Commit Graph

235 Commits (22890b1eb3eafb64a8fc37aa39e05aad1c10a676)

Author SHA1 Message Date
Jesus Vazquez 5c3f058755 Add unit test and also protect truncateOOO
Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>
2023-02-10 15:18:17 +01:00
Justin Lei af1d9e01c7
Refactor tsdbutil for tests/native histograms (#11948)
* Add float histograms to ChunkFromSamplesGeneric

Signed-off-by: Justin Lei <justin.lei@grafana.com>

* Add Generate*Samples functions to tsdbutil

Signed-off-by: Justin Lei <justin.lei@grafana.com>

* PR responses

Signed-off-by: Justin Lei <justin.lei@grafana.com>

---------

Signed-off-by: Justin Lei <justin.lei@grafana.com>
2023-02-10 17:09:33 +05:30
George Krajcsovits 1f0cc09579
Export single ith test histogram generation functions (#11911)
* Export single ith test histogram generation functions

Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>

* Do not set counter reset hint for non-gauge histograms individually

Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>

* Apply suggestions from code review

Co-authored-by: Ganesh Vernekar <ganeshvern@gmail.com>
Signed-off-by: George Krajcsovits <krajorama@users.noreply.github.com>

---------

Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>
Signed-off-by: George Krajcsovits <krajorama@users.noreply.github.com>
Co-authored-by: Ganesh Vernekar <ganeshvern@gmail.com>
2023-02-01 16:23:38 +05:30
beorn7 1cfc8f65a3 histograms: Return actually useful counter reset hints
This is a bit more conservative than we could be. As long as a chunk
isn't the first in a block, we can be pretty sure that the previous
chunk won't disappear. However, the incremental gain of returning
NotCounterReset in these cases is probably very small and might not be
worth the code complications.

Wwith this, we now also pay attention to an explicitly set counter
reset during ingestion. While the case doesn't show up in practice
yet, there could be scenarios where the metric source knows there was
a counter reset even if it might not be visible from the values in the
histogram. It is also useful for testing.

Signed-off-by: beorn7 <beorn@grafana.com>
2023-01-25 16:57:21 +01:00
Ganesh Vernekar cb2be6e62f
Merge pull request #11779 from codesome/memseries-ooo
tsdb: Only initialise out-of-order fields when required
2023-01-16 10:58:05 +05:30
Ganesh Vernekar 38fa151a7c
tsdb: Only initialise out-of-order fields when required
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2023-01-12 20:29:16 +05:30
beorn7 6dcd03dbf3 tsdb: Add integer gauge histogram support
This follows what #11783 has done for float gauge histograms.

Signed-off-by: beorn7 <beorn@grafana.com>
2023-01-11 13:28:43 +01:00
Ganesh Vernekar 57bcbf1888
Merge pull request #11783 from codesome/gauge-histogram
tsdb: Add gauge histogram support
2023-01-10 19:06:08 +05:30
Ganesh Vernekar 3c2ea91a83
tsdb: Test gauge float histograms
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2023-01-10 18:35:37 +05:30
Ganesh Vernekar c94a41c4b2
Merge pull request #11785 from Fish-pro/erroris
Use errors.Is to check for a specific error
2023-01-10 14:56:14 +05:30
Fish-pro 6ed71a229e Use errors.Is to check for a specific error
Signed-off-by: Fish-pro <zechun.chen@daocloud.io>
2022-12-29 23:23:07 +08:00
Ganesh Vernekar e555469ba1
tsdb: Remove isHistogramSeries from memSeries
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-12-28 14:31:55 +05:30
Marc Tudurí 9474610baf
Support FloatHistogram in TSDB (#11522)
Extends Appender.AppendHistogram function to accept the FloatHistogram. TSDB supports appending, querying, WAL replay, for this new type of histogram.

Signed-off-by: Marc Tudurí <marctc@protonmail.com>
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
Co-authored-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-12-28 14:25:07 +05:30
Julien Pivotto 739494d81b
Fix alignment of atomic int64 (#11547)
* Fix atomix int64 placement
* Test main for 386

Signed-off-by: Julien Pivotto <roidelapluie@o11y.eu>
2022-11-09 11:18:49 +01:00
Ganesh Vernekar 648be89822
Merge remote-tracking branch 'upstream/main' into fix-conflict
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-10-12 14:20:02 +05:30
Signed-off-by: Jesus Vazquez 3362bf6d79
Fix merge conflicts
Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
Co-authored-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-10-11 22:53:37 +05:30
Jesus Vazquez 775d90d5f8
TSDB: Rename wal package to wlog (#11352)
The wlog.WL type can now be used to create a Write Ahead Log or a Write
Behind Log.

Before the prefix for wbl metrics was
'prometheus_tsdb_out_of_order_wal_' and has been replaced with
'prometheus_tsdb_out_of_order_wbl_'.

Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>
Signed-off-by: Jesus Vazquez <jesusvazquez@users.noreply.github.com>
Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
2022-10-10 20:38:46 +05:30
Jesus Vazquez e934d0f011 Merge 'main' into sparsehistogram
Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>
2022-10-05 22:14:49 +02:00
Ganesh Vernekar d0a6488c74
Update metrics for histograms
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-10-03 13:48:59 +05:30
Bryan Boreham d166da7b59
tsdb: stop saving a copy of last 4 samples in memSeries (#11296)
* TSDB chunks: remove race between writing and reading

Because the data is stored as a bit-stream, the last byte in the stream
could change if the stream is appended to after an Iterator is obtained.
Copy the last byte when the Iterator is created, so we don't have to
read it later.

Clarify in comments that concurrent Iterator and Appender are allowed,
but the chunk must not be modified while an Iterator is created.
(This was already the case, in order to copy the bstream slice header.)

* TSDB: stop saving last 4 samples in memSeries

This extra copy of the last 4 samples was introduced to avoid a race
condition between reading the last byte of the chunk and writing to it.

But now we have fixed that by having `bstreamReader` copy the last byte,
we don't need to copy the last 4 samples.

This change saves 56 bytes per series, which is very worthwhile when
you have millions or tens of millions of series.

* TSDB: tidy up stopIterator re-use

Previous changes have left this code duplicating some lines; pull
them out to a separate function and tidy up.

* TSDB head_test: stop checking when iterators are wrapped

The behaviour has changed so chunk iterators are only wrapped when
transaction isolation requires them to stop short of the end.
This makes tests fail which are checking the type.

Tests should check the observable behaviour, not the type.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
Co-authored-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-09-27 19:32:05 +05:30
Bryan Boreham ff00dee262
tsdb: turn off transaction isolation for head compaction (#11317)
* tsdb: add a basic test for read/write isolation

* tsdb: store the min time with isolationAppender
So that we can see when appending has moved past a certain point in time.

* tsdb: allow RangeHead to have isolation disabled
This will be used when for head compaction.

* tsdb: do head compaction with isolation disabled
This saves a lot of work tracking appends done while compaction is ongoing.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-09-27 19:31:23 +05:30
Bryan Boreham d0607435a2
tsdb: remove chunkRange and oooCapMax from memSeries (#11288)
* tsdb: remove chunkRange from memSeries

chunkRange is the (oddly-named) configured duration for the head block.

We don't need a copy of this value per series. Pass it down where
required, and remove the copy.

The value in `Head` is only updated in `resetInMemoryState()`, which
also discards all `memSeries`.

* tsdb: remove oooCapMax from memSeries

oooCapMax is the configured maximum capacity for an out-of-order chunk.

Storing it per-series uses extra memory, and has surprising behaviour
if users change the value in config - series created before the change
will keep their old value.

Instead, pass it down where required, and remove the per-series value.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
Co-authored-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-09-27 13:52:22 +05:30
Jesus Vazquez c1b669bf9b
Add out-of-order sample support to the TSDB (#11075)
* Introduce out-of-order TSDB support

This implementation is based on this design doc:
https://docs.google.com/document/d/1Kppm7qL9C-BJB1j6yb6-9ObG3AbdZnFUBYPNNWwDBYM/edit?usp=sharing

This commit adds support to accept out-of-order ("OOO") sample into the TSDB
up to a configurable time allowance. If OOO is enabled, overlapping querying
are automatically enabled.

Most of the additions have been borrowed from
https://github.com/grafana/mimir-prometheus/
Here is the list ist of the original commits cherry picked
from mimir-prometheus into this branch:
- 4b2198d7ec
- 2836e5513f
- 00b379c3a5
- ff0dc75758
- a632c73352
- c6f3d4ab33
- 5e8406a1d4
- abde1e0ba1
- e70e769889
- df59320886

Co-authored-by: Jesus Vazquez <jesus.vazquez@grafana.com>
Co-authored-by: Ganesh Vernekar <ganeshvern@gmail.com>
Co-authored-by: Dieter Plaetinck <dieter@grafana.com>
Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>

* gofumpt files

Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>

* Add license header to missing files

Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>

* Fix OOO tests due to existing chunk disk mapper implementation

Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>

* Fix truncate int overflow

Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>

* Add Sync method to the WAL and update tests

Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>

* remove useless sync

Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>

* Update minOOOTime after truncating Head

* Update minOOOTime after truncating Head

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix lint

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Add a unit test

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>

* Load OutOfOrderTimeWindow only once per appender

Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>

* Fix OOO Head LabelValues and PostingsForMatchers

Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>

* Fix replay of OOO mmap chunks

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Remove unnecessary err check

Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>

* Prevent panic with ApplyConfig

Signed-off-by: Ganesh Vernekar 15064823+codesome@users.noreply.github.com
Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>

* Run OOO compaction after restart if there is OOO data from WBL

Signed-off-by: Ganesh Vernekar 15064823+codesome@users.noreply.github.com
Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>

* Apply Bartek's suggestions

Co-authored-by: Bartlomiej Plotka <bwplotka@gmail.com>
Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>

* Refactor OOO compaction

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Address comments and TODOs

- Added a comment explaining why we need the allow overlapping
  compaction toggle
- Clarified TSDBConfig OutOfOrderTimeWindow doc
- Added an owner to all the TODOs in the code

Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>

* Run go format

Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>

* Fix remaining review comments

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix tests

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Change wbl reference when truncating ooo in TestHeadMinOOOTimeUpdate

Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>

* Fix TestWBLAndMmapReplay test failure on windows

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Address most of the feedback

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Refactor the block meta for out of order

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix windows error

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix review comments

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
Signed-off-by: Ganesh Vernekar 15064823+codesome@users.noreply.github.com
Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
Co-authored-by: Ganesh Vernekar <ganeshvern@gmail.com>
Co-authored-by: Dieter Plaetinck <dieter@grafana.com>
Co-authored-by: Oleg Zaytsev <mail@olegzaytsev.com>
Co-authored-by: Bartlomiej Plotka <bwplotka@gmail.com>
2022-09-20 22:35:50 +05:30
Bryan Boreham d2701be53a
tsdb: remove chunk pool from memSeries (#11280)
The chunk pool belongs to the head not to the series. Pass it down where
required, and remove the copy of the pointer that `memSeries` was
holding.

`safeChunk` also needs to hold it, because in scenarios where it is used
we don't have a reference to the head. However it was already holding
`chunkDiskMapper` for the same reason, so no big change.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-09-15 13:22:09 +05:30
Ganesh Vernekar d354f20c2a
Add a feature flag to control native histogram ingestion (#11253)
* Add runtime config to control native histogram ingestion

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Make the config into a CLI flag

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-09-14 17:38:34 +05:30
Julien Pivotto ec6c1f17d1
Update dependencies (#11287)
Updating dependencies following CI changes and move to go 1.19

Signed-off-by: Julien Pivotto <roidelapluie@o11y.eu>
2022-09-09 13:28:55 +02:00
Łukasz Mierzwa 3196c98bc2
Reduce memSeries memory usage by decoupling metadata (#11152)
Metadata was added recently but doesn't seem to be used much, at least as far as I could identify.
Yet it's part of memSeries struct and so even when empty takes 48 bytes,
which is a lot given that without it memSeries requires 224 bytes.
This change turns it into a pointer on the struct, that get set only when metadata is actually set of given series.

Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>

Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
2022-08-17 15:32:28 +05:30
beorn7 c9fd3c235d Merge branch 'main' into sparsehistogram 2022-08-10 17:54:37 +02:00
Levi Harrison cb8582637a
Implement rollback for histograms (#11071)
Signed-off-by: Levi Harrison <git@leviharrison.dev>
2022-07-29 14:18:53 +05:30
Paschalis Tsilias d1122e0743
Introduce TSDB changes for appending metadata to the WAL (#10972)
* Append metadata to the WAL

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Remove extra whitespace; Reword some docstrings and comments

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Use RLock() for hasNewMetadata check

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Use single byte for metric type in RefMetadata

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Update proposed WAL format for single-byte type metadata

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Implementa MetadataAppender interface for the Agent

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Address first round of review comments

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Amend description of metadata in wal.md

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Correct key used to retrieve metadata from cache

When we're setting metadata entries in the scrapeCace, we're using the
p.Help(), p.Unit(), p.Type() helpers, which retrieve the series name and
use it as the cache key. When checking for cache entries though, we used
p.Series() as the key, which included the metric name _with_ its labels.
That meant that we were never actually hitting the cache. We're fixing
this by utiling the __name__ internal label for correctly getting the
cache entries after they've been set by setHelp(), setType() or
setUnit().

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Put feature behind a feature flag

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Fix AppendMetadata docstring

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Reorder WAL format document

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Change error message of AppendMetadata; Fix access of s.meta in AppendMetadata

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Reuse temporary buffer in Metadata encoder

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Only keep latest metadata for each refID during checkpointing

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Fix test that's referencing decoding metadata

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Avoid creating metadata block if no new metadata are present

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Add tests for corrupt metadata block and relevant record type

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Fix CR comments

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Extract logic about changing metadata in an anonymous function

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Implement new proposed WAL format and amend relevant tests

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Use 'const' for metadata field names

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Apply metadata to head memSeries in Commit, not in AppendMetadata

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Add docstring and rename extracted helper in scrape.go

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Add tests for tsdb-related cases

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Fix linter issues vol1

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Fix linter issues vol2

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Fix Windows test by closing WAL reader files

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Use switch instead of two if statements in metadata decoding

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Fix review comments around TestMetadata* tests

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Add code for replaying WAL; test correctness of in-memory data after a replay

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Remove scrape-loop related code from PR

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Address first round of comments

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Simplify tests by sorting slices before comparison

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Fix test to use separate transactions

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Empty out buffer and record slices after encoding latest metadata

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Fix linting issue

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Update calculation for DroppedMetadata metric

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Rename MetadataAppender interface and AppendMetadata method to MetadataUpdater/UpdateMetadata

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Reuse buffer when encoding latest metadata for each series

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Fix review comments; Check all returned error values using two helpers

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Simplify use of helpers

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>

* Satisfy linter

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
2022-07-19 10:58:52 +02:00
beorn7 28f028e938 Merge branch 'main' into sparsehistogram 2022-07-12 19:07:13 +02:00
Xiaochao Dong (@damnever) 6b042da2d8 Fix panic if series is not found when deleting series
Signed-off-by: Xiaochao Dong (@damnever) <the.xcdong@gmail.com>
2022-06-24 15:55:32 +08:00
Steve Azzopardi 04fe2c9522
fix(tsdb): inc mmap corruption counter on mmap out of sequence error (#10406)
What
---
When we see out of sequence chunks increase the chunk corruption counter
to indicate that one of the chunks was corrupted.

Reference: https://github.com/prometheus/prometheus/pull/10406#issuecomment-1142595527
Signed-off-by: Steve Azzopardi <steveazz@outlook.com>
2022-06-22 14:03:12 +05:30
beorn7 4210aac74a Merge branch 'main' into sparsehistogram 2022-03-22 14:47:42 +01:00
Ganesh Vernekar 4cc25c0cb0
Fix panic on query when m-map replay fails with snapshot enabled (#10348)
* Fix panic on query when m-map replay fails with snapshot enabled

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix review

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix flake

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-02-25 08:53:40 -07:00
Ganesh Vernekar 24827782cb
Fix panics when m-mapping head chunks (#10316)
* Fix panics when m-mapping head chunks

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix review comments

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix reviews

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-02-22 20:35:15 +05:30
Mauro Stettler 0df3489275
Write chunks via queue, predicting the refs (#10051)
* Write chunks via queue, predicting the refs

Our load tests have shown that there is a latency spike in the
remote write handler whenever the head chunks need to be written,
because chunkDiskMapper.WriteChunk() blocks until the chunks are written
to disk.

This adds a queue to the chunk disk mapper which makes the WriteChunk()
method non-blocking unless the queue is full. Reads can still be served
from the queue.

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* address PR feeddback

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* initialize metrics without .Add(0)

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* change isRunningMtx to normal lock

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* do not re-initialize chunkrefmap

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* update metric outside of lock scope

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* add benchmark for adding job to chunk write queue

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* remove unnecessary "success" var

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* gofumpt -extra

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* avoid WithLabelValues call in addJob

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* format comments

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* addressing PR feedback

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* rename cutExpectRef to cutAndExpectRef

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* use head.Init() instead of .initTime()

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* address PR feedback

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* PR feedback

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* update test according to PR feedback

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* replace callbackWg -> awaitCb

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* better test of truncation with empty files

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* replace callbackWg -> awaitCb

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
2022-01-10 13:36:45 +00:00
beorn7 6f33ab2b35 Merge branch 'main' into sparsehistogram 2021-12-15 13:49:33 +01:00
Ganesh Vernekar 05d4d97bcd
Fix queries after a failed snapshot replay (#9980)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-12-08 15:32:14 +00:00
Nick Pillitteri 084bd70708
Convert atomic Int64 to native type when logging value (#9938)
The atomic Int64 type wasn't able to be represented when logging
via go-kit log and ended up as `"unsupported value type"`.

Signed-off-by: Nick Pillitteri <nick.pillitteri@grafana.com>
2021-12-06 22:25:22 +01:00
beorn7 e4e24453fa Merge branch 'main' into beorn7/merge2 2021-11-30 17:19:06 +01:00
Björn Rabenstein 7e42acd3b1
tsdb: Rework iterators (#9877)
- Pick At... method via return value of Next/Seek.
- Do not clobber returned buckets.
- Add partial FloatHistogram suppert.

Note that the promql package is now _only_ dealing with
FloatHistograms, following the idea that PromQL only knows float
values.

As a byproduct, I have removed the histogramSeries metric. In my
understanding, series can have both float and histogram samples, so
that metric doesn't make sense anymore.

As another byproduct, I have converged the sampleBuf and the
histogramSampleBuf in memSeries into one. The sample type stored in
the sampleBuf has been extended to also contain histograms even before
this commit.

Signed-off-by: beorn7 <beorn@grafana.com>
2021-11-29 13:24:23 +05:30
Ganesh Vernekar 26c0a433f5
Support appending different sample types to the same series (#9705)
* Support appending different sample types to the same series

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix comments

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix build

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-11-26 17:43:27 +05:30
Darshan Chaudhary 9dcf8b2208
Add the ability to disable tsdb isolation (#9270)
* Disable isolation in isolation struct

Signed-off-by: darshanime <deathbullet@gmail.com>

* Run tsdb tests with isolation disabled

Signed-off-by: darshanime <deathbullet@gmail.com>

* Check for isolation disabled in isoState.Close()

Signed-off-by: darshanime <deathbullet@gmail.com>

* use t.Skip to skip isolation tests when disabled

Signed-off-by: darshanime <deathbullet@gmail.com>

* address review comments

Signed-off-by: darshanime <deathbullet@gmail.com>

* fix test for defaultIsolationState

Signed-off-by: darshanime <deathbullet@gmail.com>

* Change flag name. Set flag in DB. Do not init txRing. Close isoState.

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Test disabled isolation in CircleCI test_go

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Skip isolation related tests in db_test.go

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

Co-authored-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-11-19 15:41:32 +05:30
beorn7 5d4db805ac Merge branch 'main' into sparsehistogram 2021-11-17 19:57:31 +01:00
Dieter Plaetinck 067efc3725
clarify HeadChunkID type and usage (#9726)
Signed-off-by: Dieter Plaetinck <dieter@grafana.com>
Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
2021-11-17 18:35:10 +05:30
Dieter Plaetinck 0fac9bb859
Add basic initial developer docs for TSDB (#9451)
* Add basic initial developer docs for TSDB

There's a decent amount of content already out there (blog posts,
conference talks, etc), but:
* when they get stale, they don't tend to get updated
* they still leave me with questions that I'ld like to answer
  for developers (like me) who want to use, or work with, TSDB

What I propose is developer docs inside the prometheus
repository.  Easy to find and harness the power of the community
to expand it and keep it up to date.

* perfect is the enemy of good.  Let's have a base and incrementally improve
* Markdown docs should be broad but not too deep.  Source code comments
  can complement them, and are the ideal place for implementation details.

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* use example code that works out of the box

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* Apply suggestions from code review

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* PR feedback

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* more docs

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* PR feedback

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* Apply suggestions from code review

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

Co-authored-by: Bartlomiej Plotka <bwplotka@gmail.com>

* Apply suggestions from code review

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

* feedback

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* Update tsdb/docs/usage.md

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

* final tweaks

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* workaround docs versioning issue

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* Move example code to real executable, testable example.

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* cleanup example test and make sure it always reproduces

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* obtain temp dir in a way that works with older Go versions

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* Fix Ganesh's comments

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
Co-authored-by: Bartlomiej Plotka <bwplotka@gmail.com>
Co-authored-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-11-17 15:51:27 +05:30
beorn7 4c28d9fac7 Move to histogram.Histogram pointers
This is to avoid copying the many fields of a histogram.Histogram all
the time.

This also fixes a bunch of formerly broken tests.

Signed-off-by: beorn7 <beorn@grafana.com>
2021-11-12 23:17:35 +01:00
beorn7 c954cd9d1d Move packages out of deprecated pkg directory
This creates a new `model` directory and moves all data-model related
packages over there:
  exemplar labels relabel rulefmt textparse timestamp value

All the others are more or less utilities and have been moved to `util`:
  gate logging modetimevfs pool runtime

Signed-off-by: beorn7 <beorn@grafana.com>
2021-11-09 08:03:10 +01:00
Dieter Plaetinck cda025b5b5
TSDB: demistify SeriesRefs and ChunkRefs (#9536)
* TSDB: demistify seriesRefs and ChunkRefs

The TSDB package contains many types of series and chunk references,
all shrouded in uint types.  Often the same uint value may
actually mean one of different types, in non-obvious ways.

This PR aims to clarify the code and help navigating to relevant docs,
usage, etc much quicker.

Concretely:

* Use appropriately named types and document their semantics and
  relations.
* Make multiplexing and demuxing of types explicit
  (on the boundaries between concrete implementations and generic
  interfaces).
* Casting between different types should be free.  None of the changes
  should have any impact on how the code runs.

TODO: Implement BlockSeriesRef where appropriate (for a future PR)

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* feedback

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* agent: demistify seriesRefs and ChunkRefs

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>
2021-11-06 15:40:04 +05:30
Ganesh Vernekar c8b267efd6
Get histograms from TSDB to the rate() function implementation
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-11-03 19:04:18 +05:30
Mateusz Gozdek 1a6c2283a3 Format Go source files using 'gofumpt -w -s -extra'
Part of #9557

Signed-off-by: Mateusz Gozdek <mgozdekof@gmail.com>
2021-11-02 19:52:34 +01:00
beorn7 a9008f5423 Merge branch 'main' into sparsehistogram 2021-10-19 17:14:23 +02:00
Dieter Plaetinck d5afe0a577
TSDB: Use a dedicated head chunk reference type (#9501)
* Use dedicated Ref type

Throughout the code base, there are reference types masked as
regular integers.  Let's use dedicated types.  They are
equivalent, but clearer semantically.
This also makes it trivial to find where they are used,
and from uses, find the centralized docs.

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* postpone some work until after possible return

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* clarify

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* rename feedback

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* skip header is up to caller

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>
2021-10-13 17:44:32 +05:30
Ganesh Vernekar 85e6686f84
Add unit test for counter reset header
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-10-13 15:57:42 +05:30
beorn7 7a8bb8222c Style cleanup of all the changes in sparsehistogram so far
A lot of this code was hacked together, literally during a
hackathon. This commit intends not to change the code substantially,
but just make the code obey the usual style practices.

A (possibly incomplete) list of areas:

* Generally address linter warnings.

* The `pgk` directory is deprecated as per dev-summit. No new packages should
  be added to it. I moved the new `pkg/histogram` package to `model`
  anticipating what's proposed in #9478.

* Make the naming of the Sparse Histogram more consistent. Including
  abbreviations, there were just too many names for it: SparseHistogram,
  Histogram, Histo, hist, his, shs, h. The idea is to call it "Histogram" in
  general. Only add "Sparse" if it is needed to avoid confusion with
  conventional Histograms (which is rare because the TSDB really has no notion
  of conventional Histograms). Use abbreviations only in local scope, and then
  really abbreviate (not just removing three out of seven letters like in
  "Histo"). This is in the spirit of
  https://github.com/golang/go/wiki/CodeReviewComments#variable-names

* Several other minor name changes.

* A lot of formatting of doc comments. For one, following
  https://github.com/golang/go/wiki/CodeReviewComments#comment-sentences
  , but also layout question, anticipating how things will look like
  when rendered by `godoc` (even where `godoc` doesn't render them
  right now because they are for unexported types or not a doc comment
  at all but just a normal code comment - consistency is queen!).

* Re-enabled `TestQueryLog` and `TestEndopints` (they pass now,
  leaving them disabled was presumably an oversight).

* Bucket iterator for histogram.Histogram is now created with a
  method.

* HistogramChunk.iterator now allows iterator recycling. (I think
  @dieterbe only commented it out because he was confused by the
  question in the comment.)

* HistogramAppender.Append panics now because we decided to treat
  staleness marker differently.

Signed-off-by: beorn7 <beorn@grafana.com>
2021-10-11 13:02:03 +02:00
beorn7 fd5ea4e0b5 Merge branch 'main' into sparsehistogram 2021-10-07 23:16:42 +02:00
Ganesh Vernekar 10d4cb6dc0
Merge remote-tracking branch 'upstream/main' into release-2.30-merge 2021-10-05 20:35:14 +05:30
Ganesh Vernekar 10bc6e80ee
Fix panic on failed snapshot replay and don't hard fail replay on disabled exemplars (#9438)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-10-05 10:51:25 +05:30
Darshan Chaudhary 1f688657bf
Call delete on head if interval overlaps (#9151)
* Call delete on head if interval overlaps

Signed-off-by: darshanime <deathbullet@gmail.com>

* Garbage collect tombstones during head gc

Signed-off-by: darshanime <deathbullet@gmail.com>

* Truncate tombstones before min time during head gc

Signed-off-by: darshanime <deathbullet@gmail.com>

* Lock less by deleting all keys in a single pass

Signed-off-by: darshanime <deathbullet@gmail.com>

* Pass map to DeleteTombstones

Signed-off-by: darshanime <deathbullet@gmail.com>

* Create new slice to replace old one

Signed-off-by: darshanime <deathbullet@gmail.com>
2021-09-16 12:20:03 +05:30
Ganesh Vernekar 30534e99d9
Take snapshot only after closing the WAL (#9328)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-09-13 18:30:41 +05:30
Bryan Boreham 87d909df4a
Remove symbols map from TSDB head (#9301)
This saves memory, effort and locking.

Since every symbol is also added to postings, `Symbols()` can be
implemented there instead. This now has to build a map for
deduplication, but `Symbols()` is only called for compaction, and `gc()`
used to rebuild the symbols map after every compaction so not an
additional cost.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2021-09-08 14:48:48 +05:30
Ganesh Vernekar 1315d8ecb6
Remove query hacks in the API and fix metrics (#9275)
* Remove query hacks in the API and fix metrics

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Tests for the metrics

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Better way to count series on restart

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-08-31 17:01:19 +05:30
Ganesh Vernekar 35b1a82594
Exemplars in snapshot (#9255)
* Exemplars in snapshot

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix lint

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Add docs

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix lint

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix comments

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-08-30 19:34:38 +05:30
Ganesh Vernekar eeace6bcab
Add couple of metrics to track sparse histograms in TSDB (#9271)
* Add couple of metrics to track sparse histograms in TSDB

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix Beorn's comments

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-08-30 19:08:44 +05:30
Ganesh Vernekar 8a5d8c15e3
Do not replay checkpoint if it is covered by snapshot (#9226)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-08-25 21:48:55 +05:30
Ganesh Vernekar 328a74ca36
Fix bugs and add enhancements to the chunk snapshot (#9185)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-08-17 18:08:16 +01:00
Julien Pivotto cab96a06ef
Merge release 2.29 in main (#9196)
* PromQL: Fix start and end keywords masking label and metric names

This commit fixes an issue with the "at modifier" that introduced two
new keywords: `start` and `end`. In grouping options and in metric
names, these keywords took precedence over metric or label names, so
that those metrics and labels could no longer be referenced.

Signed-off-by: Clayton Peters <clayton.peters@man.com>

* Add in additional tests for metrics and/or labels called start/end.

Signed-off-by: Clayton Peters <clayton.peters@man.com>

* *: Cut 2.29.0-rc.0

Signed-off-by: Frederic Branczyk <fbranczyk@gmail.com>

* VERSION: bump to 2.29.0-rc.0

Signed-off-by: Frederic Branczyk <fbranczyk@gmail.com>

* Remove experimental wording on size-based retention

Followup of #9004

Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>

* Fix PR reference in changelog

Signed-off-by: George Brighton <george@gebn.co.uk>

* Describe EC2 availability zone IDs at most once per refresh (#9142)

Signed-off-by: George Brighton <george@gebn.co.uk>

* Describe EC2 availability zones at most once per SD load

Closes #9142.

Signed-off-by: George Brighton <george@gebn.co.uk>

* Incorporate feedback

Signed-off-by: George Brighton <george@gebn.co.uk>

* Integrate feedback

Signed-off-by: George Brighton <george@gebn.co.uk>

* Add a compatibility note for macOS users.

Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>

* *: Cut v2.29.0-rc.1

Signed-off-by: Frederic Branczyk <fbranczyk@gmail.com>

* Fix `kuma_sd` targetgroup reporting (#9157)

* Bundle all xDS targets into a single group

Signed-off-by: austin ce <austin.cawley@gmail.com>

* *: cut v2.29.0-rc.2

Signed-off-by: Frederic Branczyk <fbranczyk@gmail.com>

* Rename links

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* bump codemirror-promql to 0.17.0

Signed-off-by: Augustin Husson <husson.augustin@gmail.com>

* *: cut v2.29.0

Signed-off-by: Frederic Branczyk <fbranczyk@gmail.com>

* tsdb: align atomically accessed int64 (#9192)

This prevents a panic in 32-bit archs:
https://pkg.go.dev/sync/atomic#pkg-note-BUG

Fixed #9190

Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>

* Release 2.29.1 (#9193)

Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>

Co-authored-by: Clayton Peters <clayton.peters@man.com>
Co-authored-by: Frederic Branczyk <fbranczyk@gmail.com>
Co-authored-by: George Brighton <george@gebn.co.uk>
Co-authored-by: Austin Cawley-Edwards <austin.cawley@gmail.com>
Co-authored-by: Levi Harrison <git@leviharrison.dev>
Co-authored-by: Augustin Husson <husson.augustin@gmail.com>
2021-08-12 18:38:06 +02:00
Ganesh Vernekar f0688c21d6
Log sparse histograms into WAL and replay from it (#9191)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-08-11 17:38:48 +05:30
Ganesh Vernekar 095f572d4a
Sync sparsehistogram branch with main (#9189)
* Fix `kuma_sd` targetgroup reporting (#9157)

* Bundle all xDS targets into a single group

Signed-off-by: austin ce <austin.cawley@gmail.com>

* Snapshot in-memory chunks on shutdown for faster restarts (#7229)

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Rename links

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Remove Individual Data Type Caps in Per-shard Buffering for Remote Write (#8921)

* Moved everything to nPending buffer

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Simplify exemplar capacity addition

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Added pre-allocation

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Don't allocate if not sending exemplars

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Avoid deadlock when processing duplicate series record (#9170)

* Avoid deadlock when processing duplicate series record

`processWALSamples()` needs to be able to send on its output channel
before it can read the input channel, so reads to allow this in case the
output channel is full.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* processWALSamples: update comment

Previous text seems to relate to an earlier implementation.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* Optimise WAL loading by removing extra map and caching min-time (#9160)

* BenchmarkLoadWAL: close WAL after use

So that goroutines are stopped and resources released

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* BenchmarkLoadWAL: make series IDs co-prime with #workers

Series are distributed across workers by taking the modulus of the
ID with the number of workers, so multiples of 100 are a poor choice.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* BenchmarkLoadWAL: simulate mmapped chunks

Real Prometheus cuts chunks every 120 samples, then skips those samples
when re-reading the WAL. Simulate this by creating a single mapped chunk
for each series, since the max time is all the reader looks at.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* Fix comment

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* Remove series map from processWALSamples()

The locks that is commented to reduce contention in are now sharded
32,000 ways, so won't be contended. Removing the map saves memory and
goes just as fast.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* loadWAL: Cache the last mmapped chunk time

So we can skip calling append() for samples it will reject.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* Improvements from code review

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* Full stops and capitals on comments

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* Cache max time in both places mmappedChunks is updated

Including refactor to extract function `setMMappedChunks`, to reduce
code duplication.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* Update head min/max time when mmapped chunks added

This ensures we have the correct values if no WAL samples are added for
that series.

Note that `mSeries.maxTime()` was always `math.MinInt64` before, since
that function doesn't consider mmapped chunks.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* Split Go and React Tests (#8897)

* Added go-ci and react-ci

Co-authored-by: Julien Pivotto <roidelapluie@inuits.eu>
Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Remove search keymap from new expression editor (#9184)

Signed-off-by: Julius Volz <julius.volz@gmail.com>

Co-authored-by: Austin Cawley-Edwards <austin.cawley@gmail.com>
Co-authored-by: Levi Harrison <git@leviharrison.dev>
Co-authored-by: Julien Pivotto <roidelapluie@inuits.eu>
Co-authored-by: Bryan Boreham <bjboreham@gmail.com>
Co-authored-by: Julius Volz <julius.volz@gmail.com>
2021-08-11 15:43:17 +05:30
Bryan Boreham 040ef175eb
Optimise WAL loading by removing extra map and caching min-time (#9160)
* BenchmarkLoadWAL: close WAL after use

So that goroutines are stopped and resources released

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* BenchmarkLoadWAL: make series IDs co-prime with #workers

Series are distributed across workers by taking the modulus of the
ID with the number of workers, so multiples of 100 are a poor choice.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* BenchmarkLoadWAL: simulate mmapped chunks

Real Prometheus cuts chunks every 120 samples, then skips those samples
when re-reading the WAL. Simulate this by creating a single mapped chunk
for each series, since the max time is all the reader looks at.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* Fix comment

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* Remove series map from processWALSamples()

The locks that is commented to reduce contention in are now sharded
32,000 ways, so won't be contended. Removing the map saves memory and
goes just as fast.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* loadWAL: Cache the last mmapped chunk time

So we can skip calling append() for samples it will reject.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* Improvements from code review

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* Full stops and capitals on comments

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* Cache max time in both places mmappedChunks is updated

Including refactor to extract function `setMMappedChunks`, to reduce
code duplication.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* Update head min/max time when mmapped chunks added

This ensures we have the correct values if no WAL samples are added for
that series.

Note that `mSeries.maxTime()` was always `math.MinInt64` before, since
that function doesn't consider mmapped chunks.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2021-08-10 14:53:31 +05:30
Ganesh Vernekar ee7e0071d1
Snapshot in-memory chunks on shutdown for faster restarts (#7229)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-08-06 17:51:01 +01:00
Ganesh Vernekar 8b70e87ab9
Merge remote-tracking branch 'upstream/main' into sparse-refactor
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-08-05 12:16:08 +05:30
Ganesh Vernekar 848cb5a6d6
Enhanced WAL replay for duplicate series record (#7438)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-08-03 20:03:54 +05:30
Ganesh Vernekar 8002a3ab80
Breakdown tsdb/head.go into multiple files (#9147)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-08-03 14:14:26 +02:00
Oleg Zaytsev f9482c5bf6
Clarify computeChunkEndTime's purpose (#9049)
I was struggling to understand the purpose of this method until I
tweaked the tests, so I decided to write down my observations.

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
2021-07-28 18:39:05 +05:30
Oleg Zaytsev b1ed4a0a66
LabelNames API with matchers (#9083)
* Push the matchers for LabelNames all the way into the index.

NB This doesn't actually implement it in the index, just plumbs it through for now...

Signed-off-by: Tom Wilkie <tom@grafana.com>

* Hack it up.  Does not work.

Signed-off-by: Tom Wilkie <tom@grafana.com>

* Revert changes I don't understand

Can't see why do we need to hold a mutex on symbols, and the purpose of
the LabelNamesFor method.

Maybe I'll need to re-add this later.

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Implement LabelNamesFor

This method provides the label names that appear in the postings
provided. We do that deeper than the label values because we know
beforehand that most of the label names we'll be the same across
different postings, and we don't want to go down an up looking up the
same symbols for all different series.

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Mutex on symbols should be unlocked

However, I still don't understand why do we need a mutex here.

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Fix head.LabelNamesFor

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Implement mockIndex LabelNames with matchers

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Nitpick on slice initialisation

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Add tests for LabelNamesWithMatchers

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Fix the mutex mess on head.LabelValues/LabelNames

I still don't see why we need to grab that unrelated mutex, but at least
now we're grabbing it consistently

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Check error after iterating postings

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Use the error from posting when there was en error in postings

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Update storage/interface.go comment

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

* Update tsdb/index/index.go comment

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

* Update tsdb/index/index.go wrapped error msg

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

* Update tsdb/index/index.go wrapped error msg

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

* Update tsdb/index/index.go warpped error msg

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

* Remove unneeded comment

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Add testcases for LabelNames w/matchers in api.go

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Use t.Cleanup() instead of defer in tests

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

Co-authored-by: Tom Wilkie <tom@grafana.com>
Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
2021-07-20 18:08:08 +05:30
Ganesh Vernekar 59d02b5ef0
tsdb: Block Head GC till pending readers are done reading (#9081)
* tsdb: Block Head GC till pending readers are done reading

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix review comments

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix review comments 2

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix the exclusiveness of maxt in WaitForPendingReadersInTimeRange

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-07-20 14:17:20 +05:30
Martin Disibio 1bcd13d6b5
Exemplar resize (#8974)
* Create experimental circular buffer resize method, benchmarks

Signed-off-by: Martin Disibio <mdisibio@gmail.com>

* Optimize exemplar resize to only replay as many exemplars as needed

Signed-off-by: Martin Disibio <mdisibio@gmail.com>

* More comments, benchmark AddExemplar

Signed-off-by: Martin Disibio <mdisibio@gmail.com>

* optimizations

Signed-off-by: Martin Disibio <mdisibio@gmail.com>

* comment

Signed-off-by: Martin Disibio <mdisibio@gmail.com>

* Slight refactor of resize benchmark + make use of resize via runtime
reloadable storage config.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Some more config related changes.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Address some review comments.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Address more review comments.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Refactor to remove usage of noopExemplarStorage and avoid race condition
when resizing from Head code.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Fix or add comments to clarify some of the new behaviour.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* fix potential panics related to negative exemplar buffer lengths

Signed-off-by: Callum Styan <callumstyan@gmail.com>

Co-authored-by: Callum Styan <callumstyan@gmail.com>
2021-07-20 10:22:57 +05:30
ide-rea 14b24d15b0
update checkpoint replay status (#8898)
* Consider  wal checkpoint replay status

Signed-off-by: XiaoYu Zhang <ideoutrea@163.com>

* Fix tests failed

Signed-off-by: XiaoYu Zhang <ideoutrea@163.com>

* Update checkpoint replay status

Signed-off-by: XiaoYu Zhang <ideoutrea@163.com>
2021-07-13 15:38:07 +05:30
Bryan Boreham dc8f505595
tsdb: coalesce lock/unlock operations for append (#9061)
Fetch the low watermark value under the same lock as we need for the
appender, rather than releasing then re-aquiring a lock on the same
Mutex.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2021-07-07 18:58:20 +05:30
beorn7 01957eee2b Fix interjections even more
Signed-off-by: beorn7 <beorn@grafana.com>
2021-07-05 23:59:33 +02:00
Ganesh Vernekar 1acb701e5c
Fix TSDB race while reading histograms
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-07-05 21:51:35 +05:30
Ganesh Vernekar 9f206a7a05
Fix race in TSBD while reading/writing histograms (#9051)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-07-05 21:27:26 +05:30
Dieter Plaetinck 99ae04bb6f add SHS chunk recoding and head cutting to head block (no tests yet)
Signed-off-by: Dieter Plaetinck <dieter@grafana.com>
2021-07-05 15:56:38 +03:00
Ganesh Vernekar 4c01ff5194
Bunch of fixes for sparse histograms (#9043)
* Do not panic on histoAppender.Append

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* M-map all chunks on shutdown

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Support negative schema for querying

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-07-03 23:04:34 +05:30
Ganesh Vernekar f4d3af73f0
Query histograms from TSDB and unit test for append+query (#9022)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-06-30 20:18:13 +05:30
Ganesh Vernekar 04ad56d9b8
Append sparse histograms into the Head block (#9013)
* Append sparse histograms into the Head block

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Add AtHistogram() to Iterator interface. Make HistoChunk conform to Chunk interface.

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-06-29 20:08:46 +05:30
Dieter Plaetinck 58917d1b76
sparsehistogram: integer types and timestamp separation (#9014)
* integer types and timestamp separation

1) unify types to int64. as suggested by beorn. we want to support
   counters going down (resets) even if we plan to create new chunks for
   now, in that case
2) histogram type doesn't know its own timestamp. include it separately
   in appending and iteration

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* correction: count and zeroCount to remain unsigned

to make api more resilient and that's what we use in protobuf anyway

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>

* temp hack. Ganesh will fix

Signed-off-by: Dieter Plaetinck <dieter@grafana.com>
2021-06-29 19:27:59 +05:30
Ganesh Vernekar 64bea6999e
HistogramAppender interface for sparse histograms (#9007)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-06-28 20:30:55 +05:30
Levi Harrison b5f6f8fb36 Switched to go-kit/log
Signed-off-by: Levi Harrison <git@leviharrison.dev>
2021-06-11 12:28:36 -04:00
Levi Harrison 7bc11dcb06
React UI: Add Starting Screen (#8662)
* Added walreplay API endpoint

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Added starting page to react-ui

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Documented the new endpoint

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Fixed typos

Signed-off-by: Levi Harrison <git@leviharrison.dev>

Co-authored-by: Julius Volz <julius.volz@gmail.com>

* Removed logo

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Changed isResponding to isUnexpected

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Changed width of progress bar

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Changed width of progress bar

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Added DB stats object

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Updated starting page to work with new fields

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Passing nil

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Passing nil (pt. 2)

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Passing nil (pt. 3)

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Passing nil (and also implementing a method this time) (pt. 4)

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Passing nil (and also implementing a method this time) (pt. 5)

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Changed const to let

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Passing nil (pt. 6)

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Remove SetStats method

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Added comma

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Changed api

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Changed to triple equals

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Fixed data response types

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Don't return pointer

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Changed version

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Fixed interface issue

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Fixed pointer

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Fixed copying lock value error

Signed-off-by: Levi Harrison <git@leviharrison.dev>

Co-authored-by: Julius Volz <julius.volz@gmail.com>
2021-06-05 15:29:32 +01:00
Callum Styan 8fd73b1d28
Add Exemplar Remote Write support (#8296)
* Write exemplars to the WAL and send them over remote write.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Update example for exemplars, print data in a more obvious format.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Add metrics for remote write of exemplars.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Fix incorrect slices passed to send in remote write.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* We need to unregister the new metrics.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Address review comments

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Order of exemplar append vs write exemplar to WAL needs to change.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Several fixes to prevent sending uninitialized or incorrect samples with an exemplar. Fix dropping exemplar for missing series. Add tests for queue_manager sending exemplars

Signed-off-by: Martin Disibio <mdisibio@gmail.com>

* Store both samples and exemplars in the same timeseries buffer to remove the alloc when building final request, keep sub-slices in separate buffers for re-use

Signed-off-by: Martin Disibio <mdisibio@gmail.com>

* Condense sample/exemplar delivery tests to parameterized sub-tests

Signed-off-by: Martin Disibio <mdisibio@gmail.com>

* Rename test methods for clarity now that they also handle exemplars

Signed-off-by: Martin Disibio <mdisibio@gmail.com>

* Rename counter variable. Fix instances where metrics were not updated correctly

Signed-off-by: Martin Disibio <mdisibio@gmail.com>

* Add exemplars to LoadWAL benchmark

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* last exemplars timestamp metric needs to convert value to seconds with
ms precision

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Process exemplar records in a separate go routine when loading the WAL.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Address review comments related to clarifying comments and variable
names. Also refactor sample/exemplar to enqueue prompb types.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Regenerate types proto with comments, update protoc version again.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Put remote write of exemplars behind a feature flag.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Address some of Ganesh's review comments.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Move exemplar remote write feature flag to a config file field.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Address Bartek's review comments.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Don't allocate exemplar buffers in queue_manager if we're not going to
send exemplars over remote write.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Add ValidateExemplar function, validate exemplars when appending to head
and log them all to WAL before adding them to exemplar storage.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Address more reivew comments from Ganesh.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Add exemplar total label length check.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Address a few last review comments

Signed-off-by: Callum Styan <callumstyan@gmail.com>

Co-authored-by: Martin Disibio <mdisibio@gmail.com>
2021-05-06 13:53:52 -07:00
Fiona Liao 9b83d8330a
Fix memSafeIterator.Seek() (#8748)
* Add range query test cases

This includes a couple of failing ones that double count some points due
to the iterator seek bug.

Co-authored-by: Oleg Zaytsev <mail@olegzaytsev.com>
Signed-off-by: Fiona Liao <fiona.y.liao@gmail.com>

* Add Seek() implementation for memSafeIterator

Previously, calling memSafeIterator.Seek() would call the Seek() method
on its embedded iterator. This was causing the embedded iterator and the
memSafeIterator to get out of sync because when the embedded Seek()
moved to the next element of the embedded iterator, memSafeIterator
didn't "know" about it. memSafeIterator has to "know" when the embedded
iterator has moved to be able to work out when it should be reading from
its buffer rather than the embedded iterator.

Used same logic as for xorIterator.Seek() (which in runtime is used as
the embedded iterator) - return false if the iterator has an error and
try to move to next element if the required time hasn't been reached, or
if no elements have been read yet. The memSafeIterator.Next() method is
being called so memSafeIterator.i is always accurate.

Signed-off-by: Fiona Liao <fiona.y.liao@gmail.com>

* Add tsdb package test

Signed-off-by: Fiona Liao <fiona.y.liao@gmail.com>

Co-authored-by: Oleg Zaytsev <mail@olegzaytsev.com>
2021-04-27 00:43:22 +02:00
Marco Pracucci 52df5ef7a3
TSDB: do not allocate exemplars buffer if exemplars are disabled (#8746)
Signed-off-by: Marco Pracucci <marco@pracucci.com>
2021-04-21 20:02:21 +05:30
Bartlomiej Plotka 80545bfb2e
Instrumented circular exemplar storage. (#8712)
* Instrumented circular storage.

Fixes: https://github.com/prometheus/prometheus/issues/8708
Fixes: https://github.com/prometheus/prometheus/issues/8707

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

* Fixed CB.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

* Addressed Julien comments.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

* Addressed Callum comments.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
2021-04-16 13:44:53 +01:00
Bryan Boreham c7a62b95ce
GetRef() now returns the label set (#8641)
The purpose of GetRef() is to allow Append() to be called without
the caller needing to copy the labels. To avoid a race where a series
is removed from TSDB between the calls to GetRef() and Append(), we
return TSDB's copy of the labels.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2021-03-24 15:24:58 +00:00
Bryan Boreham d614ae9ecf
[RFC] Add method to get reference number for TSDB Appender (#8600)
* Add method to get reference number for TSDB Appender

In situations where we need to copy labels before calling Add(),
GetRef() allows to check first, then call AddFast() in the case that the series
is already known.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* Add explicit interface for GetRef() method

Suggested in code review by @bwplotka

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* Rename OptionalGetRef to GetRef

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

* Simplify return value of GetRef()

0 can be relied on to mean 'no reference'

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2021-03-19 19:28:55 +00:00
Marco Pracucci 6248e685b2
TSDB: optimize series creation on PreCreation() failure (#8620)
Signed-off-by: Marco Pracucci <marco@pracucci.com>
2021-03-18 20:53:50 +05:30
Callum Styan 289ba11b79
Add circular in-memory exemplars storage (#6635)
* Add circular in-memory exemplars storage

Signed-off-by: Callum Styan <callumstyan@gmail.com>
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
Signed-off-by: Ganesh Vernekar <cs15btech11018@iith.ac.in>
Signed-off-by: Martin Disibio <mdisibio@gmail.com>

Co-authored-by: Ganesh Vernekar <cs15btech11018@iith.ac.in>
Co-authored-by: Tom Wilkie <tom.wilkie@gmail.com>
Co-authored-by: Martin Disibio <mdisibio@gmail.com>

* Fix some comments, clean up exemplar metrics struct and exemplar tests.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Fix exemplar query api null vs empty array issue.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

Co-authored-by: Ganesh Vernekar <cs15btech11018@iith.ac.in>
Co-authored-by: Tom Wilkie <tom.wilkie@gmail.com>
Co-authored-by: Martin Disibio <mdisibio@gmail.com>
2021-03-16 15:17:45 +05:30