If we are populating series for a subquery then set the interval
parameter accordingly so that downstream users could use that
information.
Signed-off-by: Giedrius Statkevičius <giedrius.statkevicius@vinted.com>
And use the new method to call to compact Histograms during
parsing. This happens for both `Histogram` and `FloatHistogram`. In
this way, if targets decide to optimize the exposition size by merging
spans with empty buckets in between, we still get a normalized
results. It will also normalize away any valid but weird
representations like empty spans, spans with offset zero, and empty
buckets at the start or end of a span.
The implementation seemed easy at first as it just turns the
`compactBuckets` helper into a generic function (which now got its own
file). However, the integer Histograms have delta buckets instead of
absolute buckets, which had to be treated specially in the generic
`compactBuckets` function. To make sure it works, I have added plenty
of explicit tests for `Histogram` in addition to the `FloatHistogram`
tests.
I have also updated the doc comment for the `Compact` method.
Based on the insights now expressed in the doc comment, compacting
with a maxEmptyBuckets > 0 is rarely useful. Therefore, this commit
also sets the value to 0 in the two cases we were using 3 so far. We
might still want to reconsider, so I don't want to remove the
maxEmptyBuckets parameter right now.
Signed-off-by: beorn7 <beorn@grafana.com>
And a few cases of `EmptyLabels()`.
Replacing code which assumes the internal structure of `Labels`.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* 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>
We print the stacktrace of a panic when query causes one, but there's no
information about the query itself, which makes it harder to debug and
reproduce the issue.
This adds the 'expr' string to the logged panic.
Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
This follow a simple function-based approach to access the count and
sum fields of a native Histogram. It might be more elegant to
implement “accessors” via the dot operator, as considered in the
brainstorming doc [1]. However, that would require the introduction of
a whole new concept in PromQL. For the PoC, we should be fine with the
function-based approch. Even the obvious inefficiencies (rate'ing a
whole histogram twice when we only want to rate each the count and the
sum once) could be optimized behind the scenes.
Note that the function-based approach elegantly solves the problem of
detecting counter resets in the sum of observations in the case of
negative observations. (Since the whole native Histogram is rate'd,
the counter reset is detected for the Histogram as a whole.)
We will decide later if an “accessor” approach is really needed. It
would change the example expression for average duration in
functions.md from
histogram_sum(rate(http_request_duration_seconds[10m]))
/
histogram_count(rate(http_request_duration_seconds[10m]))
to
rate(http_request_duration_seconds.sum[10m])
/
rate(http_request_duration_seconds.count[10m])
[1]: https://docs.google.com/document/d/1ch6ru8GKg03N02jRjYriurt-CZqUVY09evPg6yKTA1s/edit
Signed-off-by: beorn7 <beorn@grafana.com>
Essentially, this mirrors the existing behavior for negative buckets:
If a histogram has only negative buckets, the upper bound of the zero
bucket is assumed to be zero.
Furthermore, it makes sure that the zero bucket boundaries are not
modified if a histogram that has no buckets at all but samples in the
zero bucket.
Also, add an TODO to vet if we really want this behavior.
Signed-off-by: beorn7 <beorn@grafana.com>
* 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>
This exactly corresponds to the statistic compared against MaxSamples
during the course of query execution, so users can see how close their
queries are to a limit.
Co-authored-by: Harkishen Singh <harkishensingh@hotmail.com>
Co-authored-by: Andrew Bloomgarden <blmgrdn@amazon.com>
Signed-off-by: Andrew Bloomgarden <blmgrdn@amazon.com>
We always track total samples queried and add those to the standard set
of stats queries can report.
We also allow optionally tracking per-step samples queried. This must be
enabled both at the engine and query level to be tracked and rendered.
The engine flag is exposed via a Prometheus feature flag, while the
query flag is set when stats=all.
Co-authored-by: Alan Protasio <approtas@amazon.com>
Co-authored-by: Andrew Bloomgarden <blmgrdn@amazon.com>
Co-authored-by: Harkishen Singh <harkishensingh@hotmail.com>
Signed-off-by: Andrew Bloomgarden <blmgrdn@amazon.com>
* MergeFloatBucketIterator for []FloatBucketIterator
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
* histogram_quantile for histograms
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
* Fix histogram_quantile
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
* Unit test and enhancements
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
* Iterators to iterate buckets in reverse and all buckets together including zero bucket
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
* Consider all buckets for histogram_quantile and fix the implementation
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
* Remove unneeded code
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
* Fix lint
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
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>
* Add test case to showcase the problem in #9590
Signed-off-by: Thomas Jackson <jacksontj.89@gmail.com>
* Don't unwrap ParenExpr in newStepInvariantExpr
Fixes#9590
Signed-off-by: Thomas Jackson <jacksontj.89@gmail.com>
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>
* promql: copy data when short-circuiting
Because the range query loop re-uses the output buffer each time round,
we must copy results into the buffer rather than using input as output.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* 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>
* 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>
This moves the label lookup into TSDB, whilst still keeping the cached-ref optimisation for repeated Appends.
This makes the API easier to consume and implement. In particular this change is motivated by the scrape-time-aggregation work, which I don't think is possible to implement without it as it needs access to label values.
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
This commit adds `@ <timestamp>` modifier as per this design doc: https://docs.google.com/document/d/1uSbD3T2beM-iX4-Hp7V074bzBRiRNlqUdcWP6JTDQSs/edit.
An example query:
```
rate(process_cpu_seconds_total[1m])
and
topk(7, rate(process_cpu_seconds_total[1h] @ 1234))
```
which ranks based on last 1h rate and w.r.t. unix timestamp 1234 but actually plots the 1m rate.
Signed-off-by: Ganesh Vernekar <cs15btech11018@iith.ac.in>
* Testify: move to require
Moving testify to require to fail tests early in case of errors.
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* More moves
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* Refactor test assertions
This pull request gets rid of assert.True where possible to use
fine-grained assertions.
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* tsdb: Added ChunkQueryable implementations to db; unified compactor, querier and fanout block iterating.
Chained to https://github.com/prometheus/prometheus/pull/7059
* NewMerge(Chunk)Querier now takies multiple primaries allowing tsdb DB code to use it.
* Added single SeriesEntry / ChunkEntry for all series implementations.
* Unified all vertical, and non vertical for compact and querying to single
merge series / chunk sets by reusing VerticalSeriesMergeFunc for overlapping algorithm (same logic as before)
* Added block (Base/Chunk/)Querier for block querying. We then use populateAndTomb(Base/Chunk/) to iterate over chunks or samples.
* Refactored endpoint tests and querier tests to include subtests.
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Addressed comments from Brian and Beorn.
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Fixed snapshot test and added chunk iterator support for DBReadOnly.
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Fixed race when iterating over Ats first.
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Fixed tests.
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Fixed populate block tests.
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Fixed endpoints test.
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Fixed test.
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Added test & fixed case of head open chunk.
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Fixed DBReadOnly tests and bug producing 1 sample chunks.
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Added cases for partial block overlap for multiple full chunks.
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Added extra tests for chunk meta after compaction.
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Fixed small vertical merge bug and added more tests for that.
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Implement go leak test for promql
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* Implement go leak test for Consul SD
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* Implement go leak test in discovery manager
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* promql: Removed global and add ability to have better interval for subqueries if not specified
## Changes
* Refactored tests for better hints testing
* Added various TODO in places to enhance.
* Moved DefaultEvalInterval global to opts with func(rangeMillis int64) int64 function instead
Motivation: At Thanos we would love to have better control over the subqueries step/interval.
This is important to choose proper resolution. I think having proper step also does not harm for
Prometheus and remote read users. Especially on stateless querier we do not know evaluation interval
and in fact putting global can be wrong to assume for Prometheus even.
I think ideally we could try to have at least 3 samples within the range, the same
way Prometheus UI and Grafana assumes.
Anyway this interfaces allows to decide on promQL user basis.
Open question: Is taking parent interval a smart move?
Motivation for removing global: I spent 1h fighting with:
=== RUN TestEvaluations
TestEvaluations: promql_test.go:31: unexpected error: error evaluating query "absent_over_time(rate(nonexistant[5m])[5m:])" (line 687): unexpected error: runtime error: integer divide by zero
--- FAIL: TestEvaluations (0.32s)
FAIL
At the end I found that this fails on most of the versions including this master if you run this test alone. If run together with many
other tests it passes. This is due to SetDefaultEvaluationInterval(1 * time.Minute)
in test that is ran before TestEvaluations. Thanks to globals (:
Let's fix it by dropping this global.
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Added issue links for TODOs.
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Removed irrelevant changes.
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Add errors and Warnings to SeriesSet
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Change Querier interface and refactor accordingly
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Refactor promql/engine to propagate warnings at eval stage
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Address review issues
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Make sure all the series from all Selects are pre-advanced
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Address review issues
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Separate merge series sets
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Clean
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Refactor merge querier failure handling
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Refactored and simplified fanout with improvements from incoming chunk iterator PRs.
* Secondary logic is hidden, instead of weird failed series set logic we had.
* Fanout is well commented
* Fanout closing record all errors
* MergeQuerier improved API (clearer)
* deferredGenericMergeSeriesSet is not needed as we return no samples anyway for failed series sets (next = false).
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Fix formatting
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Fix CI issues
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Added final tests for error handling.
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Addressed Brian's comments.
* Moved hints in populate to be allocated only when needed.
* Used sync.Once in secondary Querier to achieve all-or-nothing partial response logic.
* Select after first Next is done will panic.
NOTE: in lazySeriesSet in theory we could just panic, I think however we can
totally just return error, it will panic in expand anyway.
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Utilize errWithWarnings
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Fix recently introduced expansion issue
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Add tests for secondary querier error handling
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Implement lazy merge
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Add name to test cases
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Reorganize
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Address review comments
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Address review comments
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Remove redundant warnings
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
* Fix rebase mistake
Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>
Co-authored-by: Bartlomiej Plotka <bwplotka@gmail.com>
This is technically BREAKING CHANGE, but it was like this from the beginning: I just notice that we rely in
Prometheus on remote read being sorted. This is because we use selected data from remote reads in MergeSeriesSet
which rely on sorting.
I found during work on https://github.com/prometheus/prometheus/pull/5882 that
we do so many repetitions because of this, for not good reason. I think
I found a good balance between convenience and readability with just one method.
Smaller the interface = better.
Also I don't know what TestSelectSorted was testing, but now it's testing sorting.
Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
* Make lookbackDelta a option of QueryEngine
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* julius' suggestion
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* remove trivial getter
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* Assume lookback delta is always > 0
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* add debug log
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* don't expose loopback delta
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* Specify that lookack delta is also used in federation
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* Fix federation test
While we have added some logic to the promql engine to keep it backwards
compatible and have a 5 minute loopback by default, the web/ package is
likely to really be internal to Prometheus and we should not add the
same kind of heuritstics here.
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* loopback delta: Fix debug log
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
Since we use ActiveQueryTracker to check for concurrency in
d992c36b3a it does not make sense to keep
the MaxConcurrent value as an option of the PromQL engine.
This pull request removes it from the PromQL engine options, sets the
max concurrent metric to -1 if there is no active query tracker, and use
the value of the active query tracker otherwise.
It removes dead code and also will inform people who import the promql
package that we made that change, as it breaks the EngineOpts struct.
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
The windows clock is sometime off by 25ms, and as precise as 15ms.
Let's give it more time to avoid flaky tests.
Fix#6672
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* promql: Move tests to testutil
Signed-off-by: Alex Dzyoba <alex@dzyoba.com>
* promql: Match error type via errors.As in tests
Signed-off-by: Alex Dzyoba <alex@dzyoba.com>
* promql: Remove unused `expectedList` func from lex_test.go
Signed-off-by: Alex Dzyoba <alex@dzyoba.com>
i) Uses the more idiomatic Wrap and Wrapf methods for creating nested errors.
ii) Fixes some incorrect usages of fmt.Errorf where the error messages don't have any formatting directives.
iii) Does away with the use of fmt package for errors in favour of pkg/errors
Signed-off-by: tariqibrahim <tariq181290@gmail.com>
Since it is used in a type assertion, having it as an alias to the
error interface is the same as saying 'error', i.e. it succeeds for
all types of error. Change to a struct which is a concrete type and
the type assertion will only succeed if the type is identical.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
This adds a parameter to the storage selection interface which allows
query engine(s) to pass information about the operations surrounding a
data selection.
This can for example be used by remote storage backends to infer the
correct downsampling aggregates that need to be provided.
* Re-add contexts to storage.Storage.Querier()
These are needed when replacing the storage by a multi-tenant
implementation where the tenant is stored in the context.
The 1.x query interfaces already had contexts, but they got lost in 2.x.
* Convert promql.Engine to use native contexts
* Fix error where we look into the future.
So currently we are adding values that are in the future for an older
timestamp. For example, if we have [(1, 1), (150, 2)] we will end up
showing [(1, 1), (2,2)].
Further it is not advisable to call .At() after Next() returns false.
Signed-off-by: Goutham Veeramachaneni <cs14btech11014@iith.ac.in>
* Retuen early if done
Signed-off-by: Goutham Veeramachaneni <cs14btech11014@iith.ac.in>
* Handle Seek() where we reach the end of iterator
Signed-off-by: Goutham Veeramachaneni <cs14btech11014@iith.ac.in>
* Simplify code
Signed-off-by: Goutham Veeramachaneni <cs14btech11014@iith.ac.in>
Query and query_range should return the timestamp
at which an evaluation is performed, not the timestamp
of the data. This is as that's what query range asked
for, and we need to keep query consistent with that.
Query for a matrix remains unchanged, returning the literal
matrix.
This is based on https://github.com/prometheus/prometheus/pull/1997.
This adds contexts to the relevant Storage methods and already passes
PromQL's new per-query context into the storage's query methods.
The immediate motivation supporting multi-tenancy in Frankenstein, but
this could also be used by Prometheus's normal local storage to support
cancellations and timeouts at some point.
For Weaveworks' Frankenstein, we need to support multitenancy. In
Frankenstein, we initially solved this without modifying the promql
package at all: we constructed a new promql.Engine for every
query and injected a storage implementation into that engine which would
be primed to only collect data for a given user.
This is problematic to upstream, however. Prometheus assumes that there
is only one engine: the query concurrency gate is part of the engine,
and the engine contains one central cancellable context to shut down all
queries. Also, creating a new engine for every query seems like overkill.
Thus, we want to be able to pass per-query contexts into a single engine.
This change gets rid of the promql.Engine's built-in base context and
allows passing in a per-query context instead. Central cancellation of
all queries is still possible by deriving all passed-in contexts from
one central one, but this is now the responsibility of the caller. The
central query context is now created in main() and passed into the
relevant components (web handler / API, rule manager).
In a next step, the per-query context would have to be passed to the
storage implementation, so that the storage can implement multi-tenancy
or other features based on the contextual information.
See discussion in
https://groups.google.com/forum/#!topic/prometheus-developers/bkuGbVlvQ9g
The main idea is that the user of a storage shouldn't have to deal with
fingerprints anymore, and should not need to do an individual preload
call for each metric. The storage interface needs to be made more
high-level to not expose these details.
This also makes it easier to reuse the same storage interface for remote
storages later, as fewer roundtrips are required and the fingerprint
concept doesn't work well across the network.
NOTE: this deliberately gets rid of a small optimization in the old
query Analyzer, where we dedupe instants and ranges for the same series.
This should have a minor impact, as most queries do not have multiple
selectors loading the same series (and at the same offset).
Prometheus is Apache 2 licensed, and most source files have the
appropriate copyright license header, but some were missing it without
apparent reason. Correct that by adding it.
This commit removes the possibility to have multi-statement queries
which had no full support anyway. This makes the caller responsible
for multi-statement semantics.
Multiple tests are no longer timing-dependent.
A high number of concurrent queries can slow each other down
so that none of them is reasonbly responsive. This commit limits
the number of queries being concurrently executed.
This copies the evaluation logic from the current rules/ package.
The new engine handles the execution process from query string to final result.
It provides query timeout and cancellation and general flexibility for
future changes.
functions.go: Add evaluation implementation. Slight changes to in/out data but
not to the processing logic.
quantile.go: No changes.
analyzer.go: No changes.
engine.go: Actually new part. Mainly consists of evaluation methods
which were not changed.
setup_test.go: Copy of rules/helpers_test.go to setup test storage.
promql_test.go: Copy of rules/rules_test.go.
