LMDB 1.0 / 0.9 database incompatibility

[Steffen Nurpmeso]

Hello Matthias.

Matthias Andree via bogofilter-dev wrote in
 <d19429bc-83a0-4c32-8fa5-c6a88c0a9cec at gmx.de>:
 |Am 04.07.26 um 21:43 schrieb Steffen Nurpmeso:
 |> 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

Maybe the lmdb0 way of doing things is even better, i will do
this, too.
But this mdb_env_get_maxkeysize() thing you fixed and say
"bogofilter bug" to in work_items/21 is a LMDB upstream bug:
either they should fix their documentation, which still says
_create() is what is expected, not _open(), or they need to fix
their code.
Do you talk with LMDB upstream already?

Ciao,

--steffen
|
|Der Kragenbaer,                The moon bear,
|der holt sich munter           he cheerfully and one by one
|einen nach dem anderen runter  wa.ks himself off
|(By Robert Gernhardt)