smaller database with Flint
database than we had with Quartz database, but for sure we lost
significant performance during indexing.

Who is behind the Flint database? Can we vote on this issue as community?
Kevin Duraj

On Mon, Mar 24, 2008 at 4:19 PM, James Aylett <james-xapian at tartarus.org> wrote:
> On Mon, Mar 24, 2008 at 05:37:45PM +0100, Jesper Krogh wrote:
>  > > Note that if you ascribe external meaning to Xapian document ids (for
>  > > instance referencing them in a relational database), you may need to
>  > > change things a little (such as by bringing external ids into Xapian
>  > > and storing them in the document data, ie reversing the dependency)
>  > > because of the way multiple database support is implemented.
>  >
>  > This is excactly what I do. Can you elaborate a bit more on this?
>  >
>  > I currently do put in the database-id into the document, but it doesn't
>  > serve any purpose. I do put in an unique term into the term-set of the
>  > documents that make replace-by-term work flawlessly. Can I preserve this
>  > during a merge (that I have a "unique-term" in the documents)?
>  Unique terms aren't affected by merging documents (although you need
>  to think about how they'll work while writing the new databases). I
>  mean if you take the *Xapian* document id and store that externally,
>  you'll have problems (you just shouldn't do that in most cases).
>  J
>  --
>  /--------------------------------------------------------------------------\
>   James Aylett                                                  xapian.org
>   james at tartarus.org                               uncertaintydivision.org
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