Commit Graph

185 Commits (16bd5c8ebe503a7279fccce85e39fc6e22349583)

Author SHA1 Message Date
beorn7 2235cec175 Handle fingerprint collisions. 2015-05-07 18:17:59 +02:00
beorn7 9820e5fe99 Use FastFingerprint where appropriate. 2015-05-06 12:00:58 +02:00
beorn7 c5fa0b90c3 Fix the case where a series in memory has 0 chunks, but chunks on disk.
This is actually completely normal for a freshly unarchived series.

Test added to expose.
2015-04-09 15:57:11 +02:00
beorn7 3035b8bfdd Adaptively reduce the wait time for memory series maintenance.
This will make in-memory series maintenance the faster the more chunks
are waiting for persistence.
2015-04-01 17:52:03 +02:00
beorn7 6a21f73898 Fixes after review. 2015-03-19 17:54:59 +01:00
beorn7 51d35f4481 Instrument series maintenance durations. 2015-03-19 17:06:16 +01:00
beorn7 12ae6e9203 Increase resilience of the storage against data corruption - step 4.
Step 4: Add a configurable sync'ing of series files after modification.
2015-03-19 15:58:02 +01:00
beorn7 11bd9ce1bd Increase resilience of the storage against data corruption - step 3.
Step 3: Remember the mtime of series files and make use of it to
detect series files that are not the one the checkpoint thinks they
are.
2015-03-19 15:44:11 +01:00
beorn7 e25cca823c Increase resilience of the storage against data corruption - step 2.
Step 2: Add a flag -storage.local.pedantic-checks to check every
series file.

Also, remove countPersistedHeadChunks channel, which is unused.
2015-03-19 12:06:15 +01:00
beorn7 3d8d8928be Increase resilience of the storage against data corruption - step 1.
Step 1: Admit the problem by turning the various "panic"s into logged
errors, followed by marking the persistence as dirty.
2015-03-19 11:49:18 +01:00
beorn7 da7c0461c6 Rename persist queue len/cap to num/max chunks to persist.
Remove deprecated flag storage.incoming-samples-queue-capacity.
2015-03-18 19:36:41 +01:00
beorn7 a075900f9a Merge branch 'beorn7/persistence' into beorn7/ingestion-tweaks 2015-03-18 19:09:31 +01:00
beorn7 1d8fc7d56f Change minor things after code review. 2015-03-18 19:09:07 +01:00
beorn7 be11cb2b07 Remove the sample ingestion channel.
The one central sample ingestion channel has caused a variety of
trouble. This commit removes it. Targets and rule evaluation call an
Append method directly now. To incorporate multiple storage backends
(like OpenTSDB), storage.Tee forks the Append into two different
appenders.

Note that the tsdb queue manager had its own queue anyway. It was a
queue after a queue... Much queue, so overhead...

Targets have their own little buffer (implemented as a channel) to
avoid stalling during an http scrape. But a new scrape will only be
started once the old one is fully ingested.

The contraption of three pipelined ingesters was removed. A Target is
an ingester itself now. Despite more logic in Target, things should be
less confusing now.

Also, remove lint and vet warnings in ast.go.
2015-03-15 14:08:22 +01:00
beorn7 0056eaeb4f Redesign series maintenance and chunk persistence. 2015-03-14 22:05:23 +01:00
beorn7 5bea942d8e Improve various things around chunk encoding.
A number of mostly minor things:

- Rename chunk type -> chunk encoding.

- After all, do not carry around the chunk encoding to all parts of
  the system, but just have one place where the encoding for new
  chunks is set based on the flag. The new approach has caveats as
  well, but the polution of so many method signatures is worse.

- Use the default chunk encoding for new chunks of existing
  series. (Previously, only new _series_ would get chunks with the
  default encoding.)

- Use an enum for chunk encoding. (But keep the version number for the
  flag, for reasons discussed previously.)

- Add encoding() to the chunk interface (so that a chunk knows its own
  encoding - no need to have that in a different top-level function).

- Got rid of newFollowUpChunk (which would keep the existing encoding
  for all chunks of a time series). Now only use newChunk(), which
  will create a chunk encoding according to the flag.

- Simplified transcodeAndAdd.

- Reordered methods of deltaEncodedChunk and doubleDeltaEncoded chunk
  to match the order in the chunk interface.

- Only transcode if the chunk is not yet half full. If more than half
  full, add a new chunk instead.
2015-03-14 19:03:20 +01:00
beorn7 13fcf1ddbc Implement double-delta encoded chunks. 2015-03-05 20:33:26 +01:00
beorn7 5ed8f6c205 Update persistQueueLength after chunks were persisted. 2015-03-04 18:46:16 +01:00
beorn7 1db7589081 Reduce the capacity of countPersistedHeadChunks.
The capacity is basically how many persisted head chunks we will count
at most while doing other things, in particular checkpointing. To
limit the amount of already counted head chunks, keep this number low,
otherwise we will easily checkpoint too often if checkpoints take long
anyway.
2015-02-27 00:53:52 +01:00
beorn7 9406afad72 Do not double-count non-persisted head chunks on loading. 2015-02-27 00:06:16 +01:00
beorn7 dbc22b972c Check last time in head chunk for head chunk timeout, not first. 2015-02-26 23:40:42 +01:00
beorn7 edd716e63c Fix the embarrassing bug introduced in commit 0851945.
In that commit, the 'maintainSeries' call was accidentally removed.

This commit refactors things a bit so that there is now a clean
'maintainMemorySeries' and a 'maintainArchivedSeries' call.

Straighten the nomenclature a bit (consistently use 'drop' for
chunks and 'purge' for series/metrics).

Remove the annoying 'Completed maintenance sweep through archived
fingerprints' message if there were no archived fingerprints to do
maintenance on.
2015-02-26 18:30:33 +01:00
beorn7 af91fb8e31 Improve persisting chunks to disk.
This is done by bucketing chunks by fingerprint. If the persisting to
disk falls behind, more and more chunks are in the queue. As soon as
there are "double hits", we will now persist both chunks in one go,
doubling the disk throughput (assuming it is limited by disk
seeks). Should even more pile up so that we end wit "triple hits", we
will persist those first, and so on.

Even if we have millions of time series, this will still help,
assuming not all of them are growing with the same speed. Series that
get many samples and/or are not very compressable will accumulate
chunks faster, and they will soon get double- or triple-writes.

To improve the chance of double writes,
-storage.local.persistence-queue-capacity could be set to a higher
value. However, that will slow down shutdown a lot (as the queue has
to be worked through). So we leave it to the user to set it to a
really high value. A more fundamental solution would be to checkpoint
not only head chunks, but also chunks still in the persist queue. That
would be quite complicated for a rather limited use-case (running many
time series with high ingestion rate on slow spinning disks).
2015-02-17 16:02:09 +01:00
beorn7 e22f26bc58 Move to a queue model for appending samples after all.
Starting a goroutine takes 1-2µs on my laptop. From the "numbers every
Go programmer should know", I had 300ns for a channel send in my
mind. Turns out, on my laptop, it takes only 60ns. That's fast enough
to warrant the machinery of yet another channel with a fixed set of
worker goroutines feeding from it. The number chosen (8 for now) is
low enough to not really afflict a measurable overhead (a big
Prometheus server has >1000 goroutines running), but high enough to
not make sample ingestion a bottleneck.
2015-02-13 14:26:54 +01:00
beorn7 fe518fdb28 Simplify AppendSamples by allowing it to be goroutine-unsafe. 2015-02-13 12:13:22 +01:00
beorn7 5d3cd65a5d Improve performance of ingestion.
- Parallelize AppendSamples as much as possible without breaking the
  contract about temporal order.

- Allocate more fingerprint locker slots.

- Do not run early checkpoints if we are behind on chunk persistence.

- Increase fpMinWaitDuration to give the disk more time for more
  important things.

Also, switch math.MaxInt64 and math.MinInt64 to the new constants.
2015-02-12 18:12:37 +01:00
beorn7 d2ab49c396 Make the persist queue length configurable.
Also, set a much higher default value.

Chunk persist requests can be quite spiky. If you collect a large
number of time series that are very similar, they will tend to finish
up a chunk at about the same time. There is no reason we need to back
up scraping just because of that. The rationale of the new default
value is "1/8 of the chunks in memory".
2015-02-06 14:54:53 +01:00
Julius Volz 9412b296d5 Remove labels on persist error counter.
This fixes https://github.com/prometheus/prometheus/issues/496
2015-02-01 14:03:34 +01:00
Bjoern Rabenstein 2c8fdcbc23 Remove a deadlock during shutdown.
If queries are still running when the shutdown is initiated, they will
finish _during_ the shutdown. In that case, they might request chunk
eviction upon unpinning their pinned chunks. That might completely
fill the evict request queue _after_ draining it during storage
shutdown. If that ever happens (which is the case if there are _many_
queries still running during shutdown), the affected queries will be
stuck while keeping a fingerprint locked. The checkpointing can then
not process that fingerprint (or one that shares the same lock). And
then we are deadlocked.
2015-01-22 14:42:15 +01:00
Bjoern Rabenstein 5859b74f1b Clean up license issues.
- Move CONTRIBUTORS.md to the more common AUTHORS.
- Added the required NOTICE file.
- Changed "Prometheus Team" to "The Prometheus Authors".
- Reverted the erroneous changes to the Apache License.
2015-01-21 20:07:45 +01:00
Julius Volz a6bc42bc61 Minor formatting/spelling fixups. 2015-01-09 11:04:20 +01:00
Bjoern Rabenstein 0851945054 Add a heuristics to checkpoint early if there are many "dirty" series.. 2015-01-08 20:15:58 +01:00
Bjoern Rabenstein 622e8350cd Fix a bug handling freshly unarchived series.
Usually, if you unarchive a series, it is to add something to it,
which will create a new head chunk. However, if a series in
unarchived, and before anything is added to it, it is handled by the
maintenance loop, it will be archived again. In that case, we have to
load the chunkDescs to know the lastTime of the series to be
archived. Usually, this case will happen only rarely (as a race, has
never happened so far, possibly because the locking around unarchiving
and the subsequent sample append is smart enough). However, during
crash recovery, we sometimes treat series as "freshly unarchived"
without directly appending a sample. We might add more cases of that
type later, so better deal with archiving properly and load chunkDescs
if required.
2015-01-08 16:25:50 +01:00
Bjoern Rabenstein eb932d1524 Remove a deadlock during shutdown. 2015-01-07 19:02:38 +01:00
Brian Brazil e56786b221 Have scrape time as a pseudovariable, not a prometheus variable.
This ensures it has the right timestamp, and is easier to work with.

Switch sd variable away from 'outcome', using total/failed instead.
2014-12-27 00:39:33 +00:00
Julius Volz c9618d11e8 Introduce copy-on-write for metrics in AST.
This depends on changes in:

https://github.com/prometheus/client_golang/tree/cow-metrics.

Change-Id: I80b94833a60ddf954c7cd92fd2cfbebd8dd46142
2014-12-12 20:34:55 +01:00
Bjoern Rabenstein 674624f1c8 Completed more TODOs.
- Documented checkpoint file format.
- High-level description of series sanitation.
- Replace fp.LoadFromString panic with an error.
  (Change in client_golang already submitted.)
- Introduced checks for series file size where appropriate.
- Removed two Law of Demeter violations.

Change-Id: I555d97a2c8f4769820c2fc8bf5d6f4e160222abc
2014-11-27 20:46:45 +01:00
Bjoern Rabenstein 7d11019aa2 Squash a few trivial TODOs.
- Delete unneeded file view_adapter.go.
- Assessed that we still need the fingerprints in nodes
  (to create iterators).
- Turned numMemChunkDescs into a metric.

Change-Id: I29be963c795a075ec00c095f76bf26405535609d
2014-11-27 18:26:06 +01:00
Bjoern Rabenstein 14bda4180c Changes after pair code review.
Change-Id: Ib72d40f8e9027818cfbbd32a7a7201eebda07455
2014-11-25 17:12:59 +01:00
Bjoern Rabenstein 9ea808cd8b Remove debug log line.
Change-Id: Icdd2351b89f2d37ac2b615f9cf872e054c694ad1
2014-11-25 17:10:39 +01:00
Bjoern Rabenstein bb42cc2e2d Evict based on memory pressure. Evict recently used chunks last.
Change-Id: Ie6168f0cdb3917bdc63b6fe15585dd70c1e42afe
2014-11-25 17:10:39 +01:00
Bjoern Rabenstein d73e851b14 Tweak timing in the maintenance loop.
Change-Id: I9801c4f9a22c3b3dc1ce1af81fdd9e992a4f4dd7
2014-11-25 17:10:39 +01:00
Bjoern Rabenstein 2672aa8ece Instrument series maintenance.
Change-Id: Ie4269d07ad4d23d44230c95a523088b472718e54
2014-11-25 17:10:39 +01:00
Bjoern Rabenstein 74c143c4c9 Improve scraper shutdown time.
- Stop target pools in parallel.
- Stop individual scrapers in goroutines, too.
- Timing tweaks.

Change-Id: I9dff1ee18616694f14b04408eaf1625d0f989696
2014-11-25 17:10:39 +01:00
Bjoern Rabenstein 3f61d304ce Reorganize maintenance loop.
Change-Id: Iac10f988ba3e93ffb188f49c30f92e0b6adce5a3
2014-11-25 17:10:30 +01:00
Bjoern Rabenstein c087ee35f7 Remove archiveMtx.
Change-Id: Ie8019f860bbda68621f74380c90a4e57930d3d7a
2014-11-25 17:10:30 +01:00
Bjoern Rabenstein 7af42eda65 Optimize purging.
Now only purge if there is something to purge.
Also, set savedFirstTime and archived time range appropriately.
(Which is needed for the optimization.)

Change-Id: Idcd33319a84def3ce0318d886f10c6800369e7f9
2014-11-25 17:10:30 +01:00
Bjoern Rabenstein 904acd43da Add crash recovery.
Fix the behavior if preload for non-existent series is requested.

Instead of returning an error (which triggers a panic further up),
simply count those incidents. They can happen regularly, we just want
to know if they happen too frequently because that would mean the
indexing is behind or broken.

Change-Id: I4b2d1b93c4146eeea897d188063cb9574a270f8b
2014-11-25 17:09:43 +01:00
Bjoern Rabenstein 4efc60174b Tweak and verify a few parameters.
Remove TODOs accordingly.

Change-Id: Ic062e13b6ae89a9135d3f14011114fe1cca1cef8
2014-11-25 17:09:43 +01:00
Bjoern Rabenstein 5f8e9617ef Add more tests.
Add an end-to-end fuzz and race test.

Fix a race exposed by the above.

Change-Id: Ifaa39a90cefbde8d4c29bda197cc92592ded21bb
2014-11-25 17:09:17 +01:00
Bjoern Rabenstein d215e013b7 Fix the weird chunkDesc shuffling bug.
The root cause was that after chunkDesc eviction, the offset between
memory representation of chunk layout (via chunkDescs in memory) was
shiftet against chunks as layed out on disk. Keeping the offset up to
date is by no means trivial, so this commit is pretty involved.

Also, found a race that for some reason didn't bite us so far:
Persisting chunks was completel unlocked, so if chunks were purged on
disk at the same time, disaster would strike. However, locking the
persisting of chunk revealed interesting dead locks. Basically, never
queue under the fp lock.

Change-Id: I1ea9e4e71024cabbc1f9601b28e74db0c5c55db8
2014-11-25 17:09:17 +01:00
Bjoern Rabenstein f1de5b0c4e Run checkpointing of in-memory metrics and head chunks periodically.
Checkpointing interval is now a command line flag.

Along the way, several things were refactored.
- Restructure the way the storage is started and stopped..
- Number of series in checkpoint is now a uint64, not a varint.
  (Breaks old checkpoints, needs wipe!)
- More consistent naming and order of methods.

Change-Id: I883d9170c9a608ee716bb0ab3d0ded8ca03760d9
2014-11-25 17:09:04 +01:00
Bjoern Rabenstein 74c9b34a5e Improve storage instrumentation even more.
Add gauge for chunks and chunkdescs in memory (backed by a global
variable to be used later not only for instrumentation but also for
memory management).

Refactored instrumentation code once more (instrumentation.go is back :).

Change-Id: Ife39947e22a48cac4982db7369c231947f446e17
2014-11-25 17:09:04 +01:00
Bjoern Rabenstein 443dd33805 Improve instrumentation in storage.
Also, fix some other minor bugs.

Change-Id: If72f1c058b0f47d3e378fdf80228d7e9a8db06c7
2014-11-25 17:09:04 +01:00
Bjoern Rabenstein 1936a40e75 Minor loging improvement.
Change-Id: I7875d1a58ef9c5ff149f18e36f65959a4712fea2
2014-11-25 17:09:04 +01:00
Bjoern Rabenstein 096fa0f8b2 Squash a number of TODOs.
- Staleness delta is no a proper function parameter and not replicated
  from package ast.

- Named type 'chunks' replaced by explicit '[]chunk' to avoid confusion.

- For the same reason, replaced 'chunkDescs' by '[]*chunkDescs'.

- Verified that math.Modf is not a speed enhancement over conversion
  (actually 5x slower).

- Renamed firstTimeField, lastTimeField into chunkFirstTime and
  chunkLastTime.

- Verified unpin() is sufficiently goroutine-safe.

- Decided not to update archivedFingerprintToTimeRange upon series
  truncation and added a rationale why.

Change-Id: I863b8d785e5ad9f71eb63e229845eacf1bed8534
2014-11-25 17:09:04 +01:00
Bjoern Rabenstein 427c8d53a5 Fix handling of empty chunkDescs while preloading chunks.
Change-Id: I73ce89fe0ef90c6eda78218e5be2cbfa0207c364
2014-11-25 17:09:04 +01:00
Bjoern Rabenstein ecee5d8281 Fix head chunk persisting and a chunkDesc race condition.
- Head chunk persisting only happens in evictOlderThan, so do it
  there.  (With the previous code, it would never happen.)

- Raw accesses to chunkDesc.chunk are now done via isEvicted (with
  locking).

Change-Id: I48b07b56dfea4899b50df159b4ea566954396fcd
2014-11-25 17:09:04 +01:00
Bjoern Rabenstein 2b4ff620aa Return a nop iterator for series that have been purged completely.
Change-Id: I6e92cac4472486feefdecba8593c17867e8c710d
2014-11-25 17:09:03 +01:00
Julius Volz bfa64248b7 Deal with missing series in preloading.
Change-Id: Ibf3a57b329f40a3d5e0b98464a2f45d2f1bd07bf
2014-11-25 17:09:03 +01:00
Bjoern Rabenstein b3ed9aa7a2 Clean up start-up and shut-down.
Change-Id: Idff4bbb0a15a9f879bfbb3da5b1025179cab5e2c
2014-11-25 17:08:45 +01:00
Bjoern Rabenstein 4447708c9f Fix a race in target.go.
Also, fix problems in shutdown.
Starting serving and shutdown still has to be cleaned up properly.
It's a mess.

Change-Id: I51061db12064e434066446e6fceac32741c4f84c
2014-11-25 17:08:45 +01:00
Bjoern Rabenstein 38fc24d0ed Fix targetpool_test.go and other tests.
Change-Id: I91a4dd1d39e01f174e1aaae653ce1ed7aecaa624
2014-11-25 17:08:26 +01:00
Julius Volz 7f5d3c2c29 Fix and improve the fp locker.
Benchmark:
$ go test -bench 'Fingerprint' -test.run 'Fingerprint' -test.cpu=1,2,4

OLD
BenchmarkFingerprintLockerParallel        500000              3618 ns/op
BenchmarkFingerprintLockerParallel-2      100000             12257 ns/op
BenchmarkFingerprintLockerParallel-4      500000             10164 ns/op
BenchmarkFingerprintLockerSerial        10000000               283 ns/op
BenchmarkFingerprintLockerSerial-2      10000000               284 ns/op
BenchmarkFingerprintLockerSerial-4      10000000               288 ns/op

NEW
BenchmarkFingerprintLockerParallel       1000000              1018 ns/op
BenchmarkFingerprintLockerParallel-2     1000000              1164 ns/op
BenchmarkFingerprintLockerParallel-4     2000000               910 ns/op
BenchmarkFingerprintLockerSerial        50000000                56.0 ns/op
BenchmarkFingerprintLockerSerial-2      50000000                47.9 ns/op
BenchmarkFingerprintLockerSerial-4      50000000                54.5 ns/op

Change-Id: I3c65a43822840e7e64c3c3cfe759e1de51272581
2014-11-25 17:07:45 +01:00
Bjoern Rabenstein 8fba3302bc Bold changes to concurrency.
(WIP. Probably doesn't work yet.)

Change-Id: Id1537dfcca53831a1d428078a5863ece7bdf4875
2014-11-25 17:07:45 +01:00
Bjoern Rabenstein fcdf5a8ee7 Fix bugs in chunk evict code.
Also, simplify code by re-looking up metric in metric map.

Change-Id: Ib2092f9184374e5a543e87d3a9f4a74fda64b193
2014-11-25 17:07:45 +01:00
Bjoern Rabenstein 7e6a03fbf9 Fix a few concurrency issues before starting to use the new fp locker.
Change-Id: I8615e8816e79ef0882e123163ee590c739b79d12
2014-11-25 17:07:45 +01:00
Julius Volz db92620163 Instrument eviction and purge durations.
Change-Id: Ia5b2319363ad2644674c9b7a94162a89bcc296fb
2014-11-25 17:07:45 +01:00
Bjoern Rabenstein 01dd618a20 Fix a locking bug.
Change-Id: I183780785991d0b4165ce9186f53eb8201fb3ed5
2014-11-25 17:07:44 +01:00
Bjoern Rabenstein aea32b0b4b Avoid redundant fingerprint calculation.
Change-Id: Ief8a165dcfa5030226953346ec9dfe4a7787df1f
2014-11-25 17:07:44 +01:00
Bjoern Rabenstein e9ff29c547 Comment/code cleanup.
Change-Id: I38736e3d0fec79759a2bafa35aecf914480ff810
2014-11-25 17:07:44 +01:00
Bjoern Rabenstein c7aad110fb Add an indexing queue and batch the ops.
Some other improvements on the way, in particular codec -> codable
renaming and addition of LookupSet methods.

Change-Id: I978f8f3f84ca8e4d39a9d9f152ae0ad274bbf4e2
2014-11-25 17:07:44 +01:00
Bjoern Rabenstein 71206dbc06 More code cleanups.
Add license text everywhere.
And others....

Change-Id: I11ccde267a2ef7eb366c4788ba7aeae14ba7545c
2014-11-25 17:07:44 +01:00
Julius Volz f0d5d4bda3 Fix bug around index purging.
Change-Id: I8cea00e03f72bbeead2cbd2d26b34d986059ced0
2014-11-25 17:07:44 +01:00
Julius Volz 630b5a087a Also consider on-disk fingerprints during purge.
This reintroduces LevelDB iterators so that we can iterate through all
the on-disk fingerprints.

Change-Id: I007ee4638d038d2a4461bbda27f30fcaad411474
2014-11-25 17:07:35 +01:00
Bjoern Rabenstein f5f9f3514a Major code cleanup.
- Make it go-vet and golint clean.
- Add comments, TODOs, etc.

Change-Id: If1392d96f3d5b4cdde597b10c8dff1769fcfabe2
2014-11-25 17:02:53 +01:00
Bjoern Rabenstein 3592dc2359 Implement series eviction.
Change-Id: I7a503e0ba78aae3761d032851b06f2807122b085
2014-11-25 17:02:52 +01:00
Bjoern Rabenstein bbf49200ab Implement methods in persistence.go.
Change-Id: I804cdd0b30420e171825fd86fe1281eca0d5e638
2014-11-25 17:02:23 +01:00
Bjoern Rabenstein 5a128a04a9 Major reorganization of the storage.
Most important, the heads file will now persist all the chunk descs,
too. Implicitly, it will serve as the persisted form of the
fp-to-series map.

Change-Id: Ic867e78f2714d54c3b5733939cc5aef43f7bd08d
2014-11-25 17:02:01 +01:00
Bjoern Rabenstein 4770cf76a4 Make index package more self-contained.
Moved interna from diskPersistence into the indexer.
TotalIndexer now called diskIndexer.

Change-Id: I6c8c62cb171f12bbd8a5474773af7786d71ba388
2014-11-25 17:02:01 +01:00
Bjoern Rabenstein af77d5ef0b Added a few missing implementations in index.go.
Also, added closing of persistence and mem storage.

Change-Id: Iacf0d22c3520dd2584d9546984c1f8a5ed6cd54e
2014-11-25 17:02:01 +01:00
Julius Volz cca7ebe906 Some more cleanups / obsolete code removals.
Change-Id: I584144ceeeedafdb114266d8a6d2513e67b1d010
2014-11-25 17:02:00 +01:00
Julius Volz 7e85711df0 Beginnings of a tiered index implementation.
This reintroduces a LevelDB-based metrics index.

Change-Id: I4111540301c52255a07b2f570761707a32f72c05
2014-11-25 17:02:00 +01:00
Bjoern Rabenstein ecdf5ab14f Index-persistence switched from gob to a hand-coded solution.
Change-Id: Ib4ec42535bd08df16d34d4774bb638e35c5a1841
2014-11-25 17:02:00 +01:00
Julius Volz e7ed39c9a6 Initial experimental snapshot of next-gen storage.
Change-Id: Ifb8709960dbedd1d9f5efd88cdd359ee9fa9d26d
2014-11-25 17:02:00 +01:00