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 adds the overhead of a copy when serializing and deserializing keys.
I have not benchmarked much, but runtimes seem barely changed at all by that.
When a lot of keys are in memory, it improves memory use.
And, it prevents keys sometimes getting PINNED in memory and failing to GC,
which is a problem ByteString has sometimes. In particular, git-annex sync
from a borg special remote had that problem and this improved its memory
use by a large amount.
Sponsored-by: Shae Erisson on Patreon
This adds the overhead of a copy whenever converting to/from ExportLocation and
ImportLocation.
borg: Some improvements to memory use when importing a lot of archives.
(It's still pretty bad.)
Sponsored-by: Mark Reidenbach on Patreon
sync --content: Avoid a redundant checksum of a file that was
incrementally verified, when used on NTFS and perhaps other filesystems.
When sync has just gotten the content, it does not need to check inAnnex a
second time. On NTFS, for some reason the write of the inode cache after
it gets the content is not immediately able to be read, and with an
empty/non-matching inode cache due to that stale data, inAnnex falls back
to hashing the whole object to determine if it's present.
Sponsored-by: Brock Spratlen on Patreon
Disabling git-annex branch update for this command is
ok, because it does not use any information from the branch,
but only logs the location when it adds a key.
Sponsored-by: Dartmouth College's Datalad project
