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Posted to users@subversion.apache.org by Vyacheslav Zholudev <vy...@gmail.com> on 2011/11/25 01:08:07 UTC
BDB backend in SVN 1.7.1
Hi,
how does SVN 1.7.1 store fulltext and deltas in the BDB backend? From some time ago I remember that previous versions of SVN stored "almost" always a HEAD revision as fulltext, and others as reverse deltas.(except the case when a delta is bigger that fulltext) Was this behavior changed in SVN 1.7? I've looked at the notes about BDB and they don't differ almost at all from SVN 1.4's ones. Of course, I could look into the code more carefully, but my hope was that it wouldn't be a big deal to give me a short answer, if possible.
Thanks in advance!
Best,
Vyacheslav
Re: BDB backend in SVN 1.7.1
Posted by Vyacheslav Zholudev <vy...@gmail.com>.
On Nov 25, 2011, at 2:02 PM, Stefan Sperling wrote:
> On Fri, Nov 25, 2011 at 01:38:44PM +0100, Vyacheslav Zholudev wrote:
>> I guess "badness" can happen only when accessing repositories locally (not via svn:// or http(s)://) with patched and not patched SVN.
>> But usually only one version of SVN is installed on the server side, so that should not be a big problem.
>>
>> However, it's a nice exercise to check.
>
> Out of curiosity, what is the reason for this entire exercise?
> Is it purely academic or is there a use case where storing the HEAD
> revision as full-text is critical?
The reason for this is that I had a project based on SVN 1.4 which stored HEAD revisions of XML files in Berkeley DB XML - a native XML database-, instead of BDB. (reverted deltas as well as "normal" files kept on living in BDB). In this way I could also query HEAD XML files directly from SVN repository and access them via BDB XML API - thus it was a nice combination of SVN and XML-database. Recently I've ported my project to SVN 1.7 and due to forward deltas it didn't work as before -- only old revisions of XML files were in BDB XML. But now I changed SVN_FS_BASE__MIN_FORWARD_DELTAS_FORMAT to a higher number, and my project works again as expected.
Vyacheslav
Re: BDB backend in SVN 1.7.1
Posted by Stefan Sperling <st...@elego.de>.
On Fri, Nov 25, 2011 at 01:38:44PM +0100, Vyacheslav Zholudev wrote:
> I guess "badness" can happen only when accessing repositories locally (not via svn:// or http(s)://) with patched and not patched SVN.
> But usually only one version of SVN is installed on the server side, so that should not be a big problem.
>
> However, it's a nice exercise to check.
Out of curiosity, what is the reason for this entire exercise?
Is it purely academic or is there a use case where storing the HEAD
revision as full-text is critical?
Re: BDB backend in SVN 1.7.1
Posted by Vyacheslav Zholudev <vy...@gmail.com>.
I guess "badness" can happen only when accessing repositories locally (not via svn:// or http(s)://) with patched and not patched SVN.
But usually only one version of SVN is installed on the server side, so that should not be a big problem.
However, it's a nice exercise to check.
Vyacheslav
On Nov 25, 2011, at 1:29 PM, Daniel Shahaf wrote:
> To clarify, the issues I was concerned about weren't with tree changes
> (the level of the code dealing with content reps isn't aware of those),
> but with creating/accessing a single repository sometimes via
> unmodified svn 1.7.1 libraries and sometimes via forward-delta-patched
> libraries.
>
> The part I left to the readers was determining whther or not Badness
> will happen in the event of such "mixed" access.
>
> Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 13:20:55 +0100:
>> Thanks, I studied math not in English, that's why I didn't know :)
>>
>> I made a simple tests and it seems to work nicely. However, I'm not sure whether it will work with more complicated cases like copying, deleting, etc.
>>
>>
>> Vyacheslav
>>
>> On Nov 25, 2011, at 1:15 PM, Daniel Shahaf wrote:
>>
>>> "left as an exercise for the reader" --- in other words, I was
>>> identifying a potential issue and letting the audience figure out the
>>> solution for themselves. It's a standard idiom in math textbooks...
>>>
>>> (and, of course, if you have questions about that interoperability
>>> issue, feel free to raise them on this list.)
>>>
>>> Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 13:07:52 +0100:
>>>> Thanks, Daniel. That's the pointer I needed.
>>>> However, I didn't understand what LAAEFTR means.
>>>>
>>>> Vyacheslav
>>>>
>>>>
>>>> On Nov 25, 2011, at 12:17 PM, Daniel Shahaf wrote:
>>>>
>>>>> Change SVN_FS_BASE__MIN_FORWARD_DELTAS_FORMAT to be larger than
>>>>> SVN_FS_BASE__FORMAT_NUMBER.
>>>>>
>>>>> Whether repositories created by an svn patched in this way will be
>>>>> interoperable with repositories created by an unpatched svn is
>>>>> LAAEFTR'd. I'd be cautious and change db/fs-type or db/format.
>>>>>
>>>>> Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 12:04:22 +0100:
>>>>>> Hi Daniel,
>>>>>>
>>>>>> would it be easy to change the code (I want to do it for my experiments) so that the HEAD (youngest) revisions are stored as fulltexts? Or is it something that was not foreseen by design to easily switch between approaches of representing history information?
>>>>>>
>>>>>> Thanks,
>>>>>> Vyacheslav
>>>>>>
>>>>>> On Nov 25, 2011, at 11:59 AM, Daniel Shahaf wrote:
>>>>>>
>>>>>>> Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 11:13:00 +0100:
>>>>>>>>
>>>>>>>>> Old BDB-backed repositories stored the older revision as fulltext and
>>>>>>>>> newer revisions as deltas.
>>>>>>>>
>>>>>>>> Really?
>>>>>>>
>>>>>>> It seems that I should have swapped "older" and "newer" in the quoted
>>>>>>> sentence. Thanks for catching that.
>>>>>>>
>>>>>>>> Here is a quotation from SVN 1.4.6 libsvn_fs_base/note/structure:
>>>>>>>> "At present, Subversion generally stores
>>>>>>>> the youngest strings in "fulltext" form, and older strings as "delta"s
>>>>>>>> against them (unless the delta would save no space compared to the
>>>>>>>> fulltext).
>>>>>>>> "
>>>>>>>> My own experiments with SVN 1.4 code confirm that.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>> Repositories created with or 'svnadmin
>>>>>>>>> upgrade'd by 1.6 and newer reverse this for new revisions of files
>>>>>>>>> (while making sure not to introduce a dependency loop in the direction
>>>>>>>>> of deltas).
>>>>>>>>>
>>>>>>>>> http://subversion.apache.org/docs/release-notes/1.6#bdb-forward-deltas
>>>>>>>>>
>>>>>>>>> On Friday, November 25, 2011 1:08 AM, "Vyacheslav Zholudev" <vy...@gmail.com> wrote:
>>>>>>>>>> Hi,
>>>>>>>>>>
>>>>>>>>>> how does SVN 1.7.1 store fulltext and deltas in the BDB backend? From some time ago I remember that previous versions of SVN stored "almost" always a HEAD revision as fulltext, and others as reverse deltas.(except the case when a delta is bigger that fulltext) Was this behavior changed in SVN 1.7? I've looked at the notes about BDB and they don't differ almost at all from SVN 1.4's ones. Of course, I could look into the code more carefully, but my hope was that it wouldn't be a big deal to give me a short answer, if possible.
>>>>>>>>>>
>>>>>>>>>> Thanks in advance!
>>>>>>>>>>
>>>>>>>>>> Best,
>>>>>>>>>> Vyacheslav
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>
>>>>>>
>>>>
>>
Re: BDB backend in SVN 1.7.1
Posted by Daniel Shahaf <d....@daniel.shahaf.name>.
To clarify, the issues I was concerned about weren't with tree changes
(the level of the code dealing with content reps isn't aware of those),
but with creating/accessing a single repository sometimes via
unmodified svn 1.7.1 libraries and sometimes via forward-delta-patched
libraries.
The part I left to the readers was determining whther or not Badness
will happen in the event of such "mixed" access.
Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 13:20:55 +0100:
> Thanks, I studied math not in English, that's why I didn't know :)
>
> I made a simple tests and it seems to work nicely. However, I'm not sure whether it will work with more complicated cases like copying, deleting, etc.
>
>
> Vyacheslav
>
> On Nov 25, 2011, at 1:15 PM, Daniel Shahaf wrote:
>
> > "left as an exercise for the reader" --- in other words, I was
> > identifying a potential issue and letting the audience figure out the
> > solution for themselves. It's a standard idiom in math textbooks...
> >
> > (and, of course, if you have questions about that interoperability
> > issue, feel free to raise them on this list.)
> >
> > Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 13:07:52 +0100:
> >> Thanks, Daniel. That's the pointer I needed.
> >> However, I didn't understand what LAAEFTR means.
> >>
> >> Vyacheslav
> >>
> >>
> >> On Nov 25, 2011, at 12:17 PM, Daniel Shahaf wrote:
> >>
> >>> Change SVN_FS_BASE__MIN_FORWARD_DELTAS_FORMAT to be larger than
> >>> SVN_FS_BASE__FORMAT_NUMBER.
> >>>
> >>> Whether repositories created by an svn patched in this way will be
> >>> interoperable with repositories created by an unpatched svn is
> >>> LAAEFTR'd. I'd be cautious and change db/fs-type or db/format.
> >>>
> >>> Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 12:04:22 +0100:
> >>>> Hi Daniel,
> >>>>
> >>>> would it be easy to change the code (I want to do it for my experiments) so that the HEAD (youngest) revisions are stored as fulltexts? Or is it something that was not foreseen by design to easily switch between approaches of representing history information?
> >>>>
> >>>> Thanks,
> >>>> Vyacheslav
> >>>>
> >>>> On Nov 25, 2011, at 11:59 AM, Daniel Shahaf wrote:
> >>>>
> >>>>> Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 11:13:00 +0100:
> >>>>>>
> >>>>>>> Old BDB-backed repositories stored the older revision as fulltext and
> >>>>>>> newer revisions as deltas.
> >>>>>>
> >>>>>> Really?
> >>>>>
> >>>>> It seems that I should have swapped "older" and "newer" in the quoted
> >>>>> sentence. Thanks for catching that.
> >>>>>
> >>>>>> Here is a quotation from SVN 1.4.6 libsvn_fs_base/note/structure:
> >>>>>> "At present, Subversion generally stores
> >>>>>> the youngest strings in "fulltext" form, and older strings as "delta"s
> >>>>>> against them (unless the delta would save no space compared to the
> >>>>>> fulltext).
> >>>>>> "
> >>>>>> My own experiments with SVN 1.4 code confirm that.
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>> Repositories created with or 'svnadmin
> >>>>>>> upgrade'd by 1.6 and newer reverse this for new revisions of files
> >>>>>>> (while making sure not to introduce a dependency loop in the direction
> >>>>>>> of deltas).
> >>>>>>>
> >>>>>>> http://subversion.apache.org/docs/release-notes/1.6#bdb-forward-deltas
> >>>>>>>
> >>>>>>> On Friday, November 25, 2011 1:08 AM, "Vyacheslav Zholudev" <vy...@gmail.com> wrote:
> >>>>>>>> Hi,
> >>>>>>>>
> >>>>>>>> how does SVN 1.7.1 store fulltext and deltas in the BDB backend? From some time ago I remember that previous versions of SVN stored "almost" always a HEAD revision as fulltext, and others as reverse deltas.(except the case when a delta is bigger that fulltext) Was this behavior changed in SVN 1.7? I've looked at the notes about BDB and they don't differ almost at all from SVN 1.4's ones. Of course, I could look into the code more carefully, but my hope was that it wouldn't be a big deal to give me a short answer, if possible.
> >>>>>>>>
> >>>>>>>> Thanks in advance!
> >>>>>>>>
> >>>>>>>> Best,
> >>>>>>>> Vyacheslav
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>
> >>>>
> >>
>
Re: BDB backend in SVN 1.7.1
Posted by Vyacheslav Zholudev <vy...@gmail.com>.
Thanks, I studied math not in English, that's why I didn't know :)
I made a simple tests and it seems to work nicely. However, I'm not sure whether it will work with more complicated cases like copying, deleting, etc.
Vyacheslav
On Nov 25, 2011, at 1:15 PM, Daniel Shahaf wrote:
> "left as an exercise for the reader" --- in other words, I was
> identifying a potential issue and letting the audience figure out the
> solution for themselves. It's a standard idiom in math textbooks...
>
> (and, of course, if you have questions about that interoperability
> issue, feel free to raise them on this list.)
>
> Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 13:07:52 +0100:
>> Thanks, Daniel. That's the pointer I needed.
>> However, I didn't understand what LAAEFTR means.
>>
>> Vyacheslav
>>
>>
>> On Nov 25, 2011, at 12:17 PM, Daniel Shahaf wrote:
>>
>>> Change SVN_FS_BASE__MIN_FORWARD_DELTAS_FORMAT to be larger than
>>> SVN_FS_BASE__FORMAT_NUMBER.
>>>
>>> Whether repositories created by an svn patched in this way will be
>>> interoperable with repositories created by an unpatched svn is
>>> LAAEFTR'd. I'd be cautious and change db/fs-type or db/format.
>>>
>>> Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 12:04:22 +0100:
>>>> Hi Daniel,
>>>>
>>>> would it be easy to change the code (I want to do it for my experiments) so that the HEAD (youngest) revisions are stored as fulltexts? Or is it something that was not foreseen by design to easily switch between approaches of representing history information?
>>>>
>>>> Thanks,
>>>> Vyacheslav
>>>>
>>>> On Nov 25, 2011, at 11:59 AM, Daniel Shahaf wrote:
>>>>
>>>>> Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 11:13:00 +0100:
>>>>>>
>>>>>>> Old BDB-backed repositories stored the older revision as fulltext and
>>>>>>> newer revisions as deltas.
>>>>>>
>>>>>> Really?
>>>>>
>>>>> It seems that I should have swapped "older" and "newer" in the quoted
>>>>> sentence. Thanks for catching that.
>>>>>
>>>>>> Here is a quotation from SVN 1.4.6 libsvn_fs_base/note/structure:
>>>>>> "At present, Subversion generally stores
>>>>>> the youngest strings in "fulltext" form, and older strings as "delta"s
>>>>>> against them (unless the delta would save no space compared to the
>>>>>> fulltext).
>>>>>> "
>>>>>> My own experiments with SVN 1.4 code confirm that.
>>>>>>
>>>>>>
>>>>>>
>>>>>>> Repositories created with or 'svnadmin
>>>>>>> upgrade'd by 1.6 and newer reverse this for new revisions of files
>>>>>>> (while making sure not to introduce a dependency loop in the direction
>>>>>>> of deltas).
>>>>>>>
>>>>>>> http://subversion.apache.org/docs/release-notes/1.6#bdb-forward-deltas
>>>>>>>
>>>>>>> On Friday, November 25, 2011 1:08 AM, "Vyacheslav Zholudev" <vy...@gmail.com> wrote:
>>>>>>>> Hi,
>>>>>>>>
>>>>>>>> how does SVN 1.7.1 store fulltext and deltas in the BDB backend? From some time ago I remember that previous versions of SVN stored "almost" always a HEAD revision as fulltext, and others as reverse deltas.(except the case when a delta is bigger that fulltext) Was this behavior changed in SVN 1.7? I've looked at the notes about BDB and they don't differ almost at all from SVN 1.4's ones. Of course, I could look into the code more carefully, but my hope was that it wouldn't be a big deal to give me a short answer, if possible.
>>>>>>>>
>>>>>>>> Thanks in advance!
>>>>>>>>
>>>>>>>> Best,
>>>>>>>> Vyacheslav
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>
>>>>
>>
Re: BDB backend in SVN 1.7.1
Posted by Daniel Shahaf <d....@daniel.shahaf.name>.
"left as an exercise for the reader" --- in other words, I was
identifying a potential issue and letting the audience figure out the
solution for themselves. It's a standard idiom in math textbooks...
(and, of course, if you have questions about that interoperability
issue, feel free to raise them on this list.)
Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 13:07:52 +0100:
> Thanks, Daniel. That's the pointer I needed.
> However, I didn't understand what LAAEFTR means.
>
> Vyacheslav
>
>
> On Nov 25, 2011, at 12:17 PM, Daniel Shahaf wrote:
>
> > Change SVN_FS_BASE__MIN_FORWARD_DELTAS_FORMAT to be larger than
> > SVN_FS_BASE__FORMAT_NUMBER.
> >
> > Whether repositories created by an svn patched in this way will be
> > interoperable with repositories created by an unpatched svn is
> > LAAEFTR'd. I'd be cautious and change db/fs-type or db/format.
> >
> > Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 12:04:22 +0100:
> >> Hi Daniel,
> >>
> >> would it be easy to change the code (I want to do it for my experiments) so that the HEAD (youngest) revisions are stored as fulltexts? Or is it something that was not foreseen by design to easily switch between approaches of representing history information?
> >>
> >> Thanks,
> >> Vyacheslav
> >>
> >> On Nov 25, 2011, at 11:59 AM, Daniel Shahaf wrote:
> >>
> >>> Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 11:13:00 +0100:
> >>>>
> >>>>> Old BDB-backed repositories stored the older revision as fulltext and
> >>>>> newer revisions as deltas.
> >>>>
> >>>> Really?
> >>>
> >>> It seems that I should have swapped "older" and "newer" in the quoted
> >>> sentence. Thanks for catching that.
> >>>
> >>>> Here is a quotation from SVN 1.4.6 libsvn_fs_base/note/structure:
> >>>> "At present, Subversion generally stores
> >>>> the youngest strings in "fulltext" form, and older strings as "delta"s
> >>>> against them (unless the delta would save no space compared to the
> >>>> fulltext).
> >>>> "
> >>>> My own experiments with SVN 1.4 code confirm that.
> >>>>
> >>>>
> >>>>
> >>>>> Repositories created with or 'svnadmin
> >>>>> upgrade'd by 1.6 and newer reverse this for new revisions of files
> >>>>> (while making sure not to introduce a dependency loop in the direction
> >>>>> of deltas).
> >>>>>
> >>>>> http://subversion.apache.org/docs/release-notes/1.6#bdb-forward-deltas
> >>>>>
> >>>>> On Friday, November 25, 2011 1:08 AM, "Vyacheslav Zholudev" <vy...@gmail.com> wrote:
> >>>>>> Hi,
> >>>>>>
> >>>>>> how does SVN 1.7.1 store fulltext and deltas in the BDB backend? From some time ago I remember that previous versions of SVN stored "almost" always a HEAD revision as fulltext, and others as reverse deltas.(except the case when a delta is bigger that fulltext) Was this behavior changed in SVN 1.7? I've looked at the notes about BDB and they don't differ almost at all from SVN 1.4's ones. Of course, I could look into the code more carefully, but my hope was that it wouldn't be a big deal to give me a short answer, if possible.
> >>>>>>
> >>>>>> Thanks in advance!
> >>>>>>
> >>>>>> Best,
> >>>>>> Vyacheslav
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>
> >>
>
Re: BDB backend in SVN 1.7.1
Posted by Vyacheslav Zholudev <vy...@gmail.com>.
Thanks, Daniel. That's the pointer I needed.
However, I didn't understand what LAAEFTR means.
Vyacheslav
On Nov 25, 2011, at 12:17 PM, Daniel Shahaf wrote:
> Change SVN_FS_BASE__MIN_FORWARD_DELTAS_FORMAT to be larger than
> SVN_FS_BASE__FORMAT_NUMBER.
>
> Whether repositories created by an svn patched in this way will be
> interoperable with repositories created by an unpatched svn is
> LAAEFTR'd. I'd be cautious and change db/fs-type or db/format.
>
> Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 12:04:22 +0100:
>> Hi Daniel,
>>
>> would it be easy to change the code (I want to do it for my experiments) so that the HEAD (youngest) revisions are stored as fulltexts? Or is it something that was not foreseen by design to easily switch between approaches of representing history information?
>>
>> Thanks,
>> Vyacheslav
>>
>> On Nov 25, 2011, at 11:59 AM, Daniel Shahaf wrote:
>>
>>> Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 11:13:00 +0100:
>>>>
>>>>> Old BDB-backed repositories stored the older revision as fulltext and
>>>>> newer revisions as deltas.
>>>>
>>>> Really?
>>>
>>> It seems that I should have swapped "older" and "newer" in the quoted
>>> sentence. Thanks for catching that.
>>>
>>>> Here is a quotation from SVN 1.4.6 libsvn_fs_base/note/structure:
>>>> "At present, Subversion generally stores
>>>> the youngest strings in "fulltext" form, and older strings as "delta"s
>>>> against them (unless the delta would save no space compared to the
>>>> fulltext).
>>>> "
>>>> My own experiments with SVN 1.4 code confirm that.
>>>>
>>>>
>>>>
>>>>> Repositories created with or 'svnadmin
>>>>> upgrade'd by 1.6 and newer reverse this for new revisions of files
>>>>> (while making sure not to introduce a dependency loop in the direction
>>>>> of deltas).
>>>>>
>>>>> http://subversion.apache.org/docs/release-notes/1.6#bdb-forward-deltas
>>>>>
>>>>> On Friday, November 25, 2011 1:08 AM, "Vyacheslav Zholudev" <vy...@gmail.com> wrote:
>>>>>> Hi,
>>>>>>
>>>>>> how does SVN 1.7.1 store fulltext and deltas in the BDB backend? From some time ago I remember that previous versions of SVN stored "almost" always a HEAD revision as fulltext, and others as reverse deltas.(except the case when a delta is bigger that fulltext) Was this behavior changed in SVN 1.7? I've looked at the notes about BDB and they don't differ almost at all from SVN 1.4's ones. Of course, I could look into the code more carefully, but my hope was that it wouldn't be a big deal to give me a short answer, if possible.
>>>>>>
>>>>>> Thanks in advance!
>>>>>>
>>>>>> Best,
>>>>>> Vyacheslav
>>>>>>
>>>>>>
>>>>>>
>>>>
>>
Re: BDB backend in SVN 1.7.1
Posted by Daniel Shahaf <d....@daniel.shahaf.name>.
Change SVN_FS_BASE__MIN_FORWARD_DELTAS_FORMAT to be larger than
SVN_FS_BASE__FORMAT_NUMBER.
Whether repositories created by an svn patched in this way will be
interoperable with repositories created by an unpatched svn is
LAAEFTR'd. I'd be cautious and change db/fs-type or db/format.
Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 12:04:22 +0100:
> Hi Daniel,
>
> would it be easy to change the code (I want to do it for my experiments) so that the HEAD (youngest) revisions are stored as fulltexts? Or is it something that was not foreseen by design to easily switch between approaches of representing history information?
>
> Thanks,
> Vyacheslav
>
> On Nov 25, 2011, at 11:59 AM, Daniel Shahaf wrote:
>
> > Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 11:13:00 +0100:
> >>
> >>> Old BDB-backed repositories stored the older revision as fulltext and
> >>> newer revisions as deltas.
> >>
> >> Really?
> >
> > It seems that I should have swapped "older" and "newer" in the quoted
> > sentence. Thanks for catching that.
> >
> >> Here is a quotation from SVN 1.4.6 libsvn_fs_base/note/structure:
> >> "At present, Subversion generally stores
> >> the youngest strings in "fulltext" form, and older strings as "delta"s
> >> against them (unless the delta would save no space compared to the
> >> fulltext).
> >> "
> >> My own experiments with SVN 1.4 code confirm that.
> >>
> >>
> >>
> >>> Repositories created with or 'svnadmin
> >>> upgrade'd by 1.6 and newer reverse this for new revisions of files
> >>> (while making sure not to introduce a dependency loop in the direction
> >>> of deltas).
> >>>
> >>> http://subversion.apache.org/docs/release-notes/1.6#bdb-forward-deltas
> >>>
> >>> On Friday, November 25, 2011 1:08 AM, "Vyacheslav Zholudev" <vy...@gmail.com> wrote:
> >>>> Hi,
> >>>>
> >>>> how does SVN 1.7.1 store fulltext and deltas in the BDB backend? From some time ago I remember that previous versions of SVN stored "almost" always a HEAD revision as fulltext, and others as reverse deltas.(except the case when a delta is bigger that fulltext) Was this behavior changed in SVN 1.7? I've looked at the notes about BDB and they don't differ almost at all from SVN 1.4's ones. Of course, I could look into the code more carefully, but my hope was that it wouldn't be a big deal to give me a short answer, if possible.
> >>>>
> >>>> Thanks in advance!
> >>>>
> >>>> Best,
> >>>> Vyacheslav
> >>>>
> >>>>
> >>>>
> >>
>
Re: BDB backend in SVN 1.7.1
Posted by Vyacheslav Zholudev <vy...@gmail.com>.
Hi Daniel,
would it be easy to change the code (I want to do it for my experiments) so that the HEAD (youngest) revisions are stored as fulltexts? Or is it something that was not foreseen by design to easily switch between approaches of representing history information?
Thanks,
Vyacheslav
On Nov 25, 2011, at 11:59 AM, Daniel Shahaf wrote:
> Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 11:13:00 +0100:
>>
>>> Old BDB-backed repositories stored the older revision as fulltext and
>>> newer revisions as deltas.
>>
>> Really?
>
> It seems that I should have swapped "older" and "newer" in the quoted
> sentence. Thanks for catching that.
>
>> Here is a quotation from SVN 1.4.6 libsvn_fs_base/note/structure:
>> "At present, Subversion generally stores
>> the youngest strings in "fulltext" form, and older strings as "delta"s
>> against them (unless the delta would save no space compared to the
>> fulltext).
>> "
>> My own experiments with SVN 1.4 code confirm that.
>>
>>
>>
>>> Repositories created with or 'svnadmin
>>> upgrade'd by 1.6 and newer reverse this for new revisions of files
>>> (while making sure not to introduce a dependency loop in the direction
>>> of deltas).
>>>
>>> http://subversion.apache.org/docs/release-notes/1.6#bdb-forward-deltas
>>>
>>> On Friday, November 25, 2011 1:08 AM, "Vyacheslav Zholudev" <vy...@gmail.com> wrote:
>>>> Hi,
>>>>
>>>> how does SVN 1.7.1 store fulltext and deltas in the BDB backend? From some time ago I remember that previous versions of SVN stored "almost" always a HEAD revision as fulltext, and others as reverse deltas.(except the case when a delta is bigger that fulltext) Was this behavior changed in SVN 1.7? I've looked at the notes about BDB and they don't differ almost at all from SVN 1.4's ones. Of course, I could look into the code more carefully, but my hope was that it wouldn't be a big deal to give me a short answer, if possible.
>>>>
>>>> Thanks in advance!
>>>>
>>>> Best,
>>>> Vyacheslav
>>>>
>>>>
>>>>
>>
Re: BDB backend in SVN 1.7.1
Posted by Daniel Shahaf <d....@daniel.shahaf.name>.
Vyacheslav Zholudev wrote on Fri, Nov 25, 2011 at 11:13:00 +0100:
>
> > Old BDB-backed repositories stored the older revision as fulltext and
> > newer revisions as deltas.
>
> Really?
It seems that I should have swapped "older" and "newer" in the quoted
sentence. Thanks for catching that.
> Here is a quotation from SVN 1.4.6 libsvn_fs_base/note/structure:
> "At present, Subversion generally stores
> the youngest strings in "fulltext" form, and older strings as "delta"s
> against them (unless the delta would save no space compared to the
> fulltext).
> "
> My own experiments with SVN 1.4 code confirm that.
>
>
>
> > Repositories created with or 'svnadmin
> > upgrade'd by 1.6 and newer reverse this for new revisions of files
> > (while making sure not to introduce a dependency loop in the direction
> > of deltas).
> >
> > http://subversion.apache.org/docs/release-notes/1.6#bdb-forward-deltas
> >
> > On Friday, November 25, 2011 1:08 AM, "Vyacheslav Zholudev" <vy...@gmail.com> wrote:
> >> Hi,
> >>
> >> how does SVN 1.7.1 store fulltext and deltas in the BDB backend? From some time ago I remember that previous versions of SVN stored "almost" always a HEAD revision as fulltext, and others as reverse deltas.(except the case when a delta is bigger that fulltext) Was this behavior changed in SVN 1.7? I've looked at the notes about BDB and they don't differ almost at all from SVN 1.4's ones. Of course, I could look into the code more carefully, but my hope was that it wouldn't be a big deal to give me a short answer, if possible.
> >>
> >> Thanks in advance!
> >>
> >> Best,
> >> Vyacheslav
> >>
> >>
> >>
>
Re: BDB backend in SVN 1.7.1
Posted by Vyacheslav Zholudev <vy...@gmail.com>.
> Old BDB-backed repositories stored the older revision as fulltext and
> newer revisions as deltas.
Really? Here is a quotation from SVN 1.4.6 libsvn_fs_base/note/structure:
"At present, Subversion generally stores
the youngest strings in "fulltext" form, and older strings as "delta"s
against them (unless the delta would save no space compared to the
fulltext).
"
My own experiments with SVN 1.4 code confirm that.
> Repositories created with or 'svnadmin
> upgrade'd by 1.6 and newer reverse this for new revisions of files
> (while making sure not to introduce a dependency loop in the direction
> of deltas).
>
> http://subversion.apache.org/docs/release-notes/1.6#bdb-forward-deltas
>
> On Friday, November 25, 2011 1:08 AM, "Vyacheslav Zholudev" <vy...@gmail.com> wrote:
>> Hi,
>>
>> how does SVN 1.7.1 store fulltext and deltas in the BDB backend? From some time ago I remember that previous versions of SVN stored "almost" always a HEAD revision as fulltext, and others as reverse deltas.(except the case when a delta is bigger that fulltext) Was this behavior changed in SVN 1.7? I've looked at the notes about BDB and they don't differ almost at all from SVN 1.4's ones. Of course, I could look into the code more carefully, but my hope was that it wouldn't be a big deal to give me a short answer, if possible.
>>
>> Thanks in advance!
>>
>> Best,
>> Vyacheslav
>>
>>
>>
Re: BDB backend in SVN 1.7.1
Posted by Daniel Shahaf <d....@daniel.shahaf.name>.
Old BDB-backed repositories stored the older revision as fulltext and
newer revisions as deltas. Repositories created with or 'svnadmin
upgrade'd by 1.6 and newer reverse this for new revisions of files
(while making sure not to introduce a dependency loop in the direction
of deltas).
http://subversion.apache.org/docs/release-notes/1.6#bdb-forward-deltas
On Friday, November 25, 2011 1:08 AM, "Vyacheslav Zholudev" <vy...@gmail.com> wrote:
> Hi,
>
> how does SVN 1.7.1 store fulltext and deltas in the BDB backend? From some time ago I remember that previous versions of SVN stored "almost" always a HEAD revision as fulltext, and others as reverse deltas.(except the case when a delta is bigger that fulltext) Was this behavior changed in SVN 1.7? I've looked at the notes about BDB and they don't differ almost at all from SVN 1.4's ones. Of course, I could look into the code more carefully, but my hope was that it wouldn't be a big deal to give me a short answer, if possible.
>
> Thanks in advance!
>
> Best,
> Vyacheslav
>
>
>