Commit graph

750 commits

Author SHA1 Message Date
Ganesh Vernekar 2820e327db
tsdb: Add staleness handling for FloatHistogram
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-12-28 14:48:39 +05:30
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
Bryan Boreham 1848623c77 tsdb: re-use iterator when stepping through chunks
Saves memory allocations, hence reduces garbage-collection overheads.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-12-22 17:01:47 +00:00
Bryan Boreham ccea61c7bf
Merge pull request #11717 from bboreham/labels-abstraction
Add and use abstractions over labels.Labels
2022-12-20 17:23:39 +00:00
Ganesh Vernekar 6fd89a6fd2
Add chunk encoding for float histogram (#11716)
Signed-off-by: Marc Tudurí <marctc@protonmail.com>
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
Co-authored-by: Marc Tudurí <marctc@protonmail.com>
2022-12-20 15:33:32 +05:30
Bryan Boreham 10b27dfb84 Simplify IndexReader.Series interface
Instead of passing in a `ScratchBuilder` and `Labels`, just pass the
builder and the caller can extract labels from it. In many cases the
caller didn't use the Labels value anyway.

Now in `Labels.ScratchBuilder` we need a slightly different API: one
to assign what will be the result, instead of overwriting some other
`Labels`. This is safer and easier to reason about.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-12-19 15:22:09 +00:00
Bryan Boreham 4b6a4d1425 Update package tsdb tests for new labels.Labels type
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-12-19 15:22:09 +00:00
Bryan Boreham ce2cfad0cb Update package tsdb/record for new labels.Labels type
Implement decoding via labels.ScratchBuilder, which we retain and re-use
to reduce memory allocations.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-12-19 15:22:09 +00:00
Bryan Boreham 543c318ec2 Update package tsdb for new labels.Labels type
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-12-19 15:22:09 +00:00
Bryan Boreham f0ec81badd Update package tsdb/test for new labels.Labels type
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-12-19 15:22:09 +00:00
Bryan Boreham 14ad2e780b Update package tsdb/agent for new labels.Labels type
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-12-19 15:22:09 +00:00
Bryan Boreham a5bdff414b Update package tsdb/index tests for new labels.Labels type
Note in one cases we needed an extra copy of labels in case they change.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-12-19 15:22:09 +00:00
Bryan Boreham d3d96ec887 tsdb/index: use ScratchBuilder to create Labels
This necessitates a change to the `tsdb.IndexReader` interface:
`index.Reader` is used from multiple goroutines concurrently, so we
can't have state in it.

We do retain a `ScratchBuilder` in `blockBaseSeriesSet` which is
iterator-like.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-12-19 15:22:09 +00:00
Bryan Boreham 927a14b0e9 Update package tsdb/index for new labels.Labels type
Incomplete - needs further changes to `Decoder.Series()`.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-12-19 15:22:09 +00:00
Bryan Boreham 89bf6e1df9 tsdb: Tidy up some test code
Use simpler utility function to create Labels objects, making fewer
assumptions about the data structure.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-12-15 19:39:46 +00:00
Bryan Boreham 0853250695 Review feedback
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-12-15 18:32:45 +00:00
Bryan Boreham 463f5cafdd storage: re-use iterators to save garbage
Re-use previous memory if it is already of the correct type.

In `NewListSeries` we hoist the conversion to an interface value out
so it only allocates once.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-12-15 18:32:45 +00:00
Bryan Boreham f0866c0774 tsdb: optimise block series iterators
Re-use previous memory if it is already of the correct type.

Also turn two levels of function closure into a single object that
holds the required data.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-12-15 18:32:45 +00:00
Bryan Boreham 3c7de69059 storage: allow re-use of iterators
Patterned after `Chunk.Iterator()`: pass the old iterator in so it
can be re-used to avoid allocating a new object.

(This commit does not do any re-use; it is just changing all the method
signatures so re-use is possible in later commits.)

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-12-15 18:32:45 +00:00
Julien Pivotto 475cfe8a6b Merge remote-tracking branch 'origin/release-2.40'
Signed-off-by: Julien Pivotto <roidelapluie@o11y.eu>
2022-12-14 11:22:01 +01:00
Ganesh Vernekar db99fc43e4
Merge pull request #11632 from bboreham/improve-bbss
tsdb: improve blockBaseSeriesSet scan
2022-12-14 15:05:27 +05:30
Ganesh Vernekar 54739a1465
Merge pull request #11674 from bboreham/fix-tsdb-test-mem
tsdb tests: allocate more reasonable sample slice
2022-12-14 15:01:04 +05:30
beorn7 5f366e9b62 histograms: Improve tests and fix exposed bugs
This adds negative buckets and access of float histograms to
TestHistogramChunkSameBuckets and TestHistogramChunkBucketChanges.

It also exercises a specific pattern of reusing an iterator (one where
no access has happened).

This exposes two bugs (where entries for positive buckets where used
where the corresponding entries for negative buckets should have been
used). One was fixed in #11627 (not merged), which triggered the work
in this commit.

This commit fixes both issues, so #11627 can be closed.

It also simplifies the code in the histogramIterator.Next method that
aims to recycle existing slice capacity.

Furthermore, this is on top of the release-2.40 branch because we
should probably cut a bugfix release for this.

Signed-off-by: beorn7 <beorn@grafana.com>
2022-12-12 00:08:23 +01:00
Julien Pivotto 0b302f8a39
Merge pull request #11662 from prometheus/release-2.40
Merge back release-2.40 branch again
2022-12-06 17:30:51 +01:00
Bryan Boreham 9853888f9b tsdb tests: allocate more reasonable sample slice
Typical parameters are one hour  by 1 minute step, where the
function would allocate a slice of 3.6 million samples instead of 60.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-12-05 17:15:02 +00:00
Ganesh Vernekar 72a48321da
Merge pull request #11633 from pstibrany/populate-error
Enhance "cannot populate chunk" error message to include source block ID
2022-12-02 16:28:52 +05:30
Ganesh Vernekar b8b0d45d69
Fix reset of a histogram chunk iterator
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-11-30 17:50:05 +05:30
Julien Pivotto 0372e259ba
Merge pull request #11634 from prometheus/release-2.40
Merge release-2.40 branch into main
2022-11-29 15:54:58 +01:00
Bryan Boreham 6bdecf377c
Switch from 'sanity' to more inclusive lanuage (#9376)
* Switch from 'sanity' to more inclusive lanuage

"Removing ableist language in code is important; it helps to create and
maintain an environment that welcomes all developers of all backgrounds,
while emphasizing that we as developers select the most articulate,
precise, descriptive language we can rather than relying on metaphors.

The phrase sanity check is ableist, and unnecessarily references mental
health in our code bases. It denotes that people with mental illnesses
are inferior, wrong, or incorrect, and the phrase sanity continues to be
used by employers and other individuals to discriminate against these
people."

From https://gist.github.com/seanmhanson/fe370c2d8bd2b3228680e38899baf5cc

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-11-28 17:09:18 +00:00
Peter Štibraný af838ccf83 Include source block in error message when loading chunk fails.
Signed-off-by: Peter Štibraný <pstibrany@gmail.com>
2022-11-28 09:12:54 +01:00
Bryan Boreham 1226922ff5 tsdb: improve blockBaseSeriesSet scan
Inverting the test for chunks deleted by tombstones makes all three
rejections consistent, and also avoids the case where a chunk is
excluded but still causes `trimFront` or `trimBack` to be set.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-11-26 15:23:02 +00:00
Bryan Boreham 0c05f95e92 tsdb: use smaller allocation in blockBaseSeriesSet
This reduces garbage, hence goes faster, when a short time range is
required compared to the amount of chunks in the block. For example
recording rules and alerts often look only at the last few minutes.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-11-26 14:56:22 +00:00
Ganesh Vernekar ad79fb9f25
Do not error on empty chunk during iteration in populateWithDelChunkSeriesIterator
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-11-23 17:32:28 +05:30
Ganesh Vernekar d0e683e26d
Add TestCompactHeadWithDeletion to test compaction failure after deletion
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-11-23 17:31:18 +05:30
Ganesh Vernekar 42633bd05c
Merge pull request #11485 from t00350320/prometheus-office
GetRefByhash() will query a label's ref with hash value rather than lset.Hash().
2022-11-16 15:09:49 +01:00
tanghengjian 982007ecab
GetRefByhash will query a label's ref with hash value rather than lset.Hash().
Signed-off-by: tanghengjian <1040104807@qq.com>
2022-11-16 14:13:59 +01:00
Oleg Zaytsev 8553a98267
Optimize postings offset table reading (#11535)
* Add BenchmarkOpenBlock

* Use specific types when reading offset table

Instead of reading a generic-ish []string, we can read a generic type
which would be specifically labels.Label.

This avoid allocating a slice that escapes to the heap, making it both
faster and more efficient in terms of memory management.

* Update error message for unexpected number of keys

* s/posting offset table/postings offset table/

* Remove useless lastKey assignment

* Use two []bytes vars, simplify

Applied PR feedback: removed generics, moved the label indices reading
to that specific test as we're not using it in production anyway, we're
just testing what we've just built.

Also using two []bytes variables for name and value that use the backing
buffer instead of using strings, this reduces allocations a lot as we
only copy them when we store them (this is optimized by the compiler).

* Fix the dumb bug

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
Co-authored-by: Marco Pracucci <marco@pracucci.com>
2022-11-14 17:48:16 +01:00
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 fa6e05903f
Merge pull request #11447 from prometheus/sparsehistogram
Add Support for Native Histograms

This PR merges all the coding work that has been done in sparsehistogram branch over the last 1 year into main branch.

Design doc on native histograms: https://docs.google.com/document/d/1cLNv3aufPZb3fNfaJgdaRBZsInZKKIHo9E6HinJVbpM/edit
Some sneak peak: https://www.youtube.com/watch?v=T2GvcYNth9U
2022-10-26 17:10:46 -04:00
Viacheslav Panasovets 3d2e18bad5
Fix time.Since() in defer. Wrap in anonymous function (#11489)
Function arguments in defer evaluated during definition of defer, not
during execution

Signed-off-by: Slavik Panasovets <slavik@google.com>

Signed-off-by: Slavik Panasovets <slavik@google.com>
2022-10-26 00:26:12 +02:00
Björn Rabenstein 503ffba49a
chunkenc: Slightly optimize xorWrite/xoRead (#11476)
With these changes, the "happy path" when the leading and trailing
number of bits don't need an update, fewer operations are needed.

The change is probably very marginal (no change in the benchmark added
here, but the benchmark also doesn't cover non-changing values), and
an argument could me made that avoiding pointers also has its
benefits.

However, I think that reducing the number of return values improves
readability. Which convinced me that I should at least propose this.

Signed-off-by: beorn7 <beorn@grafana.com>
2022-10-20 15:08:01 +05:30
Ganesh Vernekar 8ee4dfd40c
Fix the build after conflict resolution
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-10-12 17:59:42 +05:30
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
Ganesh Vernekar 8e29110949
Add/Improve unit tests for compaction with histogram (#11342)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-10-12 13:31:12 +05:30
Ganesh Vernekar 507bfa46fd
Fix HistogramChunk's AtFloatHistogram()
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-10-12 10:38:13 +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
Sonali Rajput 9165aedb49 Fixed broken link in tsdb README.md
Signed-off-by: Sonali Rajput <sonalirajput1088@gmail.com>
2022-10-07 16:20:20 +00:00
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 9b31adc4e8
tsdb: fix up sort call with faster slices.Sort (#11380)
This call was added by PR #11075 merged before #11318 which changed all
similar calls to `sort.Sort` into a faster one.

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

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-10-01 12:55:40 -04:00
Bryan Boreham 3330d85ba8
Replace sort.Strings and sort.Ints with faster slices.Sort (#11318)
Use new experimental package `golang.org/x/exp/slices`.

slices.Sort works on values that are directly comparable, like ints,
so avoids the overhad of an interface call to `.Less()`.

Left tests unchanged, because they don't need the speed and it may be
a cross-check that slices.Sort gives the same answer.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-09-30 20:03:56 +05:30
Bryan Boreham 7f2374b703
tsdb: faster postings sort with generic slices.Sort (#11054)
Use new experimental package `golang.org/x/exp/slices`.

Some of the speedup comes from comparing SeriesRef (which is an int64)
directly rather than through an interface `.Less()` call; some comes
from exp/slices using "pattern-defeating quicksort(pdqsort)".

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

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-09-30 20:01:32 +05:30
Ganesh Vernekar 83d738e263
Fix 'invalid magic number 0' bug (#11338)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-09-28 21:43:58 +05:30
Ganesh Vernekar f34aeefe6e
Allow overlapping blocks by default (#11331)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-09-28 19:17:54 +05:30
Robert Fratto 448cfda6c1
tsdb/agent: fix validation of default options (#9876)
* tsdb/agent: fix application of defaults

MaxTS was being incorrectly constrained to the truncation interval

* add more tests to check validation

* force MaxWALTime = MinWALTime if min > max

Signed-off-by: Robert Fratto <robertfratto@gmail.com>
2022-09-27 19:41:43 +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
Ganesh Vernekar 758e29258b
Add/Improve unit tests for compaction with histogram Part 2 (#11343)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-09-23 14:01:10 +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 af6167df58
WAL loading: don't send empty buffers over chan (#11319)
If some shards did not get any samples mapped, the buffer will be empty
so sending it over the chan to `processWALSamples()` is a waste of time.

This is especially likely now we are checking `minValidTime` before
sending.

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

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-09-20 19:43:30 +05:30
Ganesh Vernekar 2474c6fb2c
Error on amending histograms on append (#11308)
* Error on amending histograms on append

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

* Rename Matches to Equals

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

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-09-19 13:10:30 +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
Björn Rabenstein 7ad36505d5
tsdb: Update comment about a possible space optimization (#11303)
See also #11195 for the detailed reasoning.

Signed-off-by: beorn7 <beorn@grafana.com>

Signed-off-by: beorn7 <beorn@grafana.com>
2022-09-15 13:11:57 +05:30
Bryan Boreham e49d596fb1
WAL loading: check sample time is valid earlier (#11307)
There's no point splitting a sample onto the right shard and checking
if the series needs to be re-mapped, if we're only going to discard it
once it arrives at `ProcessWALSamples()`. Simply discard it earlier.

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

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-09-15 12:36:57 +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
Ganesh Vernekar 83e11014dd
Remove unnecessary tsdb/tsdbutil/buffer.go (#11302)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-09-13 19:36:32 +05:30
Ganesh Vernekar b2d01cbc57
Remove unnecessary code in encoding/decoding histograms (#11252)
* Remove unnecessary code in encoding/decoding histograms

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

* Fix review comments

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

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-09-13 19:30:54 +05:30
Bryan Boreham 136f8b0ebb
tsdb: comment reason for isolation tracking reads (#11301)
I find it useful to know why a restriction exists, to check whether that
reason still applies, or in which other places it might apply.

This is based on the note here:
https://github.com/prometheus/prometheus/pull/9270#pullrequestreview-743820956
on the PR where the original comment was added.

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

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-09-13 11:11:03 +02:00
Bryan Boreham 176fa38e76 tsdb: in tests use labels.FromStrings
Replacing code which assumes the internal structure of `Labels`.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-09-09 13:34:49 +02:00
Bryan Boreham 0437dd7cee tsdb/wal: in tests use labels.FromStrings
Replacing code which assumes the internal structure of `Labels`.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-09-09 13:34:49 +02:00
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
Julien Pivotto 96d5a32659
Update go to 1.19, set min version to 1.18 (#11279)
* Update go to 1.19, set min version to 1.18

Signed-off-by: Julien Pivotto <roidelapluie@o11y.eu>

* Update golangci-lint

Signed-off-by: Julien Pivotto <roidelapluie@o11y.eu>

Signed-off-by: Julien Pivotto <roidelapluie@o11y.eu>
2022-09-07 11:30:48 +02:00
Ganesh Vernekar 8f755f8f35
Extend createHead in tests to support histograms
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-08-29 20:18:02 +05:30
Ganesh Vernekar f540c1dbd3
Add support for histograms in WAL checkpointing (#11210)
* Add support for histograms in WAL checkpointing

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

* Fix review comments

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

* Fix tests

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

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-08-29 17:38:36 +05:30
Ganesh Vernekar 6383994f3e
Improve WAL/mmap chunks test for histograms (#11208)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-08-29 16:21:32 +05:30
Ganesh Vernekar d209a29a5b
Add unit test for histogram append and various querying scenarios (#11194)
* Add unit test for histogram append and various querying scenarios

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

* make lint happy

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

* Fix tests

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

* Fix review comments

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

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-08-29 15:35:03 +05:30
Abirdcfly 314aa45c2c
chore: remove duplicate word in comments (#11225)
Signed-off-by: Abirdcfly <fp544037857@gmail.com>

Signed-off-by: Abirdcfly <fp544037857@gmail.com>
2022-08-27 22:21:41 +02:00
Ganesh Vernekar 0f4e5196c4
Implement vertical compaction for native histograms (#11184)
* Implement vertical compaction for native histograms

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

* Fix typo

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

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-08-22 19:04:39 +05:30
Xiaochao Dong 09187fb0cc
Replay WAL concurrently without blocking (#10973)
* Replay WAL concurrently without blocking

Signed-off-by: Xiaochao Dong (@damnever) <the.xcdong@gmail.com>

* Resolve review comments

Signed-off-by: Xiaochao Dong (@damnever) <the.xcdong@gmail.com>

Signed-off-by: Xiaochao Dong (@damnever) <the.xcdong@gmail.com>
2022-08-17 19:23:57 +05:30
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
Xiaochao Dong 1078081aec
Fix race condition when updating lastSeriesID during loading chunk snapshot (#11099)
Signed-off-by: Xiaochao Dong (@damnever) <the.xcdong@gmail.com>
2022-08-04 13:39:14 +05:30
Levi Harrison 77a7af4461
Add histogram validation (#11052)
* Add histogram validation

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

* Correct negative offset validation

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

* Address review comments

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

* Validation benchmark

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

* Add more checks

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

* Attempt to fix tests

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

* Fix stuff

Signed-off-by: Levi Harrison <git@leviharrison.dev>
2022-07-29 09:52:49 -05:00
Levi Harrison cb8582637a
Implement rollback for histograms (#11071)
Signed-off-by: Levi Harrison <git@leviharrison.dev>
2022-07-29 14:18:53 +05:30
Bryan Boreham 00ec720c29
tsdb: extract functions to encode and decode labels (#11045)
* tsdb/record: Extract functions to encode and decode labels

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

* tsdb: make use of Encode/Decode Labels

Simplify the code by re-using routines from tsdb/record.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-07-26 20:12:00 +05:30
Paschalis Tsilias a0f7c31c26
Fix type byte of WAL metadata records in docs (#11035)
Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
2022-07-19 18:22:02 +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
ZhangJian He 95b7d058ac
Fix markdown syntax in tsdb index.md (#11032)
* Fix markdown syntax in tsdb index.md

Signed-off-by: ZhangJian He <shoothzj@gmail.com>

* Update tsdb/docs/format/index.md

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

Signed-off-by: ZhangJian He <shoothzj@gmail.com>
2022-07-18 04:28:52 -07:00
Levi Harrison 3d538351f6
Recognize exemplar record type in WAL watcher metrics (#11008)
* Add exemplar record case

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

* recordType() -> Type.String()

Signed-off-by: Levi Harrison <git@leviharrison.dev>
2022-07-18 15:54:11 +05:30
Levi Harrison 08f3ddb864
Sparse histogram remote-write support (#11001) 2022-07-14 09:13:12 -04:00
beorn7 3ce988b031 Merge branch 'sparsehistogram' into beorn7/sparsehistogram 2022-07-13 18:07:54 +02:00
beorn7 28f028e938 Merge branch 'main' into sparsehistogram 2022-07-12 19:07:13 +02:00
beorn7 5d14046d28 tsdb: Fix chunk handling during appendHistogram
Previously, the maxTime wasn't updated properly in case of a recoding
happening.

My apologies for reformatting many lines for line length. During the
bug hunt, I tried to make things more readable in a reasonably wide
editor window.

Signed-off-by: beorn7 <beorn@grafana.com>
2022-07-06 18:44:53 +02:00
beorn7 642c5758ff tsdb: Expose histogram append bug
Signed-off-by: beorn7 <beorn@grafana.com>
2022-07-06 18:44:45 +02:00
beorn7 49be0784b4 tsdb: Fix chunk handling during histogram recoding
Previously, the maxTime wasn't updated properly in case of a recoding
happening.

My apologies for reformatting many lines for line length. During the
bug hunt, I tried to make things more readable in a reasonably wide
editor window.

Signed-off-by: beorn7 <beorn@grafana.com>
2022-07-06 14:34:02 +02:00
Jesus Vazquez 6cfe44d7fd
WaitUntilIdle optimize idling time (#10878)
Relates to @bboreham optimization in https://github.com/prometheus/prometheus/pull/10859

Bryan did reduce the sleep time improving the deltas on the benchmark by
quite a lot. However I've been working on a similar implementation for
out of order and I noticed that we actually get into this method
thousands of times.

@ywwg had the brilliant idea of not always sleeping before the select
but actually make it a case in the select so we only sleep if we need
to.

The benchmark deltas are amazing

```
❯ benchstat old_implementation.txt new_implementation_using_time_after.txt
name                                                                                                     old time/op  new time/op  delta
LoadWAL/batches=10,seriesPerBatch=100,samplesPerSeries=7200,exemplarsPerSeries=0,mmappedChunkT=0-8        521ms ±25%   253ms ± 6%  -51.47%  (p=0.008 n=5+5)
LoadWAL/batches=10,seriesPerBatch=100,samplesPerSeries=7200,exemplarsPerSeries=36,mmappedChunkT=0-8       773ms ± 3%   369ms ±31%  -52.23%  (p=0.008 n=5+5)
LoadWAL/batches=10,seriesPerBatch=100,samplesPerSeries=7200,exemplarsPerSeries=72,mmappedChunkT=0-8       592ms ±28%   297ms ±28%  -49.80%  (p=0.008 n=5+5)
LoadWAL/batches=10,seriesPerBatch=100,samplesPerSeries=7200,exemplarsPerSeries=360,mmappedChunkT=0-8      547ms ± 2%  999ms ±187%     ~     (p=0.690 n=5+5)
LoadWAL/batches=10,seriesPerBatch=10000,samplesPerSeries=50,exemplarsPerSeries=0,mmappedChunkT=0-8        11.3s ± 4%    1.3s ±44%  -88.48%  (p=0.008 n=5+5)
LoadWAL/batches=10,seriesPerBatch=10000,samplesPerSeries=50,exemplarsPerSeries=2,mmappedChunkT=0-8        11.1s ± 1%    1.2s ±20%  -89.08%  (p=0.008 n=5+5)
LoadWAL/batches=10,seriesPerBatch=1000,samplesPerSeries=480,exemplarsPerSeries=0,mmappedChunkT=0-8        1.24s ± 3%   0.18s ± 7%  -85.76%  (p=0.008 n=5+5)
LoadWAL/batches=10,seriesPerBatch=1000,samplesPerSeries=480,exemplarsPerSeries=2,mmappedChunkT=0-8        1.24s ± 2%   0.18s ± 5%  -85.24%  (p=0.008 n=5+5)
LoadWAL/batches=10,seriesPerBatch=1000,samplesPerSeries=480,exemplarsPerSeries=5,mmappedChunkT=0-8        1.23s ± 5%   0.27s ±33%  -77.73%  (p=0.008 n=5+5)
LoadWAL/batches=10,seriesPerBatch=1000,samplesPerSeries=480,exemplarsPerSeries=24,mmappedChunkT=0-8       1.28s ± 1%   0.36s ± 7%  -71.51%  (p=0.008 n=5+5)
LoadWAL/batches=100,seriesPerBatch=1000,samplesPerSeries=480,exemplarsPerSeries=0,mmappedChunkT=3800-8    12.1s ± 1%    3.1s ± 6%  -74.33%  (p=0.008 n=5+5)
LoadWAL/batches=100,seriesPerBatch=1000,samplesPerSeries=480,exemplarsPerSeries=2,mmappedChunkT=3800-8    12.1s ± 1%    3.4s ± 4%  -71.94%  (p=0.008 n=5+5)
LoadWAL/batches=100,seriesPerBatch=1000,samplesPerSeries=480,exemplarsPerSeries=5,mmappedChunkT=3800-8    12.1s ± 1%    3.8s ±17%  -68.35%  (p=0.008 n=5+5)
LoadWAL/batches=100,seriesPerBatch=1000,samplesPerSeries=480,exemplarsPerSeries=24,mmappedChunkT=3800-8   12.4s ± 1%    4.0s ±18%  -67.71%  (p=0.008 n=5+5)
```

Benchmarked on Linux
```
goos: linux
goarch: amd64
pkg: github.com/prometheus/prometheus/tsdb
cpu: 11th Gen Intel(R) Core(TM) i7-1165G7 @ 2.80GHz
```

Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>
2022-06-30 15:00:04 +02:00
Julien Pivotto bacd776356
Merge pull request #10907 from damnever/fix/panic
Fix panic if series is not found when deleting series
2022-06-30 11:23:08 +02:00
Peter Štibraný ffc60d8397
Reduce chunk write queue memory usage 2 (#10874)
* Job queue

This PR reimplements chan chunkWriteJob with custom buffered queue that should use less memory, because it doesn't preallocate entire buffer for maximum queue size at once. Instead it allocates individual "segments" with smaller size.

As elements are added to the queue, they fill individual segments. When elements are removed from the queue (and segments), empty segments can be thrown away. This doesn't change memory usage of the queue when it's full, but should decrease its memory footprint when it's empty (queue will keep max 1 segment in such case).

Signed-off-by: Peter Štibraný <pstibrany@gmail.com>

* Modify test to work with low resolution timer.

Signed-off-by: Peter Štibraný <pstibrany@gmail.com>

* Improve comments.

Signed-off-by: Peter Štibraný <pstibrany@gmail.com>
2022-06-29 17:51:27 +05:30
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
Peter Štibraný 03a2313f7a
Reduce chunk write queue memory usage (#10873)
* dont waste space on the chunkRefMap
* add time factor
* add comments
* better readability
* add instrumentation and more comments
* formatting
* uppercase comments
* Address review feedback. Renamed "free" to "shrink" everywhere, updated comments and threshold to 1000.
* double space

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>
Co-authored-by: Peter Štibraný <pstibrany@gmail.com>

Co-authored-by: Mauro Stettler <mauro.stettler@gmail.com>
2022-06-17 13:11:39 +05:30
Bryan Boreham 9f77d23889
tsdb: commit data periodically in CreateBlock (#10788)
To avoid building up data in memory, commit and make a new appender
periodically.

The number `commitAfter = 10000` was chosen arbitrarily; testing with
10x more or less gives slightly worse results.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-06-17 11:26:19 +05:30
Łukasz Mierzwa d65f037def
Don't increment prometheus_tsdb_compactions_failed_total when context is canceled (#10772)
When restarting Prometheus I sometimes see:

caller=db.go:832 level=error component=tsdb msg="compaction failed" err="compact head: persist head block: 2 errors: populate block: context canceled; context canceled"

And prometheus_tsdb_compactions_failed_total metric gets incremented.
This makes it more difficult to write alerts based on
prometheus_tsdb_compactions_failed_total metric since any restart can
trigger it.

Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
2022-06-17 11:21:43 +05:30
beorn7 095b6c93dd Merge branch 'main' into sparsehistogram 2022-06-14 14:27:35 +02:00
Bryan Boreham 542b9ecdbd
tsdb: reduce sleep time when reading WAL (#10859)
The code sleeps for a short time to allow goroutines to finish, however
it seems the duration can be reduced a lot, speeding up the reading
process.

I checked using some WAL data from production, and the queue is almost
always empty at the time we enter `waitForIdle()` so there is no danger
of spinning in the tight loop.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-06-12 11:54:11 +05:30
beorn7 40ad5e284a Merge branch 'main' into beorn7/sparsehistogram 2022-06-09 20:50:30 +02:00
Bryan Boreham 9f79a6f4b5
tsdb: faster CRC check by avoiding allocations (#10789)
Instead of creating a new hashing object every time, call `crc32.Checksum`
which computes the answer without allocations.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-06-08 08:00:59 +05:30
Matej Gera 1dd247f68b
Remote Write: Rename confusing walDir parameter to dir (#10464)
* Rename walDir parameter to dir

Signed-off-by: Matej Gera <matejgera@gmail.com>

* Improve NewQueueManager comment

Signed-off-by: Matej Gera <matejgera@gmail.com>
2022-05-30 21:45:30 -07:00
David Leadbeater 57f4aab27d
Update godoc links and remove note about TSDB versioning (#10754)
Signed-off-by: David Leadbeater <dgl@dgl.cx>
2022-05-26 18:34:43 +10:00
maizige 10b677b826
fix typo (#10696)
Update doc comment

Signed-off-by: gemaizi <864321211@qq.com>
2022-05-25 18:01:45 +02:00
Filip Petkovski d3cb39044e
Fix typo in symbol table size exceeded error message (#10746)
This commit fixes a typo when reporting an error that the the symbols
table size has been exceeded.

Signed-off-by: Filip Petkovski <filip.petkovsky@gmail.com>
2022-05-25 10:40:36 +02:00
Julien Pivotto 6e3a0efe40
Make necessary change to compile promql parser to wasm (#10683)
Signed-off-by: Julien Pivotto <roidelapluie@o11y.eu>
2022-05-12 09:12:05 +02:00
Matthias Rampke 78f2645787
test(tsdb): break up repeated test to avoid timeout (#10671)
On macOS, the TestTombstoneCleanRetentionLimitsRace performs very
poorly. It takes more than a second to write out one block, and as it
writes 400 of them, we run into the 10-minute test timeout frequently.

While this doesn't fix the actual performance issue, breaking each
iteration into a subtest makes the test pass reliably (because each
iteration comfortably finishes in under a minute).

Related report: https://groups.google.com/g/prometheus-developers/c/jxQ6Ayg6VJ4/m/03H_DS9PDAAJ

Signed-off-by: Matthias Rampke <matthias@prometheus.io>
2022-05-09 00:39:26 +02:00
Łukasz Mierzwa 88f9b248b4
Correctly format error message (#10669)
Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
2022-05-06 00:42:31 +02:00
Bryan Boreham 4b9f248e85
unit tests: make all Labels sorted alphabetically (#10532)
"Labels is a sorted set of labels. Order has to be guaranteed upon
instantiation." says the comment, so fix all the tests that break this
rule.

For `BenchmarkLabelValuesWithMatchers()` and
`BenchmarkHeadLabelValuesWithMatchers()` the amount of work done changes
significantly if you put the labels in order, because all series refs
get neatly partitioned by the `tens` label, so I renamed the labels
to maintain the previous behaviour.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-05-04 23:41:36 +02:00
beorn7 654c07783c Fix deprecation
Signed-off-by: beorn7 <beorn@grafana.com>
2022-05-04 13:43:23 +02:00
beorn7 3bc711e333 Merge branch 'main' into sparsehistogram 2022-05-04 13:37:13 +02:00
Matthieu MOREL e2ede285a2
refactor: move from io/ioutil to io and os packages (#10528)
* refactor: move from io/ioutil to io and os packages
* use fs.DirEntry instead of os.FileInfo after os.ReadDir

Signed-off-by: MOREL Matthieu <matthieu.morel@cnp.fr>
2022-04-27 11:24:36 +02:00
Oleg Zaytsev af0f6da5cb
Fix chunk overflow appending samples at a variable rate (#10607)
* Add a test with variable samples rate append

This test overflows the chunk created in memseries, and the total amount
of samples in the (only) mmapped chunk is 29, instead of the 65565
appended ones.

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

* Cut new chunk when rate prediction was wrong

When appending samples at a slow rate, and then appending at a higher
rate, the prediction we made to cut a new chunk is no longer valid.
Sometimes this can even cause an overflow in the chunk, if more samples
than uint16 can hold are appended.

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

* Improve comment on 2*samplesPerChunk

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

* Assert that all chunks have less than 240 samples

Also, trigger new chunk at 240, not at more than 240

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
2022-04-20 14:54:20 +02:00
Paschalis Tsilias 40c1efe8bc
tsdb/agent: Ignore duplicate exemplars (#10595)
* tsdb/agent: Ignore duplicate exemplars

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

* Make each exemplar unique in TestCommit

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

* Re-Trigger CI for Windows and UI-related steps

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

* Change test comment to properly re-trigger pipeline

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

* Defer Close() calls for test agent and segment reader

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
2022-04-18 11:41:04 -04:00
Julien Pivotto 685ce9964d
Merge pull request #10599 from prometheus/release-2.35
Merge back release 2.35
2022-04-15 00:10:06 +02:00
Robert Fratto 286dfc70b7
tsdb/agent: port grafana/agent#676 (#10587)
* tsdb/agent: port grafana/agent#676

grafana/agent#676 fixed an issue where a loading a WAL with multiple
segments may result in ref ID collision. The starting ref ID for new
series should be set to the highest ref ID across all series records
from all WAL segments.

This fixes an issue where the starting ref ID was incorrectly set to the
highest ref ID found in the newest segment, which may not have any ref
IDs at all if no series records have been appended to it yet.

Signed-off-by: Robert Fratto <robertfratto@gmail.com>

* tsdb/agent: update terminology (s/ref ID/nextRef)

Signed-off-by: Robert Fratto <robertfratto@gmail.com>
2022-04-14 10:27:06 +02:00
chavacava 0b41fd6e71
Fix data races in WAL replay (#10571)
Signed-off-by: chavacava <salvadorcavadini+github@gmail.com>
2022-04-12 16:00:20 +05:30
beorn7 7ee1836ef5 Merge branch 'main' into sparsehistogram 2022-04-05 18:31:19 +02:00
Bryan Boreham 2c1be4df7b
tsdb: more efficient sorting of postings read from WAL at startup (#10500)
* tsdb: avoid slice-to-interface allocation in EnsureOrder

This is pulling the `seriesRefSlice` out of the loop, so the compiler
doesn't allocate a new one on the heap every time.

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

* tsdb: use pointer type in Pool for EnsureOrder

As noted by staticcheck, Pool prefers the objects in the pool to have
pointer type. This is a little more fiddly to code, but avoids
allocation of a wrapper object every time a slice is put into the pool.

Removed a comment that said fixing this has a performance penalty: not
borne out by benchmarks.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-03-30 15:10:19 +05:30
Wilbert Guo 83a2e52bc2
Add SyncForState Implementation for Ruler HA (#10070)
* continuously syncing activeAt for alerts

Signed-off-by: Yijie Qin <qinyijie@amazon.com>
Signed-off-by: Wilbert Guo <wilbeguo@amazon.com>

* add import

Signed-off-by: Yijie Qin <qinyijie@amazon.com>
Signed-off-by: Wilbert Guo <wilbeguo@amazon.com>

* Refactor SyncForState and add unit tests

Signed-off-by: Wilbert Guo <wilbeguo@amazon.com>

* Format code

Signed-off-by: Wilbert Guo <wilbeguo@amazon.com>

* Add hook for syncForState

Signed-off-by: Wilbert Guo <wilbeguo@amazon.com>

Fix go lint

Signed-off-by: Wilbert Guo <wilbeguo@amazon.com>

Refactor syncForState override implementation

Signed-off-by: Wilbert Guo <wilbeguo@amazon.com>

Add syncForState override func as argument to Update()

Signed-off-by: Wilbert Guo <wilbeguo@amazon.com>

Fix go formatting

Signed-off-by: Wilbert Guo <wilbeguo@amazon.com>

Fix circleci test errors

Signed-off-by: Wilbert Guo <wilbeguo@amazon.com>

Remove overrideFunc as argument to run()

Signed-off-by: Wilbert Guo <wilbeguo@amazon.com>

* remove the syncForState

Signed-off-by: Yijie Qin <qinyijie@amazon.com>

* use the override function to decide if need to replace the activeAt or not

Signed-off-by: Yijie Qin <qinyijie@amazon.com>

* fix test case

Signed-off-by: Yijie Qin <qinyijie@amazon.com>

* fix format

Signed-off-by: Yijie Qin <qinyijie@amazon.com>

* Trigger build

Signed-off-by: Yijie Qin <qinyijie@amazon.com>

* fixing comments

Signed-off-by: Yijie Qin <qinyijie@amazon.com>

* return the result of map of alerts instead of single one

Signed-off-by: Yijie Qin <qinyijie@amazon.com>

* upper case the QueryforStateSeries

Signed-off-by: Yijie Qin <qinyijie@amazon.com>

* use a more generic rule group post process function type

Signed-off-by: Yijie Qin <qinyijie@amazon.com>

* fix indentation

Signed-off-by: Yijie Qin <qinyijie@amazon.com>

* fix gofmt

Signed-off-by: Yijie Qin <qinyijie@amazon.com>

* fix lint

Signed-off-by: Yijie Qin <qinyijie@amazon.com>

* fixing naming

Signed-off-by: Yijie Qin <qinyijie@amazon.com>

* fix comments

Signed-off-by: Yijie Qin <qinyijie@amazon.com>

* add the lastEvalTimestamp as parameter

Signed-off-by: Yijie Qin <qinyijie@amazon.com>

* fmt

Signed-off-by: Yijie Qin <qinyijie@amazon.com>

* change funcType to func

Signed-off-by: Yijie Qin <qinyijie@amazon.com>

Co-authored-by: Yijie Qin <qinyijie@amazon.com>
Co-authored-by: Yijie Qin <63399121+qinxx108@users.noreply.github.com>
2022-03-29 02:16:46 +02:00
Howie 1291ec7185
deleting *.tmp WAL files on startup (#10317)
* fix issue #10245

Signed-off-by: lihaowei <haoweili35@gmail.com>

* minor changes

Signed-off-by: lihaowei <haoweili35@gmail.com>

* review changes

Signed-off-by: lihaowei <haoweili35@gmail.com>

* minor changes

Signed-off-by: lihaowei <haoweili35@gmail.com>
2022-03-24 16:14:14 +05:30
beorn7 f9c411604d Fix spelling errors
Signed-off-by: beorn7 <beorn@grafana.com>
2022-03-22 16:02:13 +01:00
beorn7 4210aac74a Merge branch 'main' into sparsehistogram 2022-03-22 14:47:42 +01:00
Chris Marchbanks c1387494dd
Merge pull request #10452 from prometheus/release-2.34
Merge Release 2.34 into main
2022-03-15 12:32:18 -06:00
songjiayang 8d8be43824
Update wal.md (#10442)
update exemplar record type

Signed-off-by: songjiayang <songjiayang1@gmail.com>
2022-03-15 22:33:45 +05:30
Mauro Stettler b025390cb4
Disable chunk write queue by default, allow user to configure the exact size (#10425)
* Disable chunk write queue by default

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

* update flag description

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>
2022-03-11 17:26:59 +01:00
Łukasz Mierzwa da23c4649a
Enable misspell check in golangci-lint (#10393)
Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
2022-03-03 18:11:19 +01:00
Łukasz Mierzwa a4317bf0ec
Run gofumpt on all files (#10392)
* Run gofumpt on all files

Getting golangci-lint errors when building on my laptop, possibly because I have newer version of gofumpt then what it was formatted with.
Run gofumpt -w -extra on all files as it will be needed in the future anyway.

* Update golangci-lint to v1.44.2

v1.44.0 upgraded gofumpt so bumping version in CI will help keep formatting correct for everyone

* Address golangci-lint error

Getting 'error-strings: error strings should not be capitalized or end with punctuation or a newline' from revive here.
Drop new line.

Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
2022-03-03 17:21:05 +01:00
cui fliter c9b56d1a49
all: fix some typos (#10389)
Signed-off-by: cuishuang <imcusg@gmail.com>
2022-03-03 12:03:07 +00:00
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
Björn Rabenstein d1edb006c1
Merge pull request #10341 from prometheus/release-2.33
Merge release-2.33 forward into main
2022-02-22 22:51:05 +01:00
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
Dieter Plaetinck aa8874bc56
clarify Head.appendableMinValidTime (#10303)
Signed-off-by: Dieter Plaetinck <dieter@grafana.com>
2022-02-17 16:30:48 +05:30
lwangrabbit 9fde6edbf5
tsdb/wal: Move comment of w.writer.Append(...) to the WriteTo interface (#10198)
Signed-off-by: wanglipeng <wanglipeng@huayun.com>

Co-authored-by: wanglipeng <wanglipeng@huayun.com>
2022-01-30 22:14:16 -08:00
Eng Zer Jun 3e67654d37
refactor: use T.TempDir() and B.TempDir to create temporary directory
The directory created by `T.TempDir()` and `B.TempDir()` is
automatically removed when the test and all its subtests complete.

Reference: https://pkg.go.dev/testing#T.TempDir
Reference: https://pkg.go.dev/testing#B.TempDir
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
2022-01-22 18:57:30 +08:00
Robert Fratto b71a6dbbd1
tsdb/agent: Fix deadlock from simultaneous GC and write (#10166)
* tsdb/agent: Fix deadlock from simultaneous GC and write

This commit fixes a potential deadlock where storing in-memory series
references could deadlock with a WAL GC cycle.

Signed-off-by: Robert Fratto <robertfratto@gmail.com>

* add missing license header

Signed-off-by: Robert Fratto <robertfratto@gmail.com>

* order local imports

Signed-off-by: Robert Fratto <robertfratto@gmail.com>

* align deadlock testing with discovery/manager_test.go method

Also prevents GCs from running concurrently, which could also cause a
deadlock (even though it's currently impossible for two GCs to run
concurrently).

Signed-off-by: Robert Fratto <robertfratto@gmail.com>
2022-01-19 20:23:06 +05:30
Mauro Stettler bf959b36cb
Nits after PR 10051 merge (#10159)
Signed-off-by: Marco Pracucci <marco@pracucci.com>

Co-authored-by: Marco Pracucci <marco@pracucci.com>
2022-01-19 20:20:35 +05:30
Ganesh Vernekar 129ed4ec8b
Fix Example() function in TSDB (#10153)
* Fix Example() function in TSDB

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

* Fix tests

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-01-11 17:24:03 +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
Oleg Zaytsev a83d46ee9c
Tidy postingsWithIndexHeap (#10123)
Unexported postingsWithIndexHeap's methods that don't need to be
exported, and added detailed comments.

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
2022-01-06 16:03:44 +05:30
Bryan Boreham 82860a770c
tsdb: use simpler map key to improve exemplar ingest performance (#10111)
* tsdb: fix exemplar benchmarks

Go benchmarks are expected to do an amount of work that varies with
the `b.N` parameter. Previously these benchmarks would report a result
like 0.01 ns/op, which is nonsense.

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

* tsdb: use simpler map key to improve exemplar perf

Prometheus holds an index of exemplars so it can discard the oldest one
for a series when a new one is added.
Since the keys are not for human eyes, we can use a simpler format
and save the effort of quoting label values.

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

* Exemplars: allocate index map with estimated size

This avoids Go having to re-size the map several times as it grows.
16 exemplars per series is a guess; if it is too low then the map will
be sparse, while if it is too high then the map will have to resize once
or twice.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-01-06 15:58:58 +05:30