Commit Graph

73 Commits

Author SHA1 Message Date
Simon Frei
cc2a55892f
lib: Repair sequence inconsistencies (#6367) 2020-03-18 17:34:46 +01:00
Simon Frei
1bd4ea0cbb
lib/db: Don't ignore failures unmarshaling version lists (#6411) 2020-03-16 10:09:27 +01:00
Jakob Borg
c08e253e7c
lib/db: Prevent GC concurrently with migration (fixes #6389) (#6390) 2020-02-29 19:51:32 +01:00
Jakob Borg
883497966e lib/db: Remove reference to env var that never existed 2020-02-27 11:21:35 +01:00
Jakob Borg
4f7a77597e
lib/db: Slightly improve indirection (ref #6372) (#6373)
I was working on indirecting version vectors, and that resulted in some
refactoring and improving the existing block indirection stuff. We may
or may not end up doing the version vector indirection, but I think
these changes are reasonable anyhow and will simplify the diff
significantly if we do go there. The main points are:

- A bunch of renaming to make the indirection and GC not about "blocks"
  but about "indirection".

- Adding a cutoff so that we don't actually indirect for small block
  lists. This gets us better performance when handling small files as it
  cuts out the indirection for quite small loss in space efficiency.

- Being paranoid and always recalculating the hash on put. This costs
  some CPU, but the consequences if a buggy or malicious implementation
  silently substituted the block list by lying about the hash would be bad.
2020-02-27 11:19:21 +01:00
Jakob Borg
6a840a040b
lib/db: Keep metadata better in sync (ref #6335) (#6337)
This adds metadata updates to the same write batch as the underlying
file change. The odds of a metadata update going missing is greatly
reduced.

Bonus change: actually commit the transaction in recalcMeta.
2020-02-13 15:23:08 +01:00
Jakob Borg
a728743c86
lib/db: Use Commit() instead of commit() (#6330)
The readWriteTransaction offered both commit() (the one to use) and
Commit() (via embedding) where the latter didn't close the read
transaction. This removes the lower cased variant in order to prevent
the mistake.

The only place where the mistake was made was the new gc runner, where
it would leave a read snapshot open forever.
2020-02-12 11:59:55 +01:00
Jakob Borg
04e648fee6
lib/db: Handle missing block lists as missing file (ref #6321) (#6322)
Also explicitly handle non-nil but empty block lists (if they should
ever pop up as an effect of unmarshalling changes or whatnot).
2020-02-11 15:37:22 +01:00
Jakob Borg
84920bff63 lib/db: Fixup last commit with better key name 2020-01-26 15:22:21 +01:00
Jakob Borg
bf4c8439e8
lib/db: Configurable block GC time (#6295)
Also retain the interval over restarts by storing last GC time in the
database. This to make sure that GC eventually happens even if the
interval is configured to a long time (say, a month).
2020-01-26 15:13:28 +01:00
Jakob Borg
8fc2dfad0c
lib/db: Deduplicate block lists in database (fixes #5898) (#6283)
* lib/db: Deduplicate block lists in database (fixes #5898)

This moves the block list in the database out from being just a field on
the FileInfo to being an object of its own. When putting a FileInfo we
marshal the block list separately and store it keyed by the sha256 of
the marshalled block list. When getting, if we are not doing a
"truncated" get, we do an extra read and unmarshal for the block list.

Old block lists are cleared out by a periodic GC sweep. The alternative
would be to use refcounting, but:

- There is a larger risk of getting that wrong and either dropping a
  block list in error or keeping them around forever.

- It's tricky with our current database, as we don't have dirty reads.
  This means that if we update two FileInfos with identical block lists in
  the same transaction we can't just do read/modify/write for the ref
  counters as we wouldn't see our own first update. See above about
  tracking this and risks about getting it wrong.

GC uses a bloom filter for keys to avoid heavy RAM usage. GC can't run
concurrently with FileInfo updates so there is a new lock around those
operation at the lowlevel.

The end result is a much more compact database, especially for setups
with many peers where files get duplicated many times.

This is per-key-class stats for a large database I'm currently working
with, under the current schema:

```
 0x00:  9138161 items, 870876 KB keys + 7397482 KB data, 95 B +  809 B avg, 1637651 B max
 0x01:   185656 items,  10388 KB keys + 1790909 KB data, 55 B + 9646 B avg,  924525 B max
 0x02:   916890 items,  84795 KB keys +    3667 KB data, 92 B +    4 B avg,     192 B max
 0x03:      384 items,     27 KB keys +       5 KB data, 72 B +   15 B avg,      87 B max
 0x04:     1109 items,     17 KB keys +      17 KB data, 15 B +   15 B avg,      69 B max
 0x06:      383 items,      3 KB keys +       0 KB data,  9 B +    2 B avg,      18 B max
 0x07:      510 items,      4 KB keys +      12 KB data,  9 B +   24 B avg,      41 B max
 0x08:     1349 items,     12 KB keys +      10 KB data,  9 B +    8 B avg,      17 B max
 0x09:      194 items,      0 KB keys +     123 KB data,  5 B +  634 B avg,   11484 B max
 0x0a:        3 items,      0 KB keys +       0 KB data, 14 B +    7 B avg,      30 B max
 0x0b:   181836 items,   2363 KB keys +   10694 KB data, 13 B +   58 B avg,     173 B max
 Total 10426475 items, 968490 KB keys + 9202925 KB data.
```

Note 7.4 GB of data in class 00, total size 9.2 GB. After running the
migration we get this instead:

```
 0x00:  9138161 items, 870876 KB keys + 2611392 KB data, 95 B +  285 B avg,    4788 B max
 0x01:   185656 items,  10388 KB keys + 1790909 KB data, 55 B + 9646 B avg,  924525 B max
 0x02:   916890 items,  84795 KB keys +    3667 KB data, 92 B +    4 B avg,     192 B max
 0x03:      384 items,     27 KB keys +       5 KB data, 72 B +   15 B avg,      87 B max
 0x04:     1109 items,     17 KB keys +      17 KB data, 15 B +   15 B avg,      69 B max
 0x06:      383 items,      3 KB keys +       0 KB data,  9 B +    2 B avg,      18 B max
 0x07:      510 items,      4 KB keys +      12 KB data,  9 B +   24 B avg,      41 B max
 0x09:      194 items,      0 KB keys +     123 KB data,  5 B +  634 B avg,   11484 B max
 0x0a:        3 items,      0 KB keys +       0 KB data, 14 B +   17 B avg,      51 B max
 0x0b:   181836 items,   2363 KB keys +   10694 KB data, 13 B +   58 B avg,     173 B max
 0x0d:    44282 items,   1461 KB keys +   61081 KB data, 33 B + 1379 B avg, 1637399 B max
 Total 10469408 items, 969939 KB keys + 4477905 KB data.
```

Class 00 is now down to 2.6 GB, with just 61 MB added in class 0d.

There will be some additional reads in some cases which theoretically
hurts performance, but this will be more than compensated for by smaller
writes and better compaction.

On my own home setup which just has three devices and a handful of
folders the difference is smaller in absolute numbers of course, but
still less than half the old size:

```
 0x00:  297122 items,  20894 KB keys + 306860 KB data, 70 B + 1032 B avg, 103237 B max
 0x01:  115299 items,   7738 KB keys +  17542 KB data, 67 B +  152 B avg,    419 B max
 0x02: 1430537 items, 121223 KB keys +   5722 KB data, 84 B +    4 B avg,    253 B max
 ...
 Total 1947412 items, 151268 KB keys + 337485 KB data.
```

to:

```
 0x00:  297122 items,  20894 KB keys +  37038 KB data, 70 B +  124 B avg,    520 B max
 0x01:  115299 items,   7738 KB keys +  17542 KB data, 67 B +  152 B avg,    419 B max
 0x02: 1430537 items, 121223 KB keys +   5722 KB data, 84 B +    4 B avg,    253 B max
 ...
 0x0d:   18041 items,    595 KB keys +  71964 KB data, 33 B + 3988 B avg, 101109 B max
 Total 1965447 items, 151863 KB keys + 139628 KB data.
```

* wip

* wip

* wip

* wip
2020-01-24 08:35:44 +01:00
Simon Frei
08f0e125ef all: Transactionalize db.FileSet (fixes #5952) (#6239) 2020-01-21 18:23:08 +01:00
Simon Frei
0bec01b827 lib/db: Remove *instance by making everything *Lowlevel (#6204) 2019-12-02 08:18:04 +01:00
Jakob Borg
c71116ee94
Implement database abstraction, error checking (ref #5907) (#6107)
This PR does two things, because one lead to the other:

- Move the leveldb specific stuff into a small "backend" package that
defines a backend interface and the leveldb implementation. This allows,
potentially, in the future, switching the db implementation so another
KV store should we wish to do so.

- Add proper error handling all along the way. The db and backend
packages are now errcheck clean. However, I drew the line at modifying
the FileSet API in order to keep this manageable and not continue
refactoring all of the rest of Syncthing. As such, the FileSet methods
still panic on database errors, except for the "database is closed"
error which is instead handled by silently returning as quickly as
possible, with the assumption that we're anyway "on the way out".
2019-11-29 09:11:52 +01:00
Jakob Borg
755e689627 lib/db: Always use small db settings on 32 bit archs (#6053) 2019-10-03 13:40:14 +01:00
Jakob Borg
90b70c7a16 lib/db: Use different defaults for larger databases (fixes #5966) (#5967)
This introduces a better set of defaults for large databases. I've
experimentally determined that it results in much better throughput in a
couple of scenarios with large databases, but I can't give any
guarantees the values are always optimal. They're probably no worse than
the defaults though.
2019-08-20 09:41:41 +02:00
Jakob Borg
a992559abc
lib/db: Add hacky way to adjust database parameters (#5889)
This adds a set of magical environment variables that can be used to
tweak the database parameters. It's totally undocumented and not
intended to be a long term or supported thing.

It's ugly, but there is a backstory. I have a couple of large
installations where the database options are inefficient or otherwise
suboptimal (24/7 compaction going on and stuff like that). I don't
*know* the correct database parameters, nor yet the formula or method to
derive them by, so this requires experimentation. Experimentation needs
to happen partly in production, and rolling out new builds for every
tweak isn't practical. This provides override points for all reasonable
values, while not changing anything by default.

Ideally, at the end of such experimentation, we'll know which values are
relevant to change and in what manner, and can provide a more user
friendly knob to do so - or do it automatically based on the database
size.
2019-07-26 22:18:42 +02:00
Simon Frei
bf744ded31 cmd/syncthing, lib/db: Exit/close db faster (fixes #5781) (#5782)
This adds a 10s timeout on closing the db and additionally cancels active
db iterators and waits for them to terminate before closing the db.
2019-06-17 15:27:25 +03:00
Simon Frei
fe4daf242b
cmd, lib/db: Actually close goleveldb (fixes #5505) (#5671) 2019-05-02 11:15:00 +02:00
Simon Frei
ca3ae64bbf lib/db: Flush batch based on size and refactor (fixes #5531) (#5536)
Flush the batch when exceeding a certain size, instead of when reaching a number
of batched operations.
Move batch to lowlevel to be able to use it in NamespacedKV.
Increase the leveldb memory buffer from 4 to 16 MiB.
2019-02-14 23:15:13 +00:00
Jakob Borg
04fdafa280 lib/db, lib/model: Remove dead code (#5517) 2019-02-08 16:42:58 +01:00
Jakob Borg
7b0c49a1b6 cmd/stindex: Add index checking mode ("idxck") (#5262) 2018-10-11 20:48:39 +01:00
Jakob Borg
b50d57b7fd
lib/db: Refactor: use a Lowlevel type underneath Instance (ref #5198) (#5212)
This adds a thin type that holds the state associated with the
leveldb.DB, leaving the huge Instance type more or less stateless. Also
moves some keying stuff into the DB package so that other packages need
not know the keying specifics.

(This does not, yet, fix the cmd/stindex program, in order to keep the
diff size down. Hence the keying constants are still exported.)
2018-10-10 11:34:24 +02:00