[libreoffice-users] Re: Base Report Builder

On 01/20/2013 10:31 PM, Hank Alper wrote:

Hi Hank,

I
> restarted, LO blithely announced it was recovering my database. It did, but
> the new Report and the modifications to a query I made in this session were
> gone. I think* most* of this behavior is due to Report Builder. Has anyone
> else observed this type of behavior before ?.

My own personal advice would be not to use the autorecovery feature for
ODB files. What this feature does is save what is in the volatile memory
of the application at a given moment. This would be all well and good,
BUT, and this is the killer : an ODB file does not load all data from
the tables, reports, queries, etc into LO's volatile memory, only parts
of that data (crap design, I know, but it was done initially for
performance reasons). This means that if you get a crash, only a part of
your whole ODB file data is actually saved to a temporary file, which is
then used during the autorecovery process. The fact that you have not
lost more data/queries/reports is pure luck so far.

Instability of Base ODB files when opened within the LO application in
general is one reason (apart from dependence on Java) why there is a
search on for a replacement backend that would allow for more robust
binary streaming. In the end, it may turn out that the ODB file, as with
other db backends, e.g. server backends like mysql and postgres, will
become just a container for forms, queries and reports, and the actual
data will be held in a separate file. This should actually make the data
handling more robust, but performance might become an issue (not that
current hsqldb/ODB performance is stellar, coz it isn't). Someone was
looking at the possibility of using firebird.  For the moment, however,
nothing has been decided or actually undertaken as far as I know.

If you really need to rely on your data keeping its coherency and
consistency, my advice would be not to use the default hsqldb/ODB pair
that is provided as the default. It is a shame really, as hsqldb in
itself, certainly in its 2.0 version, is a capable db engine. It is just
the integration with AOO/LO that is one of the root causes of many of
the problems that users experience.



Alex


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