LMDB 1.0 / 0.9 database incompatibility

[Matthias Andree]

Am 04.07.26 um 21:43 schrieb Steffen Nurpmeso:
> Hello Matthias,
>
> just saw 3cee1c59bc937 -- interesting!  I have not tried LMDB 1.0
> yet, but saw some thread talking on it being entirely incompatible
> DB-wise.  Ie, 0.9 databases are simply not supported at all!
> Whereas i understand Howard Chu a bit when he says
>
>    The on-disk file format has changed in LMDB 1.0 and versions 0.9
>    and 1.0 are mutually incompatible. You must use v0.9 #mdb_dump
>    to export your old DBs, and import with v1.0 #mdb_load if you
>    want to migrate your existing data to use LMDB 1.0. There is
>    no support in LMDB 1.0 for operating directly on v0.9 DB files.
>    Including such support would only bloat the library so it will
>    not be done.
>
> it causes some trouble "downstream", and that is only the packager
> side..  A transition period would have been nice.
>
> I think i myself follow certain advices and create completely new
> packages, ie keep bogofilter-lmdb and add bogofilter-lmdb1.

For FreeBSD that would make sense for a transitional period; worst case 
we need to make a copy of the ultimate LMDB 0.9.x into bogofilter's 
sources and use it to build a feature-stripped "bogoutil" so that people 
can get a text dump of the 0.9 LMDB databases. Let's see how it plays 
out on Arch Linux and other rolling releases.

Everything tracked 
https://gitlab.com/bogofilter/bogofilter/-/work_items/21 because that's 
easiest for me. We have a quick fix for 1.0 in place, but that does not 
solve any migration pains yet, it's just "get it to work with 1.0".

For FreeBSD, see 
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=296519 and 
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=296530