This changes the database structure to use one database per folder, with
a small main database to coordinate. Reverts the prior change to buffer
all files in memory when pulling, meaning there is now a phase where the
WAL file will grow significantly, at least for initial sync of folders
with many directories.
---------
Co-authored-by: bt90 <btom1990@googlemail.com>
This reduces the number of file entries we carry in the database,
sometimes significantly. The downside is that if a file is deleted while
a device is offline, and that device comes back more than the cutoff
interval (six months) later, those files will get resurrected at some
point.
The current limit is far too low for our workloads. Perhaps we should
aim even higher than the 64MiB this patch proposes?
Citing the sqlite docs:
> [...] after committing a transaction the rollback journal file may
remain in the file-system. **This increases performance for subsequent
transactions since overwriting an existing file is faster than append to
a file**, but it also consumes file-system space.
tl;dr: if the limit is too low, we're shooting ourselves in the foot in
terms of performance.
Switch the database from LevelDB to SQLite, for greater stability and
simpler code.
Co-authored-by: Tommy van der Vorst <tommy@pixelspark.nl>
Co-authored-by: bt90 <btom1990@googlemail.com>
We've had weak/rolling hashing in the code for quite a while. It was a
popular request for a while, based on the belief that rsync does this
and we should too. However, the benefit is quite small; we save on
average about 0.8% of transferred blocks over the population as a whole:
<img width="974" alt="Screenshot 2025-03-28 at 17 09 02"
src="https://github.com/user-attachments/assets/bbe10dea-f85e-4043-9823-7cef1220b4a2"
/>
This would be fine if the cost was comparably low, however the downside
of attempting rolling hash matching is that we (by default) do a
complete file read on the destination in order to look for matches
before we starting pulling blocks for the file. For any larger file this
means a sometimes long, I/O-intensive pause before the file starts
syncing, for usually no benefit.
I propose we simply rip off the bandaid and save the effort.
At a high level, this is what I've done and why:
- I'm moving the protobuf generation for the `protocol`, `discovery` and
`db` packages to the modern alternatives, and using `buf` to generate
because it's nice and simple.
- After trying various approaches on how to integrate the new types with
the existing code, I opted for splitting off our own data model types
from the on-the-wire generated types. This means we can have a
`FileInfo` type with nicer ergonomics and lots of methods, while the
protobuf generated type stays clean and close to the wire protocol. It
does mean copying between the two when required, which certainly adds a
small amount of inefficiency. If we want to walk this back in the future
and use the raw generated type throughout, that's possible, this however
makes the refactor smaller (!) as it doesn't change everything about the
type for everyone at the same time.
- I have simply removed in cold blood a significant number of old
database migrations. These depended on previous generations of generated
messages of various kinds and were annoying to support in the new
fashion. The oldest supported database version now is the one from
Syncthing 1.9.0 from Sep 7, 2020.
- I changed config structs to be regular manually defined structs.
For the sake of discussion, some things I tried that turned out not to
work...
### Embedding / wrapping
Embedding the protobuf generated structs in our existing types as a data
container and keeping our methods and stuff:
```
package protocol
type FileInfo struct {
*generated.FileInfo
}
```
This generates a lot of problems because the internal shape of the
generated struct is quite different (different names, different types,
more pointers), because initializing it doesn't work like you'd expect
(i.e., you end up with an embedded nil pointer and a panic), and because
the types of child types don't get wrapped. That is, even if we also
have a similar wrapper around a `Vector`, that's not the type you get
when accessing `someFileInfo.Version`, you get the `*generated.Vector`
that doesn't have methods, etc.
### Aliasing
```
package protocol
type FileInfo = generated.FileInfo
```
Doesn't help because you can't attach methods to it, plus all the above.
### Generating the types into the target package like we do now and
attaching methods
This fails because of the different shape of the generated type (as in
the embedding case above) plus the generated struct already has a bunch
of methods that we can't necessarily override properly (like `String()`
and a bunch of getters).
### Methods to functions
I considered just moving all the methods we attach to functions in a
specific package, so that for example
```
package protocol
func (f FileInfo) Equal(other FileInfo) bool
```
would become
```
package fileinfos
func Equal(a, b *generated.FileInfo) bool
```
and this would mostly work, but becomes quite verbose and cumbersome,
and somewhat limits discoverability (you can't see what methods are
available on the type in auto completions, etc). In the end I did this
in some cases, like in the database layer where a lot of things like
`func (fv *FileVersion) IsEmpty() bool` becomes `func fvIsEmpty(fv
*generated.FileVersion)` because they were anyway just internal methods.
Fixes#8247
Setting "Sync Protocol Listen Addresses" and "Global Discovery
Server" in the Settings dialog does not work. This bug seems to
have been introduced in 26d52be.
This sends the Cache-Control header to allow caching of static resources,
and checks the If-Modified-Since header to allow browser to use the
cached resource on refresh. Also fixes some paths that caused redirects
(core//foo -> core/foo)
Without this, as soon as we'd touched 1000 files in the last minute
(which can happen), we got stuck doing cache cleaning all the time,
burning a lot of CPU time.
This captures the common pattern of writing to a temp file and moving it
to it's real name only if everything went well. It reduces the amount of
code in some places where we do this, but maybe not as much as I
expected because the upgrade thing is still a special snowflake...
commit d60fbce311
Author: Jacek Szafarkiewicz <szafar@linux.pl>
Date: Mon Jun 1 11:16:36 2015 +0200
Correct order of deb files
commit 3b2ecfcc45
Merge: f4daebbc23a601
Author: Jacek Szafarkiewicz <szafar@linux.pl>
Date: Mon Jun 1 11:15:06 2015 +0200
Merge github.com:syncthing/syncthing
Conflicts:
build.go
commit f4daebb851
Author: Jacek Szafarkiewicz <szafar@linux.pl>
Date: Tue May 26 12:58:25 2015 +0200
Add me to AUTHORS
commit 9e77f4bea0
Author: Jacek Szafarkiewicz <szafar@linux.pl>
Date: Tue May 26 12:57:40 2015 +0200
Add systemd files to deb packate
