The `info` function is an experiment to improve UX
around including labels from info metrics.
`info` has to be enabled via the feature flag `--enable-feature=promql-experimental-functions`.
This MVP of info simplifies the implementation by assuming:
* Only support for the target_info metric
* That target_info's identifying labels are job and instance
Also:
* Encode info samples' original timestamp as sample value
* Deduce info series select hints from top-most VectorSelector
---------
Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>
Co-authored-by: Ying WANG <ying.wang@grafana.com>
Co-authored-by: Augustin Husson <augustin.husson@amadeus.com>
Co-authored-by: Bartlomiej Plotka <bwplotka@gmail.com>
Co-authored-by: Björn Rabenstein <github@rabenste.in>
Co-authored-by: Bryan Boreham <bjboreham@gmail.com>
promql: correctly handle unary negation of native histograms and add tests for multiplication and division of native histograms by negative scalars
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
For aggregates, operators, calls, show what operation is performed.
Also add an event when series are expanded, typically time spent
accessing TSDB.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
PromQL engine: Delay deletion of __name__ label to the end of the query evaluation
- This change allows optionally preserving the `__name__` label via the `label_replace` and `label_join` functions, and helps prevent the dreaded "vector cannot contain metrics with the same labelset" error.
- The implementation extends the `Series` and `Sample` structs with a boolean flag indicating whether the `__name__` label should be deleted at the end of the query evaluation.
- The `label_replace` and `label_join` functions can still access the value of the `__name__` label, even if it has been previously marked for deletion. If `__name__` is used as target label, it won't be dropped at the end of the query evaluation.
- Fixes https://github.com/prometheus/prometheus/issues/11397
- See https://github.com/jcreixell/prometheus/pull/2 for previous discussion, including the decision to create this PR and benchmark it before considering other alternatives (like refactoring `labels.Labels`).
- See https://github.com/jcreixell/prometheus/pull/1 for an alternative implementation using a special label instead of boolean flags.
- Note: a feature flag `promql-delayed-name-removal` has been added as it changes the behavior of some "weird" queries (see https://github.com/prometheus/prometheus/issues/11397#issuecomment-1451998792)
Example (this always fails, as `__name__` is being dropped by `count_over_time`):
```
count_over_time({__name__!=""}[1m])
=> Error executing query: vector cannot contain metrics with the same labelset
```
Before:
```
label_replace(count_over_time({__name__!=""}[1m]), "__name__", "count_$1", "__name__", "(.+)")
=> Error executing query: vector cannot contain metrics with the same labelset
```
After:
```
label_replace(count_over_time({__name__!=""}[1m]), "__name__", "count_$1", "__name__", "(.+)")
=>
count_go_gc_cycles_automatic_gc_cycles_total{instance="localhost:9090", job="prometheus"} 1
count_go_gc_cycles_forced_gc_cycles_total{instance="localhost:9090", job="prometheus"} 1
...
```
Signed-off-by: Jorge Creixell <jcreixell@gmail.com>
---------
Signed-off-by: Jorge Creixell <jcreixell@gmail.com>
Signed-off-by: Björn Rabenstein <github@rabenste.in>
Several things done here:
- Set `max-issues-per-linter` to 0 so that we actually see all linter
warnings and not just 50 per linter. (As we also set
`max-same-issues` to 0, I assume this was the intention from the
beginning.)
- Stop using the golangci-lint default excludes (by setting
`exclude-use-default: false`. Those are too generous and don't match
our style conventions. (I have re-added some of the excludes
explicitly in this commit. See below.)
- Re-add the `errcheck` exclusion we have used so far via the
defaults.
- Exclude the signature requirement `govet` has for `Seek` methods
because we use non-standard `Seek` methods a lot. (But we keep other
requirements, while the default excludes completely disabled the
check for common method segnatures.)
- Exclude warnings about missing doc comments on exported symbols. (We
used to be pretty adamant about doc comments, but stopped that at
some point in the past. By now, we have about 500 missing doc
comments. We may consider reintroducing this check, but that's
outside of the scope of this commit. The default excludes of
golangci-lint essentially ignore doc comments completely.)
- By stop using the default excludes, we now get warnings back on
malformed doc comments. That's the most impactful change in this
commit. It does not enforce doc comments (again), but _if_ there is
a doc comment, it has to have the recommended form. (Most of the
changes in this commit are fixing this form.)
- Improve wording/spelling of some comments in .golangci.yml, and
remove an outdated comment.
- Leave `package-comments` inactive, but add a TODO asking if we
should change that.
- Add a new sub-linter `comment-spacings` (and fix corresponding
comments), which avoids missing spaces after the leading `//`.
Signed-off-by: beorn7 <beorn@grafana.com>
chunkenc.Iterator.AtFloatHistogram may do a shallow copy if
it receives nil as input pointer. This can in turn share the
span slice with multiple histograms in the matrixSelectorHPool,
leading to unexpected errors.
Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>
The basic idea here is that the previous code was always doing
incremental calculation of the mean value, which is more costly and
can be less precise. It protects against overflows, but in most cases,
an overflow doesn't happen anyway.
The other idea applied here is to expand on #14074, where Kahan
summation was applied to sum().
With this commit, the average is calculated in a conventional way
(adding everything up and divide in the end) as long as the sum isn't
overflowing float64. This is combined with Kahan summation so that the
avg aggregation, in most cases, is really equivalent to the sum
aggregation with a following division (which is the user's expectation
as avg is supposed to be syntactic sugar for sum with a following
divison).
If the sum hits ±Inf, the calculation reverts to incremental
calculation of the mean value. Kahan summation is also applied here,
although it cannot fully compensate for the numerical errors
introduced by the incremental mean calculation. (The tests added in
this commit would fail if incremental mean calculation was always
used.)
Signed-off-by: beorn7 <beorn@grafana.com>
The optimizer which detects cases where histogram buckets can be skipped
does not take into account binary expressions. This can lead to buckets
not being decoded if a metric is used with both histogram_fraction/quantile and
histogram_sum/count in the same expression.
Signed-off-by: Filip Petkovski <filip.petkovsky@gmail.com>
Implement histogram statistics decoder
This commit speeds up histogram_count and histogram_sum
functions on native histograms. The idea is to have separate decoders which can be
used by the engine to only read count/sum values from histogram objects. This should help
with reducing allocations when decoding histograms, as well as with speeding up aggregations
like sum since they will be done on floats and not on histogram objects.
Signed-off-by: Filip Petkovski <filip.petkovsky@gmail.com>
---------
Signed-off-by: Filip Petkovski <filip.petkovsky@gmail.com>
Co-authored-by: Anthony Mirabella <a9@aneurysm9.com>
This can give a more precise result, by keeping a separate running
compensation value to accumulate small errors.
See https://en.wikipedia.org/wiki/Kahan_summation_algorithm
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
The function `rangeEvalTimestampFunctionOverVectorSelector` appeared to be checking histogram size, however the value it used was always 0 due to subtle variable shadowing.
However we don't need to pass sample values to the `timestamp` function, since the latter only cares about timestamps. This also affects peak sample count in statistics, since we are no longer copying histogram samples.
Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>
Arve Knudsen