Re: [GNUnet-developers] Replacing lookup

[Tom Barnes-Lawrence]

NB Since sending that email before, I reread the bit in the GDBM package,
I'd *thought* it said that it had become unmaintained because db2 was
better, seems it just says that glibc has libdb as the replacement dbm
system that people should be using.
I don't know if libdb and libdb2 are actually related.

On Mon, Mar 10, Christian Grothoff wrote:

> > Excuse my very ignorant question here:
> > What exactly is the reason for not using plain old berkeley DBs,
> > libdb(2/3/...)? Is it licensing issues, some missing functionality,
> > or is the performance even worse than that of gdbm?

> I have not looked into the license for there berkeley DBs.
 Looks like db2 is by a company, but licensed such that it's freely
usable to free (as in open-source) software. Plenty of packages seem
to use it and Debian distributes it.

> But like gdbm and tdb, I suspect (read: I have no clue) these are also
> "simple" Databases that are not meant for large data sets and/or high
> performance.
That *sort* of thing, but I don't know about its performance. It has
some user-programmable aspect, but I can't remember where and can't find
it in the docs now.

> it's easy to trash the database (especially whenever gnunetd segfaults)
> and gdbm can not always recover from that. Can libdb?
 I know it has "transaction support", so you can define atomic operations,
but maybe that's something you already have with gdbm.
 According to the docs, there's also a bunch of external utils, including
db_recover for this sort of event, to restore to consistency:
"all committed transactions are guaranteed to appear after db_recover
has run, and all uncommitted transactions will be completely undone."


> Running one more process has advantages. For example, we're much less likely 
> to trash the DB when we segfault that way.
 OK, that's certainly true.


> >  After all, both projects are GPL, right?
> > I expect it would be too hard tho.
> Yes, it is likely to be far too difficult to integrate anything from one DB 
> project to another -- especially since working on DBs is not really what 
> GNUnet is supposed to be about :-)
 Actually, I was thinking in terms of giving the maintainers of the
respective DB projects a friendly poke and saying "can you do this?",
but you're probably right anyway.

BTW, in light of Tracy's points about Windows users, it seems db2 is
available for them too.

Sorry if all this is wasting people's time, I know I'm no expert on this.
Tom Barnes-Lawrence