Commit graph

108 commits

Author SHA1 Message Date
Julius Volz 044ebce779 Review fixups. 2016-09-28 23:42:44 +02:00
Julius Volz ab80ced756 storage: separate chunk package, publish more names
This is a followup to https://github.com/prometheus/prometheus/pull/2011.

This publishes more of the methods and other names of the chunk code and
moves the chunk code to its own package. There's some unavoidable
ugliness: the chunk and chunkDesc metrics are used by both packages, so
I had to move them to the chunk package. That isn't great, but I don't
see how to do it better without a larger redesign of everything. Same
for the evict requests and some other types.
2016-09-26 13:25:11 +02:00
Matthew Campbell 67d76e3a5d timeseries: store varbit encoded data into cassandra 2016-09-21 17:56:55 +02:00
Matt Bostock e618af5d0b Storage: Add crash recovery metric 'started_dirty'
...to indicate when crash recovery was invoked during Prometheus
startup.

Fixes #1918.
2016-08-27 21:41:06 +02:00
Julius Volz 3bfec97d46 Make the storage interface higher-level.
See discussion in
https://groups.google.com/forum/#!topic/prometheus-developers/bkuGbVlvQ9g

The main idea is that the user of a storage shouldn't have to deal with
fingerprints anymore, and should not need to do an individual preload
call for each metric. The storage interface needs to be made more
high-level to not expose these details.

This also makes it easier to reuse the same storage interface for remote
storages later, as fewer roundtrips are required and the fingerprint
concept doesn't work well across the network.

NOTE: this deliberately gets rid of a small optimization in the old
query Analyzer, where we dedupe instants and ranges for the same series.
This should have a minor impact, as most queries do not have multiple
selectors loading the same series (and at the same offset).
2016-07-25 13:59:22 +02:00
beorn7 064b57858e Consistently use the Seconds() method for conversion of durations
This also fixes one remaining case of recording integral numbers
of seconds only for a metric, i.e. this will probably fix #1796.
2016-07-07 15:24:35 +02:00
Fabian Reinartz 425736a377 *: remove last remainers of non-second metrics 2016-06-23 17:50:39 +02:00
Jan van Valburg 68f3df49d0 stoarge: fix 'access denied' error on Windows
On Windows, it is not possible to rename or delete a file that is
currerntly open. This change closes the file in dropAndPersistChunks
before it tries to delete it, or rename the temporary file to it.
2016-06-21 11:21:20 +02:00
beorn7 a90d645378 Checkpoint fingerprint mappings only upon shutdown
Before, we checkpointed after every newly detected fingerprint
collision, which is not a problem as long as collisions are
rare. However, with a sufficient number of metrics or particular
nature of the data set, there might be a lot of collisions, all to be
detected upon the first set of scrapes, and then the checkpointing
after each detection will take a quite long time (it's O(n²),
essentially).

Since we are rebuilding the fingerprint mapping during crash recovery,
the previous, very conservative approach didn't even buy us
anything. We only ever read from the checkpoint file after a clean
shutdown, so the only time we need to write the checkpoint file is
during a clean shutdown.
2016-04-15 01:03:28 +02:00
beorn7 47e3c90f9b Clean up error propagation
Only return an error where callers are doing something with it except
simply logging and ignoring.

All the errors touched in this commit flag the storage as dirty
anyway, and that fact is logged anyway. So most of what is being
removed here is just log spam.

As discussed earlier, the class of errors that flags the storage as
dirty signals fundamental corruption, no even bubbling up a one-time
warning to the user (e.g. about incomplete results) isn't helping much
because _anything_ happening in the storage has to be doubted from
that point on (and in fact retroactively into the past, too). Flagging
the storage dirty, and alerting on it (plus marking the state in the
web UI) is the only way I can see right now.

As a byproduct, I cleaned up the setDirty method a bit and improved
the logged errors.
2016-03-09 18:56:30 +01:00
beorn7 836f1db04c Improve MetricsForLabelMatchers
WIP: This needs more tests.

It now gets a from and through value, which it may opportunistically
use to optimize the retrieval. With possible future range indices,
this could be used in a very efficient way. This change merely applies
some easy checks, which should nevertheless solve the use case of
heavy rule evaluations on servers with a lot of series churn.

Idea is the following:

- Only archive series that are at least as old as the headChunkTimeout
  (which was already extremely unlikely to happen).

- Then maintain a high watermark for the last archival, i.e. no
  archived series has a sample more recent than that watermark.

- Any query that doesn't reach to a time before that watermark doesn't
  have to touch the archive index at all. (A production server at
  Soundcloud with the aforementioned series churn and heavy rule
  evaluations spends 50% of its CPU time in archive index
  lookups. Since rule evaluations usually only touch very recent
  values, most of those lookup should disappear with this change.)

- Federation with a very broad label matcher will profit from this,
  too.

As a byproduct, the un-needed MetricForFingerprint method was removed
from the Storage interface.
2016-03-09 00:25:59 +01:00
beorn7 01795382c9 Merge branch 'beorn7/storage4' into beorn7/storage5 2016-03-08 00:20:13 +01:00
beorn7 f7fc542db6 Merge branch 'master' into beorn7/storage4
Conflicts:
	storage/local/persistence.go
2016-03-08 00:14:00 +01:00
beorn7 f193f2b8ef Add a command to promtool that dumps metadata of heads.db
I needed this today for debugging. It can certainly be improved, but
it's already quite helpful.

I refactored the reading of heads.db files out of persistence, which
is an improvement, too.

I made minor changes to the cli package to allow outputting via the
io.Writer interface.
2016-03-07 16:21:57 +01:00
beorn7 fc7de5374a Quarantine series upon problem writing to the series file
This fixes https://github.com/prometheus/prometheus/issues/1059 , but
not in the obvious way (simply not updating the persist watermark,
because that's actually not that simple - we don't really know what
has gone wrong exactly). As any errors relevant here are most likely
caused by severe and unrecoverable problems with the series file,
Using the now quarantine feature is the right step. We don't really
have to be worried about any inconsistent state of the series because
it will be removed for good ASAP. Another plus is that we don't have
to declare the whole storage dirty anymore.
2016-03-03 13:15:02 +01:00
beorn7 0ea5801e47 Handle errors caused by data corruption more gracefully
This requires all the panic calls upon unexpected data to be converted
into errors returned. This pollute the function signatures quite
lot. Well, this is Go...

The ideas behind this are the following:

- panic only if it's a programming error. Data corruptions happen, and
  they are not programming errors.

- If we detect a data corruption, we "quarantine" the series,
  essentially removing it from the database and putting its data into
  a separate directory for forensics.

- Failure during writing to a series file is not considered corruption
  automatically. It will call setDirty, though, so that a
  crashrecovery upon the next restart will commence and check for
  that.

- Series quarantining and setDirty calls are logged and counted in
  metrics, but are hidden from the user of the interfaces in
  interface.go, whith the notable exception of Append(). The reasoning
  is that we treat corruption by removing the corrupted series, i.e. a
  query for it will return no results on its next call anyway, so
  return no results right now. In the case of Append(), we want to
  tell the user that no data has been appended, though.

Minor side effects:

- Now consistently using filepath.* instead of path.*.

- Introduced structured logging where I touched it. This makes things
  less consistent, but a complete change to structured logging would
  be out of scope for this PR.
2016-03-02 23:02:34 +01:00
beorn7 28e9bbc15f Populate chunkDesc.chunkLastTime during checkpoint loading, too 2016-02-24 13:58:34 +01:00
beorn7 ef3ab96111 Populate first and last time in the chunk descriptor earlier
The First time is kind of trivial as we always know it when we create
a new chunkDesc.

The last time is only know when the chunk is closed, so we have to set
it at that time.

The change saves a lot of digging down into the chunk
itself. Especially the last time is relative expensive as it involves
the creation of an iterator. The first time access now doesn't require
locking, which is also a nice gain.
2016-02-15 14:06:09 +01:00
beorn7 a2cd479058 Fix calculation of chunks to persist after restart
Since we are not overestimating the number of chunks to persist
anymore, this commit also adjusts the default value for
-storage.local.memory-chunks. Update of documentation will follow.
2016-01-25 19:33:51 +01:00
beorn7 14796bdb60 Improve chunkMaxBatchSize doc comment 2016-01-25 18:57:51 +01:00
beorn7 582af1618c Streamline chunk writing
This helps to avoid allocations in the same way we were already doing
it during reading.
2016-01-25 16:36:36 +01:00
beorn7 add2ebdd56 Tolerate the lost+found directory in the data directory 2016-01-11 18:05:36 +01:00
beorn7 4221c7de5c Improve handling of series file truncation
If only very few chunks are to be truncated from a very large series
file, the rewrite of the file is a lorge overhead. With this change, a
certain ratio of the file has to be dropped to make it happen. While
only causing disk overhead at about the same ratio (by default 10%),
it will cut down I/O by a lot in above scenario.
2016-01-11 16:42:10 +01:00
Fabian Reinartz e3b6ec9784 Switch to common/log 2015-10-03 10:21:43 +02:00
Julius Volz af513468eb Fix some dead code, missing error checks, shadowings.
I applied
https://medium.com/@jgautheron/quality-pipeline-for-go-projects-497e34d6567
and was greeted with a deluge of warnings, most of which were not
applicable or really fixable realistically. These are some of the first
ones I decided to fix.
2015-09-14 12:21:34 +02:00
beorn7 daeccdd0e9 Fix DropMetricsForFingerprints
It now deletes the series file also for archived series.

Also, fix a naming error in a doc comment.
2015-09-11 15:47:23 +02:00
Julius Volz 6774a73878 Fix error checking and logging around checkpointing. 2015-09-07 19:34:59 +02:00
Fabian Reinartz c9d396f476 Replace metric.LabelPair with model.LabelPair 2015-08-22 13:32:13 +02:00
Fabian Reinartz 438e232c9b Fix grouping of import blocks 2015-08-22 09:42:45 +02:00
Fabian Reinartz 306e8468a0 Switch from client_golang/model to common/model 2015-08-21 13:33:38 +02:00
beorn7 699946bf32 Fix chunk desc loading.
If all samples in consecutive chunks have the same timestamp, the way
we used to load chunks will fail. With this change, the persist
watermark is used to load the right amount of chunkDescs from disk.

This bug is a possible reason for the rare storage corruption we have
observed.
2015-07-16 13:09:20 +02:00
beorn7 ff08f0b6fe storage: ensure timestamp monotonicity within series.
Fixes https://github.com/prometheus/prometheus/issues/481

While doing so, clean up and fix a few other things:

- Fix `go vet` warnings (@fabxc to blame ;).

- Fix a racey problem with unarchiving: Whenever we unarchive a
  series, we essentially want to do something with it. However, until
  we have done something with it, it appears like a series that is
  ready to be archived or even purged. So e.g. it would be ignored
  during checkpointing. With this fix, we always load the chunkDescs
  upon unarchiving. This is wasteful if we only want to add a new
  sample to an archived time series, but the (presumably more common)
  case where we access an archived time series in a query doesn't
  become more expensive.

- The change above streamlined the getOrCreateSeries ond
  newMemorySeries flow. Also, the modTime is now always set correctly.

- Fix the leveldb-backed implementation of KeyValueStore.Delete. It
  had the wrong behavior of still returning true, nil if a
  non-existing key has been passed in.
2015-07-15 18:56:53 +02:00
beorn7 9016917d1c Increment dirty counter only if setDirty(true) is called.
Currently, we increment the counter even if setDirty(false) is called,
which sets the storage clean.
2015-06-22 18:12:55 +02:00
Fabian Reinartz 0de6edbdfc Move pkg/ to util/ 2015-06-01 21:12:32 +02:00
Fabian Reinartz 2317b001d0 Move flock package to pkg/flock 2015-06-01 21:12:31 +02:00
beorn7 3b9ab546e6 Add metrics to count inconsistencies and fp collisions. 2015-05-21 18:46:20 +02:00
Björn Rabenstein c44e7cd105 Merge pull request #706 from prometheus/beorn7/persistence2
Improve iterator performance.
2015-05-21 13:48:52 +02:00
beorn7 3b9c421a69 Weed out all the [Gg]et* method names.
The only exception is getNumChunksToPersist to avoid naming the struct
member numChunksToPersist in a weird way.
2015-05-20 19:13:06 +02:00
Julius Volz 267fd34156 Switch Prometheus to use github.com/prometheus/log.
This change is conceptually very simple, although the diff is large. It
switches logging from "github.com/golang/glog" to
"github.com/prometheus/log", while not actually changing any log
messages. V(1)-style logging has been changed to be log.Debug*().
2015-05-20 18:19:32 +02:00
beorn7 cd5574bf8a Make chunk and series iterators more efficient. 2015-05-20 16:19:34 +02:00
Fabian Reinartz d8440d75f1 Do not start storage processing before Start() is called. 2015-05-19 13:51:45 +02:00
beorn7 c36e0e05f1 Add crash recovery of fingerprint mappings. 2015-05-07 18:58:14 +02:00
beorn7 2235cec175 Handle fingerprint collisions. 2015-05-07 18:17:59 +02:00
beorn7 a052d32609 Comment improvement. 2015-04-14 10:49:43 +02:00
beorn7 66fc61f9b7 Make bufPool a member of the persistence struct. 2015-04-14 10:43:09 +02:00
beorn7 b02d900e61 Improve chunk and chunkDesc loading.
Also, clean up some things in the code (especially introduction of the
chunkLenWithHeader constant to avoid the same expression all over the place).

Benchmark results:

BEFORE
BenchmarkLoadChunksSequentially     5000            283580 ns/op          152143 B/op        312 allocs/op
BenchmarkLoadChunksRandomly        20000             82936 ns/op           39310 B/op         99 allocs/op
BenchmarkLoadChunkDescs            10000            110833 ns/op           15092 B/op        345 allocs/op

AFTER
BenchmarkLoadChunksSequentially    10000            146785 ns/op          152285 B/op        315 allocs/op
BenchmarkLoadChunksRandomly        20000             67598 ns/op           39438 B/op        103 allocs/op
BenchmarkLoadChunkDescs            20000             99631 ns/op           12636 B/op        192 allocs/op

Note that everything is obviously loaded from the page cache (as the
benchmark runs thousands of times with very small series files). In a
real-world scenario, I expect a larger impact, as the disk operations
will more often actually hit the disk. To load ~50 sequential chunks,
this reduces the iops from 100 seeks and 100 reads to 1 seek and 1
read.
2015-04-13 21:06:04 +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