We can either preallocate storage for a file or sparsify it. This
detects a pack file as sparse if it contains an all zero block or
consists of only one block. As the file sparsification is just an
approximation, hide it behind a `--sparse` parameter.
Use runtime.GOMAXPROCS(0) as worker count for CPU-bound tasks,
repo.Connections() for IO-bound task and a combination if a task can be
both. Streaming packs is treated as IO-bound as adding more worker
cannot provide a speedup.
Typical IO-bound tasks are download / uploading / deleting files.
Decoding / Encoding / Verifying are usually CPU-bound. Several tasks are
a combination of both, e.g. for combined download and decode functions.
In the latter case add both limits together. As the backends have their
own concurrency limits restic still won't download more than
repo.Connections() files in parallel, but the additional workers can
decode already downloaded data in parallel.
Much simpler implementation that guarantees each required pack
is downloaded only once (and hence does not need to manage
pack cache). Also improves large file restore performance.
Signed-off-by: Igor Fedorenko <igor@ifedorenko.com>
don't create fileInfo structs for empty files. this saves memory.
this also avoids extra serial scan of all fileInfo, which should
make restore faster and more consistent.
Signed-off-by: Igor Fedorenko <igor@ifedorenko.com>
reworked restore error callback to use file location
path instead of much heavier Node. this reduced restore
memory usage by as much as 50% in some of my tests.
Signed-off-by: Igor Fedorenko <igor@ifedorenko.com>
* uses less memory as common prefix is only stored once
* stepping stone for simpler error callback api, which
will allow further memory footprint reduction
Signed-off-by: Igor Fedorenko <igor@ifedorenko.com>
traverseTree() was meant to call enterDir() whenever a directory is
selected for restore, either explicitly or implicitly (=contains a file
which is to be restored). After restoring a file, leaveDir() is called
in reverse order for all intermediate directories so that the metadata
can be restored.
When a directory is selected implicitly, the metadata for it is
restored. This is different from the previous restorer behavior, which
created implicitly selected intermediate directories with permissions
0700 (only user can read/write it).
This commit changes the behavior back to the old one. Only a directory
is explicitly selected for restore, enterDir()/leaveDir() are called for
it. Otherwise, only visitNode() is called, so visitNode() needs to make
sure the parent directory exists. If the directory is explicitly
included, leaveDir() will then restore the metadata correctly.
When we decide to change the behavior (restore metadata for all
intermediate directories, even if selected implicitly), we should do
that in the selection functions, not here.
This finally resolves #1870
