Rather than keeping the entire symbol table in memory, keep every nth
offset and walk from there to the entry we need. This ends up slightly
slower, ~360ms per 1M series returned from PostingsForMatchers which is
not much considering the rest of the CPU such a query would go on to
use.
Make LabelValues use the postings tables, rather than having
to do symbol lookups. Use yoloString, as PostingsForMatchers
doesn't need the strings to stick around and adjust the API
call to keep the Querier open until it's all marshalled.
Remove allocatedSymbols memory optimisation, we no longer keep all the
symbol strings in heap memory. Remove LabelValuesFor and LabelIndices,
they're dead code. Ensure we've still tests for label indices,
and add missing test that we can work with old V1 Format index files.
PostingForMatchers performance is slightly better, with a big drop in
allocation counts due to using yoloString for LabelValues:
benchmark old ns/op new ns/op delta
BenchmarkPostingsForMatchers/Block/n="1"-4 36698 36681 -0.05%
BenchmarkPostingsForMatchers/Block/n="1",j="foo"-4 522786 560887 +7.29%
BenchmarkPostingsForMatchers/Block/j="foo",n="1"-4 511652 537680 +5.09%
BenchmarkPostingsForMatchers/Block/n="1",j!="foo"-4 522102 564239 +8.07%
BenchmarkPostingsForMatchers/Block/i=~".*"-4 113689911 111795919 -1.67%
BenchmarkPostingsForMatchers/Block/i=~".+"-4 135825572 132871085 -2.18%
BenchmarkPostingsForMatchers/Block/i=~""-4 40782628 38038181 -6.73%
BenchmarkPostingsForMatchers/Block/i!=""-4 31267869 29194327 -6.63%
BenchmarkPostingsForMatchers/Block/n="1",i=~".*",j="foo"-4 112733329 111568823 -1.03%
BenchmarkPostingsForMatchers/Block/n="1",i=~".*",i!="2",j="foo"-4 112868153 111232029 -1.45%
BenchmarkPostingsForMatchers/Block/n="1",i!=""-4 31338257 29349446 -6.35%
BenchmarkPostingsForMatchers/Block/n="1",i!="",j="foo"-4 32054482 29972436 -6.50%
BenchmarkPostingsForMatchers/Block/n="1",i=~".+",j="foo"-4 136504654 133968442 -1.86%
BenchmarkPostingsForMatchers/Block/n="1",i=~"1.+",j="foo"-4 27960350 27264997 -2.49%
BenchmarkPostingsForMatchers/Block/n="1",i=~".+",i!="2",j="foo"-4 136765564 133860724 -2.12%
BenchmarkPostingsForMatchers/Block/n="1",i=~".+",i!~"2.*",j="foo"-4 163714583 159453668 -2.60%
benchmark old allocs new allocs delta
BenchmarkPostingsForMatchers/Block/n="1"-4 6 6 +0.00%
BenchmarkPostingsForMatchers/Block/n="1",j="foo"-4 11 11 +0.00%
BenchmarkPostingsForMatchers/Block/j="foo",n="1"-4 11 11 +0.00%
BenchmarkPostingsForMatchers/Block/n="1",j!="foo"-4 17 15 -11.76%
BenchmarkPostingsForMatchers/Block/i=~".*"-4 100012 12 -99.99%
BenchmarkPostingsForMatchers/Block/i=~".+"-4 200040 100040 -49.99%
BenchmarkPostingsForMatchers/Block/i=~""-4 200045 100045 -49.99%
BenchmarkPostingsForMatchers/Block/i!=""-4 200041 100041 -49.99%
BenchmarkPostingsForMatchers/Block/n="1",i=~".*",j="foo"-4 100017 17 -99.98%
BenchmarkPostingsForMatchers/Block/n="1",i=~".*",i!="2",j="foo"-4 100023 23 -99.98%
BenchmarkPostingsForMatchers/Block/n="1",i!=""-4 200046 100046 -49.99%
BenchmarkPostingsForMatchers/Block/n="1",i!="",j="foo"-4 200050 100050 -49.99%
BenchmarkPostingsForMatchers/Block/n="1",i=~".+",j="foo"-4 200049 100049 -49.99%
BenchmarkPostingsForMatchers/Block/n="1",i=~"1.+",j="foo"-4 111150 11150 -89.97%
BenchmarkPostingsForMatchers/Block/n="1",i=~".+",i!="2",j="foo"-4 200055 100055 -49.99%
BenchmarkPostingsForMatchers/Block/n="1",i=~".+",i!~"2.*",j="foo"-4 311238 111238 -64.26%
benchmark old bytes new bytes delta
BenchmarkPostingsForMatchers/Block/n="1"-4 296 296 +0.00%
BenchmarkPostingsForMatchers/Block/n="1",j="foo"-4 424 424 +0.00%
BenchmarkPostingsForMatchers/Block/j="foo",n="1"-4 424 424 +0.00%
BenchmarkPostingsForMatchers/Block/n="1",j!="foo"-4 552 1544 +179.71%
BenchmarkPostingsForMatchers/Block/i=~".*"-4 1600482 1606125 +0.35%
BenchmarkPostingsForMatchers/Block/i=~".+"-4 17259065 17264709 +0.03%
BenchmarkPostingsForMatchers/Block/i=~""-4 17259150 17264780 +0.03%
BenchmarkPostingsForMatchers/Block/i!=""-4 17259048 17264680 +0.03%
BenchmarkPostingsForMatchers/Block/n="1",i=~".*",j="foo"-4 1600610 1606242 +0.35%
BenchmarkPostingsForMatchers/Block/n="1",i=~".*",i!="2",j="foo"-4 1600813 1606434 +0.35%
BenchmarkPostingsForMatchers/Block/n="1",i!=""-4 17259176 17264808 +0.03%
BenchmarkPostingsForMatchers/Block/n="1",i!="",j="foo"-4 17259304 17264936 +0.03%
BenchmarkPostingsForMatchers/Block/n="1",i=~".+",j="foo"-4 17259333 17264965 +0.03%
BenchmarkPostingsForMatchers/Block/n="1",i=~"1.+",j="foo"-4 3142628 3148262 +0.18%
BenchmarkPostingsForMatchers/Block/n="1",i=~".+",i!="2",j="foo"-4 17259509 17265141 +0.03%
BenchmarkPostingsForMatchers/Block/n="1",i=~".+",i!~"2.*",j="foo"-4 20405680 20416944 +0.06%
However overall Select performance is down and involves more allocs, due to
having to do more than a simple map lookup to resolve a symbol and that all the strings
returned are allocated:
benchmark old ns/op new ns/op delta
BenchmarkQuerierSelect/Block/1of1000000-4 506092636 862678244 +70.46%
BenchmarkQuerierSelect/Block/10of1000000-4 505638968 860917636 +70.26%
BenchmarkQuerierSelect/Block/100of1000000-4 505229450 882150048 +74.60%
BenchmarkQuerierSelect/Block/1000of1000000-4 515905414 862241115 +67.13%
BenchmarkQuerierSelect/Block/10000of1000000-4 516785354 874841110 +69.29%
BenchmarkQuerierSelect/Block/100000of1000000-4 540742808 907030187 +67.74%
BenchmarkQuerierSelect/Block/1000000of1000000-4 815224288 1181236903 +44.90%
benchmark old allocs new allocs delta
BenchmarkQuerierSelect/Block/1of1000000-4 4000020 6000020 +50.00%
BenchmarkQuerierSelect/Block/10of1000000-4 4000038 6000038 +50.00%
BenchmarkQuerierSelect/Block/100of1000000-4 4000218 6000218 +50.00%
BenchmarkQuerierSelect/Block/1000of1000000-4 4002018 6002018 +49.97%
BenchmarkQuerierSelect/Block/10000of1000000-4 4020018 6020018 +49.75%
BenchmarkQuerierSelect/Block/100000of1000000-4 4200018 6200018 +47.62%
BenchmarkQuerierSelect/Block/1000000of1000000-4 6000018 8000019 +33.33%
benchmark old bytes new bytes delta
BenchmarkQuerierSelect/Block/1of1000000-4 176001468 227201476 +29.09%
BenchmarkQuerierSelect/Block/10of1000000-4 176002620 227202628 +29.09%
BenchmarkQuerierSelect/Block/100of1000000-4 176014140 227214148 +29.09%
BenchmarkQuerierSelect/Block/1000of1000000-4 176129340 227329348 +29.07%
BenchmarkQuerierSelect/Block/10000of1000000-4 177281340 228481348 +28.88%
BenchmarkQuerierSelect/Block/100000of1000000-4 188801340 240001348 +27.12%
BenchmarkQuerierSelect/Block/1000000of1000000-4 304001340 355201616 +16.84%
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
This adds support for a new query param on the new `api/v1/metadata`
endpoint that provides metadata for a specified metric via the V1 API.
It collapses metadata that is equal across all targets, and aggregates
under the same metric name the ones that differ.
Signed-off-by: gotjosh <josue@grafana.com>
* api: provide per metric metadata
This adds a new endpoint that provides per metric metadata via the V1 API.
It collapses metadata that is equal across all targets, and aggregates under the same metric name the ones that differ.
* Allow tests to be asserted on response length
Some tests e.g. limit on API responses, don't require an assertion on
equality.
This allows us to assert against response length instead of
equality.
Signed-off-by: gotjosh <josue@grafana.com>
According to the documentation, the target metadata API accepts it,
if no value for match_target has been provided. This was not the case
in the implementation.
This commit make the API behave as described in the docs.
Signed-off-by: Tobias Guggenmos <tguggenm@redhat.com>
* Add tests to ensure we can marshal and unmarshal our min/max times
Related to https://github.com/prometheus/client_golang/issues/614
Instead of implementing all the time parsing, we can special-case handle
these 2 times. This means if times in this format show up that
time.Parse can't handle they will still error, but we can marshal/parse
our own min/max time
Signed-off-by: Thomas Jackson <jacksontj.89@gmail.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>
- Unmarshall external_labels config as labels.Labels, add tests.
- Convert some more uses of model.LabelSet to labels.Labels.
- Remove old relabel pkg (fixes#3647).
- Validate external label names.
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
* *: use latest release of staticcheck
It also fixes a couple of things in the code flagged by the additional
checks.
Signed-off-by: Simon Pasquier <spasquie@redhat.com>
* Use official release of staticcheck
Also run 'go list' before staticcheck to avoid failures when downloading packages.
Signed-off-by: Simon Pasquier <spasquie@redhat.com>
The scrape manage receiver's channel now just saves the target sets
and another backgorund runner updates the scrape loops every 5 seconds.
This is so that the scrape manager doesn't block the receiving channel
when it does the long background reloading of the scrape loops.
Active and dropped targets are now saved in each scrape pool instead of
the scrape manager. This is mainly to avoid races when getting the
targets via the web api.
When reloading the scrape loops now happens in parallel to speed up the
final disared state and this also speeds up the prometheus's shutting
down.
Also updated some funcs signatures in the web package for consistency.
Signed-off-by: Krasi Georgiev <kgeorgie@redhat.com>
* Limit the number of samples remote read can return.
- Return 413 entity too large.
- Limit can be set be a flag. Allow 0 to mean no limit.
- Include limit in error message.
- Set default limit to 50M (* 16 bytes = 800MB).
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
There are many more (mostly finalizers like Close/Stop/etc.), but most of
the others seemed like one couldn't do much about them anyway.
Signed-off-by: Julius Volz <julius.volz@gmail.com>
* Add Start/End to SelectParams
* Make remote read use the new selectParams for start/end
This commit will continue sending the start/end time of the remote read
query as the overarching promql time and the specific range of data that
the query is intersted in receiving a response to is now part of the
ReadHints (upstream discussion in #4226).
* Remove unused vendored code
The genproto.sh script was updated, but the code wasn't regenerated.
This simply removes the vendored deps that are no longer part of the
codegen output.
Signed-off-by: Thomas Jackson <jacksontj.89@gmail.com>
This adds a per-target cache of scraped metadata. The metadata is only
available for the lifecycle of the attached target. An API endpoint allows
to select metadata by metric name and a label selection of targets.
Signed-off-by: Fabian Reinartz <freinartz@google.com>
* Move range logic to 'eval'
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Make aggregegate range aware
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* PromQL is statically typed, so don't eval to find the type.
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Extend rangewrapper to multiple exprs
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Start making function evaluation ranged
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Make instant queries a special case of range queries
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Eliminate evalString
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Evaluate range vector functions one series at a time
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Make unary operators range aware
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Make binops range aware
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Pass time to range-aware functions.
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Make simple _over_time functions range aware
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Reduce allocs when working with matrix selectors
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Add basic benchmark for range evaluation
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Reuse objects for function arguments
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Do dropmetricname and allocating output vector only once.
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Add range-aware support for range vector functions with params
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Optimise holt_winters, cut cpu and allocs by ~25%
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Make rate&friends range aware
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Make more functions range aware. Document calling convention.
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Make date functions range aware
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Make simple math functions range aware
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Convert more functions to be range aware
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Make more functions range aware
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Specialcase timestamp() with vector selector arg for range awareness
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Remove transition code for functions
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Remove the rest of the engine transition code
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Remove more obselete code
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Remove the last uses of the eval* functions
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Remove engine finalizers to prevent corruption
The finalizers set by matrixSelector were being called
just before the value they were retruning to the pool
was then being provided to the caller. Thus a concurrent query
could corrupt the data that the user has just been returned.
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Add new benchmark suite for range functinos
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Migrate existing benchmarks to new system
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Expand promql benchmarks
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Simply test by removing unused range code
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* When testing instant queries, check range queries too.
To protect against subsequent steps in a range query being
affected by the previous steps, add a test that evaluates
an instant query that we know works again as a range query
with the tiimestamp we care about not being the first step.
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Reuse ring for matrix iters. Put query results back in pool.
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Reuse buffer when iterating over matrix selectors
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Unary minus should remove metric name
Cut down benchmarks for faster runs.
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Reduce repetition in benchmark test cases
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Work series by series when doing normal vectorSelectors
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Optimise benchmark setup, cuts time by 60%
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Have rangeWrapper use an evalNodeHelper to cache across steps
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Use evalNodeHelper with functions
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Cache dropMetricName within a node evaluation.
This saves both the calculations and allocs done by dropMetricName
across steps.
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Reuse input vectors in rangewrapper
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Reuse the point slices in the matrixes input/output by rangeWrapper
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Make benchmark setup faster using AddFast
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Simplify benchmark code.
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Add caching in VectorBinop
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Use xor to have one-level resultMetric hash key
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Add more benchmarks
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Call Query.Close in apiv1
This allows point slices allocated for the response data
to be reused by later queries, saving allocations.
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Optimise histogram_quantile
It's now 5-10% faster with 97% less garbage generated for 1k steps
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Make the input collection in rangeVector linear rather than quadratic
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Optimise label_replace, for 1k steps 15x fewer allocs and 3x faster
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Optimise label_join, 1.8x faster and 11x less memory for 1k steps
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Expand benchmarks, cleanup comments, simplify numSteps logic.
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Address Fabian's comments
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Comments from Alin.
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Address jrv's comments
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Remove dead code
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Address Simon's comments.
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Rename populateIterators, pre-init some sizes
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Handle case where function has non-matrix args first
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Split rangeWrapper out to rangeEval function, improve comments
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Cleanup and make things more consistent
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Make EvalNodeHelper public
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
* Fabian's comments.
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
Fix race by properly locking access to scrape pools. Use separate mutex for information needed by UI so that UI isn't blocked when targets are being updated.
* web: replace deprecated InstrumentHandler()
This change replaces the deprecated InstrumentHandler function by the
equivalent functions from the promhttp package.
The following metrics are removed:
* http_request_duration_microseconds (Summary).
* http_request_size_bytes (Summary).
* http_requests_total (Counter).
And the following metrics are added instead:
* prometheus_http_request_duration_seconds (Histogram).
* prometheus_http_response_size_bytes (Histogram).
* promhttp_metric_handler_requests_in_flight (Gauge).
* promhttp_metric_handler_requests_total (Counter).
* Update github.com/prometheus/common/route package
* web: refactor using the new prometheus/common/route package
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.
Federation makes use of dedupedSeriesSet to merge SeriesSets for every
query into one output stream. If many match[] arguments are provided,
many dedupedSeriesSet objects will get chained. This has the downside of
causing a potential O(n*k) running time, where n is the number of series
and k the number of match[] arguments.
In the mean time, the storage package provides a mergeSeriesSet that
accomplishes the same with an O(n*log(k)) running time by making use of
a binary heap. Let's just get rid of dedupedSeriesSet and change all
existing callers to use mergeSeriesSet.
API consumers should be able to get insight into the query run times.
The UI currently measures total roundtrip times. This PR allows for more
fine grained metrics to be exposed.
* adds new timer for total execution time (queue + eval)
* expose new timer, queue timer, and eval timer in stats field of the
range query response:
```json
{
"status": "success",
"data": {
"resultType": "matrix",
"result": [],
"stats": {
"execQueueTimeNs": 4683,
"execTotalTimeNs": 2086587,
"totalEvalTimeNs": 2077851
}
}
}
```
* stats field is optional, only set when query parameter `stats` is not
empty
Try it via
```sh
curl 'http://localhost:9090/api/v1/query_range?query=up&start=1486480279&end=1486483879&step=14000&stats=true'
```
Review feedback
* moved query stats json generation to query_stats.go
* use seconds for all query timers
* expose all timers available
* Changed ExecTotalTime string representation from Exec queue total time to Exec total time
This PR fixes#3072 by providing POST endpoints for `query` and `query_range`.
POST request must be made with `Content-Type: application/x-www-form-urlencoded` header.
* 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
This PR adds the `/status/config` endpoint which exposes the currently
loaded Prometheus config. This is the same config that is displayed on
`/config` in the UI in YAML format. The response payload looks like
such:
```
{
"status": "success",
"data": {
"yaml": <CONFIG>
}
}
```
* Use request.Context() instead of a global map of contexts.
* Add some basic opentracing instrumentation on the query path.
* Remove tracehandler endpoint.
* Fixed int64 overflow for timestamp in v1/api parseDuration and parseTime
This led to unexpected results on wrong query with "(...)&start=148966367200.372&end=1489667272.372"
That query is wrong because of `start > end` but actually internal int64 overflow caused start to be something around MinInt64 (huge negative value) and was passing validation.
BTW: Not sure if negative timestamp makes sense even.. But model.Earliest is actually MinInt64, can someone explain me why?
Signed-off-by: Bartek Plotka <bwplotka@gmail.com>
* Added missing trailing periods on comments.
Signed-off-by: Bartek Plotka <bwplotka@gmail.com>
* MOved to only `<` and `>`. Removed equal.
Signed-off-by: Bartek Plotka <bwplotka@gmail.com>
retreival.Target contains a mutex. It was copied in the Targets()
call. This potentially can wreak a lot of havoc.
It might even have caused the issues reported as #2266 and #2262 .
This extracts Querier as an instantiateable and closeable object
rather than just defining extending methods of the storage interface.
This improves composability and allows abstracting query transactions,
which can be useful for transaction-level caches, consistent data views,
and encapsulating teardown.
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.
WIP: This needs more tests.
It now gets a from and through value, which it may opportunistically
use to optimize the retrieval. With possible future range indices,
this could be used in a very efficient way. This change merely applies
some easy checks, which should nevertheless solve the use case of
heavy rule evaluations on servers with a lot of series churn.
Idea is the following:
- Only archive series that are at least as old as the headChunkTimeout
(which was already extremely unlikely to happen).
- Then maintain a high watermark for the last archival, i.e. no
archived series has a sample more recent than that watermark.
- Any query that doesn't reach to a time before that watermark doesn't
have to touch the archive index at all. (A production server at
Soundcloud with the aforementioned series churn and heavy rule
evaluations spends 50% of its CPU time in archive index
lookups. Since rule evaluations usually only touch very recent
values, most of those lookup should disappear with this change.)
- Federation with a very broad label matcher will profit from this,
too.
As a byproduct, the un-needed MetricForFingerprint method was removed
from the Storage interface.
It's actually happening in several places (and for flags, we use the
standard Go time.Duration...). This at least reduces all our
home-grown parsing to one place (in model).
Julien Pivotto