20 Feb
2014
20 Feb
'14
11:52 p.m.
Alexey Shamrin wrote:
Is it really needed in this particular case? OpenBSC would continue
working with SQLite < 3.7.0. It would just ignore `journal_mode = WAL`
and keep using `DELETE` mode. The only thing that won't work is
downgrading from newer SQLite to older while keeping the same database
file. Older SQLite would refuse to open the database that was once
opened in WAL mode. The file could be downgraded by changing
journal_mode on it. But only newer SQLite could do it. Do you think
something must be done about it?
Thanks for explaining in more detail! I do think something more needs
to be done but I'm no longer so sure what I'd prefer..
I think it would be good to have a build-time (configure) option to
explicitly enable WAL journalling and thus also require the newer
SQLite version.
I also think that a version of OpenBSC built without WAL enabled
has to be able to recognize databases created by OpenBSC built *with*
WAL enabled, and tell the user what needs to be done to make the
database work.
Finally, maybe the database version number should also be bumped, to
allow OpenBSC using >=3.7 to know whether a database needs WAL or not.
As far as I understand, Ivan noticed the problem, opened the database
with sqlite3 command, entered `PRAGMA journal_mode = WAL` and noticed
the problem was now gone. Then he told me about it and suggested to
write a patch. I found where to put this command in OpenBSC source,
tested that it indeed persists WAL mode in the file, wrote the commit
message and sent it to mailing list.
Oh ok, yes, then I think you should be the author and actually some
more of the above explanation could easily be in the commit message. :)
//Peter
WAL journaling mode is persistent; it stays in effect
after closing and
reopening the database. WAL mode database requires SQLite >= 3.7.0.
Think about
this some more. It's not enough to state dependencies in
a commit message, you need to put them in the build system. A patch
to do this will need to touch configure.ac, and I think it would be
wise to make the requirement optional. All credit belongs Ivan Kluchnikov who diagnosed and
fixed this issue.
Then the commit should list him as author, right?