Re: State of BDB FS backend
Daniel Sahlberg <[email protected]> Fri, 24 Jul 2026 21:03:08 +0200
| Newsgroups | gmane.comp.version-control.subversion.devel |
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| Message-ID | <CAMHy98NCndO0VTJcszJqYHL3ihrLJYonmso5x4dKz8Sd6vLF1Q@mail.gmail.com> |
--000000000000d95619065760060b Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Den fre 24 juli 2026 kl 18:52 skrev Nathan Hartman <[email protected]= m >: > On Fri, Jul 24, 2026 at 11:52=E2=80=AFAM Ivan Zhakov <[email protected]> wr= ote: > > > > On Fri, 24 Jul 2026 at 15:06, Branko =C4=8Cibej <[email protected]> wrot= e: > >> > >> On 24. 7. 2026 13:57, Daniel Sahlberg wrote: > >> > >> Den fre 24 juli 2026 kl 13:30 skrev Branko =C4=8Cibej <[email protected]= g>: > >>> > >>> On 24. 7. 2026 13:23, Branko =C4=8Cibej wrote: > >>> > >>> On 24. 7. 2026 13:20, Ivan Zhakov wrote: > >>> > >>> On Sat, 18 Jul 2026 at 18:27, Nathan Hartman <[email protected]= m> > wrote: > >>> > I'm glad there's a good bit of housecleaning going on around here. > >>> > We've accumulated so much cruft over the years, it makes my > >>> > head spin. +1 to axe the ctypes bindings. > >>> > >>> Speaking of cleanups, another candidate comes to mind: the BDB FS > backend. I think now would be an appropriate time to remove it: > >>> > >>> > >>> > >>> We can't remove it before 2.0. It doesn't matter that it's deprecated= , > it's part of the published 1.0 feature set. > >>> > >>> > >>> > >>> Just to be clear: the existence of the BDB back-end is equivalent to = a > public API. We have many deprecated public APIs that we can't remove for > the same reason. > >>> > >>> -- Brane > >> > >> > > [...] > >> > >> This was discussed previously [1] and we even received a bug report > from FreeBSD that it doesn't work [2]. In the first link Yasuhito Futatsu= ki > was of the opposite opinion: the FS type is not a public API. I tend to > side with him but I could be convinced otherwise. > >> > >> As Yasuhito point out, SVN_FS_TYPE_BDB is a public API which we need t= o > keep. I didn't study details but I assume the code in libsvn_fs_base only > implement a filesystem API reachable via the fs loader (this is way over = my > paygrade so please educate me if I misunderstand something!). In that cas= e, > we won't break anyone's code so anything that compiles under 1.14 will > still compile under 1.16, but it it would not be able to load the BDB FS > backend (just as if you didn't compile it in the first place). > >> > >> Of course - we would force anyone using a BDB backend to do a > dump-and-reload cycle as part of their upgrade. > >> > >> Provided my understanding above is correct, I'm in favour of removing > BDB. > >> > >> > >> > >> What do we do with older clients that link with libsvn_fs_base when a > library upgrade makes that go away? At the very least we'd have to keep a > stub that implements all exported functions, or we break the ABI. > >> > > > > As far as I see libsvn_fs_base functions are not publicly exported. We > have some BDB FS specific functions [1] in libsvn_fs, but they already st= ub > to newer API and I agree we should keep them. > > > >> > >> In other words, even if we decide that removing BDB support isn't an > API violation, we can't do this in 1.15 because it's not a trivial change > of removing a directory and a couple lines from build.conf. > >> > > I agree and I don't think we should be doing anything about BDB in 1.15 > at this point (except for release notes). The proposed plan was about > removing it in trunk / 1.16. > > > > [1]: > https://svn.apache.org/viewvc/subversion/trunk/subversion/libsvn_fs/fs-lo= ader.c?revision=3D1936528&pathrev=3D1936528&view=3Dmarkup#l786 > > > > -- > > Ivan Zhakov > > > This was discussed several times before, such as [1], [2]. > > Arguments in favor of removing BDB: > > (1) It has been deprecated for a long time. > > (2) AFAICT most devs are no longer testing BDB so maybe it works, or > maybe it bitrotted. > > (3) Last I checked, some kind of registration was needed to get the > official sources? > > (4) It might not have many (or any) users anymore. > > Arguments against removing it: > > (1) API guarantees... > > (2) Questions about what's involved in actually ripping it out. > > (3) Users with BDB-backed repos would need to dump and load them > BEFORE we remove it... > > ...and that means we need to give very clear, advance notice. > > So this is my suggestion: For now, let's start by making the > announcement together with the 1.15.0 release. I suggest to put the > announcement in the 1.15 release notes as well as creating a separate > news item for it. In the announcement, we won't commit to removing it > by a specific date or release. We'll just convey that its removal is > being planned and may be imminent. > > After the announcement is made, Let's take as long as we need to > figure out the issues of API guarantees, how/what to remove, etc. > There's no rush to do the actual removal, but I think the announcement > needs to give users as much time as possible. > > Proposed initial draft of announcement: > > [[[ > > IMPORTANT NOTICE: Subversion's Berkeley DB repository backend (BDB) > has been deprecated since Subversion 1.8 (13 years) and is planned for > REMOVAL with a future Subversion release line. It will not be possible > to access BDB-backed Subversion repositories after upgrading to a > Subversion release that no longer supports it. The Subversion 1.15.x > release line may be the last minor release line to support the BDB > backend. > > Users who have BDB-backed Subversion repositories should upgrade them > to the newer FSFS backend as soon as possible to avoid disruption. > FSFS has been the default since Subversion 1.2 (21 years). This > requires to "dump" the repository using a Subversion release that > supports BDB and then to "load" the repository using any recent > Subversion release. For details, please see the FAQ entry "How do I > convert my repository from using BDB to FSFS or from FSFS to BDB?": > https://subversion.apache.org/faq.html#bdb-fsfs-convert > > ]]] > > Commenting on my own initial draft: > > Instead of sending them to the FAQ, maybe we'd want to write clear > backup/dump/load instructions directly in the announcement? > > Do we want to point out that the BDB backend might not be as well > tested as FSFS these days? > > WDYT? > I think this is a good plan. I would prefer to keep the announcement as short as possible and link to the FAQ, improving that if needed. I seem to remember that we at one point has talked about the lack of testing - but that may just be on the mailing list..? I would probably not mention it in the announcement - either something is supported or it is NOT supported. Cheers, Daniel > > [1] "Berkely DB precompiled for Windows" > Posted to dev@ on 26 Sept 2024 > https://lists.apache.org/thread/m4o5l9rntc98y6s8wrhsn329by9bhr19 > Continued here (disconnected in the archives): > https://lists.apache.org/thread/99zo1wq003109p06dt1tcxyzd7cyyw32 > and here: > https://lists.apache.org/thread/7plrvmhk3c0jvhkq1tfwds8j4tmlgslc > > [2] "Removing BDB support from 1.15" > Posted to dev@ on 18 Mar 2025 > https://lists.apache.org/thread/kn0yw4f8p6tn2tzq4obr5r5v609g6g1m > > Cheers, > Nathan > --000000000000d95619065760060b Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable <div dir=3D"ltr"><div dir=3D"ltr"><span style=3D"background-color:transpare= nt">Den fre 24 juli 2026 kl 18:52 skrev Nathan Hartman <<a href=3D"mailt= o:[email protected]">[email protected]</a>>:</span></div><= div class=3D"gmail_quote gmail_quote_container"><blockquote class=3D"gmail_= quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,= 204);padding-left:1ex">On Fri, Jul 24, 2026 at 11:52=E2=80=AFAM Ivan Zhakov= <<a href=3D"mailto:[email protected]" target=3D"_blank">[email protected]</= a>> wrote:<br> ><br> > On Fri, 24 Jul 2026 at 15:06, Branko =C4=8Cibej <<a href=3D"mailto:= [email protected]" target=3D"_blank">[email protected]</a>> wrote:<br> >><br> >> On 24. 7. 2026 13:57, Daniel Sahlberg wrote:<br> >><br> >> Den fre 24 juli 2026 kl 13:30 skrev Branko =C4=8Cibej <<a href= =3D"mailto:[email protected]" target=3D"_blank">[email protected]</a>>:<br= > >>><br> >>> On 24. 7. 2026 13:23, Branko =C4=8Cibej wrote:<br> >>><br> >>> On 24. 7. 2026 13:20, Ivan Zhakov wrote:<br> >>><br> >>> On Sat, 18 Jul 2026 at 18:27, Nathan Hartman <<a href=3D"ma= ilto:[email protected]" target=3D"_blank">[email protected]</= a>> wrote:<br> >>> > I'm glad there's a good bit of housecleaning goin= g on around here.<br> >>> > We've accumulated so much cruft over the years, it ma= kes my<br> >>> > head spin. +1 to axe the ctypes bindings.<br> >>><br> >>> Speaking of cleanups, another candidate comes to mind: the BDB= FS backend. I think now would be an appropriate time to remove it:<br> >>><br> >>><br> >>><br> >>> We can't remove it before 2.0. It doesn't matter that = it's deprecated, it's part of the published 1.0 feature set.<br> >>><br> >>><br> >>><br> >>> Just to be clear: the existence of the BDB back-end is equival= ent to a public API. We have many deprecated public APIs that we can't = remove for the same reason.<br> >>><br> >>> -- Brane<br> >><br> >><br> > [...]<br> >><br> >> This was discussed previously [1] and we even received a bug repor= t from FreeBSD that it doesn't work [2]. In the first link Yasuhito Fut= atsuki was of the opposite opinion: the FS type is not a public API. I tend= to side with him but I could be convinced otherwise.<br> >><br> >> As Yasuhito point out, SVN_FS_TYPE_BDB is a public API which we ne= ed to keep. I didn't study details but I assume the code in libsvn_fs_b= ase only implement a filesystem API reachable via the fs loader (this is wa= y over my paygrade so please educate me if I misunderstand something!). In = that case, we won't break anyone's code so anything that compiles u= nder 1.14 will still compile under 1.16, but it it would not be able to loa= d the BDB FS backend (just as if you didn't compile it in the first pla= ce).<br> >><br> >> Of course - we would force anyone using a BDB backend to do a dump= -and-reload cycle as part of their upgrade.<br> >><br> >> Provided my understanding above is correct, I'm in favour of r= emoving BDB.<br> >><br> >><br> >><br> >> What do we do with older clients that link with libsvn_fs_base whe= n a library upgrade makes that go away? At the very least we'd have to = keep a stub that implements all exported functions, or we break the ABI.<br= > >><br> ><br> > As far as I see libsvn_fs_base functions are not publicly exported. We= have some BDB FS specific functions [1] in libsvn_fs, but they already stu= b to newer API and I agree we should keep them.<br> ><br> >><br> >> In other words, even if we decide that removing BDB support isn= 9;t an API violation, we can't do this in 1.15 because it's not a t= rivial change of removing a directory and a couple lines from build.conf.<b= r> >><br> > I agree and I don't think we should be doing anything about BDB in= 1.15 at this point (except for release notes). The proposed plan was about= removing it in trunk / 1.16.<br> ><br> > [1]: <a href=3D"https://svn.apache.org/viewvc/subversion/trunk/subvers= ion/libsvn_fs/fs-loader.c?revision=3D1936528&pathrev=3D1936528&view= =3Dmarkup#l786" rel=3D"noreferrer" target=3D"_blank">https://svn.apache.org= /viewvc/subversion/trunk/subversion/libsvn_fs/fs-loader.c?revision=3D193652= 8&pathrev=3D1936528&view=3Dmarkup#l786</a><br> ><br> > --<br> > Ivan Zhakov<br> <br> <br> This was discussed several times before, such as [1], [2].<br> <br> Arguments in favor of removing BDB:<br> <br> (1) It has been deprecated for a long time.<br> <br> (2) AFAICT most devs are no longer testing BDB so maybe it works, or<br> maybe it bitrotted.<br> <br> (3) Last I checked, some kind of registration was needed to get the<br> official sources?<br> <br> (4) It might not have many (or any) users anymore.<br> <br> Arguments against removing it:<br> <br> (1) API guarantees...<br> <br> (2) Questions about what's involved in actually ripping it out.<br> <br> (3) Users with BDB-backed repos would need to dump and load them<br> BEFORE we remove it...<br> <br> ...and that means we need to give very clear, advance notice.<br> <br> So this is my suggestion: For now, let's start by making the<br> announcement together with the 1.15.0 release. I suggest to put the<br> announcement in the 1.15 release notes as well as creating a separate<br> news item for it. In the announcement, we won't commit to removing it<b= r> by a specific date or release. We'll just convey that its removal is<br= > being planned and may be imminent.<br> <br> After the announcement is made, Let's take as long as we need to<br> figure out the issues of API guarantees, how/what to remove, etc.<br> There's no rush to do the actual removal, but I think the announcement<= br> needs to give users as much time as possible.<br> <br> Proposed initial draft of announcement:<br> <br> [[[<br> <br> IMPORTANT NOTICE: Subversion's Berkeley DB repository backend (BDB)<br> has been deprecated since Subversion 1.8 (13 years) and is planned for<br> REMOVAL with a future Subversion release line. It will not be possible<br> to access BDB-backed Subversion repositories after upgrading to a<br> Subversion release that no longer supports it. The Subversion 1.15.x<br> release line may be the last minor release line to support the BDB<br> backend.<br> <br> Users who have BDB-backed Subversion repositories should upgrade them<br> to the newer FSFS backend as soon as possible to avoid disruption.<br> FSFS has been the default since Subversion 1.2 (21 years). This<br> requires to "dump" the repository using a Subversion release that= <br> supports BDB and then to "load" the repository using any recent<b= r> Subversion release. For details, please see the FAQ entry "How do I<br= > convert my repository from using BDB to FSFS or from FSFS to BDB?":<br= > <a href=3D"https://subversion.apache.org/faq.html#bdb-fsfs-convert" rel=3D"= noreferrer" target=3D"_blank">https://subversion.apache.org/faq.html#bdb-fs= fs-convert</a><br> <br> ]]]<br> <br> Commenting on my own initial draft:<br> <br> Instead of sending them to the FAQ, maybe we'd want to write clear<br> backup/dump/load instructions directly in the announcement?<br> <br> Do we want to point out that the BDB backend might not be as well<br> tested as FSFS these days?<br> <br> WDYT?<br></blockquote><div><br></div><div>I think this is a good plan. I wo= uld prefer to keep the announcement as short as possible and link to the FA= Q, improving that if needed.</div><div><br></div><div>I seem to remember th= at we at one point has talked about the lack of testing - but that may just= be on the mailing list..? I would probably not mention it in the announcem= ent - either something is supported or it is NOT supported.</div><div><br><= /div><div>Cheers,</div><div>Daniel</div><div><br></div><div>=C2=A0</div><bl= ockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-lef= t:1px solid rgb(204,204,204);padding-left:1ex"> <br> [1] "Berkely DB precompiled for Windows"<br> =C2=A0 =C2=A0 Posted to dev@ on 26 Sept 2024<br> =C2=A0 =C2=A0 =C2=A0 <a href=3D"https://lists.apache.org/thread/m4o5l9rntc9= 8y6s8wrhsn329by9bhr19" rel=3D"noreferrer" target=3D"_blank">https://lists.a= pache.org/thread/m4o5l9rntc98y6s8wrhsn329by9bhr19</a><br> =C2=A0 =C2=A0 Continued here (disconnected in the archives):<br> =C2=A0 =C2=A0 =C2=A0 <a href=3D"https://lists.apache.org/thread/99zo1wq0031= 09p06dt1tcxyzd7cyyw32" rel=3D"noreferrer" target=3D"_blank">https://lists.a= pache.org/thread/99zo1wq003109p06dt1tcxyzd7cyyw32</a><br> =C2=A0 =C2=A0 and here:<br> =C2=A0 =C2=A0 =C2=A0 <a href=3D"https://lists.apache.org/thread/7plrvmhk3c0= jvhkq1tfwds8j4tmlgslc" rel=3D"noreferrer" target=3D"_blank">https://lists.a= pache.org/thread/7plrvmhk3c0jvhkq1tfwds8j4tmlgslc</a><br> <br> [2] "Removing BDB support from 1.15"<br> =C2=A0 =C2=A0 Posted to dev@ on 18 Mar 2025<br> =C2=A0 =C2=A0 =C2=A0 <a href=3D"https://lists.apache.org/thread/kn0yw4f8p6t= n2tzq4obr5r5v609g6g1m" rel=3D"noreferrer" target=3D"_blank">https://lists.a= pache.org/thread/kn0yw4f8p6tn2tzq4obr5r5v609g6g1m</a><br> <br> Cheers,<br> Nathan<br> </blockquote></div></div> --000000000000d95619065760060b--