[Evolution-hackers] EBookBackendSqliteDB comments

[sean finney <seanius seanius net>]

Hi Everyone,

I spoke with chen on IRC this morning and got hinted at a preliminary
implementation of EBookBackendSqliteDB sitting in -ews.  Since there
are some benefits of something something like this make it's way to
a common place that could be used by -mapi as well, I thought I'd do
a quick feasability review to see what problems there might be.

Questions/commments/suggestions follow.  Please let me know what you
think!

 * No backend _get_contact/_get_contacts equivalent.  Should be
   easily implemented.
 * _add_contact/_remove_contact should be renamed to 
   _add_contacts/_remove_contacts to be consistant with other backend
   methods that take lists.
 * but also having a _add_contact/_remove_contact that takes just a uid
   (similar to other backends) would be useful
 * -mapi seems to use one cache per-profile-per-folder, but the sqlitedb
   backend takes these as calling parameters.  Not really a problem and
   I think it may be reasons to have one cache db anyway, so this is
   just more of an observation.
 * _get/_set/_delete interfaces are needed for cache metadata (last modified,
   etc).
 * if folder metadata is going to be free-form, it could be better to have
   a key->value table ( folder_id_id int, key_name text, value text ) rather
   than arbitrarily numbered text/binary fields.
 * not sure of this one: given there may be multithreaded access to the db,
   do we need to provide any external "big locks" on reads/writes?  maybe
   the built in sqlite stuff is sufficient.
 * not sure of this one: beyond the COMMIT statements, should there be
   something to periodically sync the db beyond the backend "finalize" method?  
   Unsure with commit is sufficient to get consistant on-disk in case of
   crash, etc.
 * do we need a set_populated/is_populated equivalent?  or maybe that could
   be solved in the cases it's needed wtih metadata.
 * do we need a set_time/get_time equivalent?  or maybe that could
   be solved in the cases it's needed wtih metadata.

@chen: I don't know how active you plan to be on this, but if you're looking
to offload any work, I can pick up anything that results from the above if
you like.  Just let me know!


	Sean

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