This improves the borg special remote memory usage, by
letting it only load one archive's worth of filenames into memory at a
time, and building up a larger tree out of the chunks.
When a borg repository has many archives, git-annex could easily OOM
before. Now, it will use only memory proportional to the number of
annexed keys in an archive.
Minor implementation wart: Each new chunk re-opens the content
identifier database, and also a new vector clock is used for each chunk.
This is a minor innefficiency only; the use of continuations makes
it hard to avoid, although putting the database handle into a Reader
monad would be one way to fix it.
It may later be possible to extend the ImportableContentsChunkable
interface to remotes that are not third-party populated. However, that
would perhaps need an interface that does not use continuations.
The ImportableContentsChunkable interface currently does not allow
populating the top of the tree with anything other than subtrees. It
would be easy to extend it to allow putting files in that tree, but borg
doesn't need that so I left it out for now.
Sponsored-by: Noam Kremen on Patreon
This eliminates the distinction between decodeBS and decodeBS', encodeBS
and encodeBS', etc. The old implementation truncated at NUL, and the
primed versions had to do extra work to avoid that problem. The new
implementation does not truncate at NUL, and is also a lot faster.
(Benchmarked at 2x faster for decodeBS and 3x for encodeBS; more for the
primed versions.)
Note that filepath-bytestring 1.4.2.1.8 contains the same optimisation,
and upgrading to it will speed up to/fromRawFilePath.
AFAIK, nothing relied on the old behavior of truncating at NUL. Some
code used the faster versions in places where I was sure there would not
be a NUL. So this change is unlikely to break anything.
Also, moved s2w8 and w82s out of the module, as they do not involve
filesystem encoding really.
Sponsored-by: Shae Erisson on Patreon
It was making the borgrepo path absolute.. even when it was a ssh
repository.
Made BorgRepo a newtype, to guard against accidentially treating it like a
FilePath.
Sponsored-by: Graham Spencer on Patreon
Note that a key with no size field that is hard linked will
result in listImportableContents reporting a file size of 0,
rather than the actual size of the file. One result is that
the progress meter when getting the file will seem to get stuck
at 100%. Another is that the remote's preferred content expression,
if it tries to match against file size, will treat it as an empty file.
I don't see a way to improve the latter behavior, and the former behavior
is a minor enough problem.
This commit was sponsored by Jake Vosloo on Patreon.
Keys stored on the filesystem are mangled by keyFile to avoid problem
chars. So, that mangling has to be reversed when parsing files from a
borg backup back to a key.
The directory special remote also so mangles them. Some other special
remotes do not; eg S3 just serializes the key -- but S3 object names are
not limited to filesystem valid filenames anyway, so a S3 server must
not map them directly to files in any case. It seems unlikely that a
borg backup of some such special remote will get broken by this change.
This commit was sponsored by Graham Spencer on Patreon.
Not yet used, but allows getting the size of items in the tree fairly
cheaply.
I noticed that CmdLine.Seek uses ls-tree and the feeds the files into
another long-running process to check their size. That would be an
example of a place that might be sped up by using this. Although in that
particular case, it only needs to know the size of unlocked files, not
locked. And since enabling --long probably doubles the ls-tree runtime
or more, the overhead of using it there may outwweigh the benefit.
This code I'm reverting works. But it has a problem: The export db and
log and the ContentIdentifier db and log still list the content as being
stored in the remote. So when I ran borg create again and stored the
content in borg again in a new archive, git-annex sync noticed that, but
since it didn't update the tree for the old archives, it then thought
the content that had been removed from them was still in them, and so
git-annex get failed in an ugly way:
Include pattern 'tmp/x/.git/annex/objects/pX/ZJ/SHA256E-s0--e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855/SHA256E-s0--e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855' never matched.
[2020-12-28 16:40:44.878952393] process [933616] done ExitFailure 1
user error (borg ["extract","/tmp/b::abs4","tmp/x/.git/annex/objects/pX/ZJ/SHA256E-s0--e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855/SHA256E-s0--e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"] exited 1)
It does not seem worth it to update the git tree for the export when dropping
content, that would make drop of many files very expensive in git tree objects
created. So, let's not support this I suppose..
Note that, after changing it with enableremote, syncing won't rescan
known archives in the borg repo using the changed config. Probably not a
problem?
Also used File in some places where filenames that could theoretically
start with - are passed to borg, to avoid it confusing them with
options.
This makes sync a lot faster in the common case where there's no new
backup.
There's still room for it to be faster. Currently the old imported tree
has to be traversed, to generate the ImportableContents. Which then
gets turned around to generate the new imported tree, which is
identical. So, it would be possible to just return a "no new imports",
or an ImportableContents that has a way to graft in a tree. The latter
is probably too far to go to optimise this, unless other things need it.
The former might be worth it, but it's already pretty fast, since git
ls-tree is pretty fast.
It's unusual to use a ContentIdentifier that is not semi-unique
for different contents. Note that in importKeys, it checks if a content
identifier is one that's known before, to avoid downloading the same
content twice. But that's done in a code path not used for borg repos,
because they are thirdpartypopulated.
Still some issues to deal with, see TODO and XXX.
Here's what gets logged, for each key:
cid log:
1608582045.832799227s 6720ebad-b20e-4460-a8f2-2477361aea75 !MjAyMC0xMi0yMVQxMTozMzoxNw==:!MjAyMC0xMi0yMVQxMzowNzoyNg==
The "!Mj" are base64 encoded borg archive names, since mine were
dates and contained some characters not allowed in cid logs unescaped.
There were archives that each contained the key. This list will grow as
more borg backups are done and learned about.
tree generated:
120000 blob 5ef6a4615c084819b44cd4e3a31657664ddf643b x/dotgit/annex/objects/06/mv/SHA256E-s30--a5d8532e64ec28f5491e25e7a6c1cb68f80507c1be6c1b35f8ec53d25413e5da/SHA256E-s30--a5d8532e64ec28f5491e25e7a6c1cb68f80507c1be6c1b35f8ec53d25413e5da
120000 blob 063a139d3021c8db60f5c576d29fada2b824d91c x/dotgit/annex/objects/72/PP/SHA256E-s30--e80b09a854b4e4d99a76caaa6983b34272480e0b4fdb95d04234a54b4849b893/SHA256E-s30--e80b09a854b4e4d99a76caaa6983b34272480e0b4fdb95d04234a54b4849b893
120000 blob b53b54916fd6abf21fedf796deca08d5ac7a75af x/dotgit/annex/objects/Ww/pk/SHA256E-s30--6aac072a8ebf02a5807c4f15e77ed585a6c87b3b333ba625a3c8d6b4dc50a9f2/SHA256E-s30--6aac072a8ebf02a5807c4f15e77ed585a6c87b3b333ba625a3c8d6b4dc50a9f2
This commit was sponsored by Denis Dzyubenko on Patreon.
