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>
`getOOOSeriesChunks` was already finding sets of overlapping chunks; we
store those in a `multiMeta` struct so that `ChunkOrIterable` can
reconstruct an `Iterable` easily and predictably.
We no longer need a `MergeOOO` flag to indicate that this Meta should
be merged with other ones; this is explicit in the `multiMeta` structure.
We also no longer need `chunkMetaAndChunkDiskMapperRef`.
Add `wrapOOOHeadChunk` to defeat `chunkenc.Pool` - chunks are reset
during compaction, but if we wrap them (like `safeHeadChunk` was doing
then this is skipped) .
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
fix(utf8): ensure correct validation when legacy mode turned on
This depends on the included update of the prometheus/common dependency.
---------
Signed-off-by: Owen Williams <owen.williams@grafana.com>
Case 1: OOO in-memory head chunk overlaps with first mmaped in-order chunk.
Query: |----------------------------------------------------------------|
InO: |------mmap---------------||---------mem----------------------|
OOO: |-----mem-----------|
This triggers ChunkOrIterableWithCopy not including OOO head chunks bug.
Similar to #14693 however testing the end of the interval doesn't
trigger the problem because there the in-order head chunk will be
trimmed with a tombstone, causing the code to switch to ChunkOrIterable
which was fixed.
See a36d1a8a92/tsdb/querier.go (L646)
where len(p.bufIter.Intervals) will be non zero, because it includes the
tombstone to trim the result to the query max time.
Thus a new test is added to check the overlap at the beginning of the
interval that has a separate chunk, which does not need trimming.
Note: same test doesn't fail for sample querier in Test_Querier_OOOQuery
as that doesn't use copy, that is copyHeadChunk is false in the if
condition above.
Case 2:
OOO mmaped head chunk overlaps with first mmaped in-order chunk.
Query: |----------------------------------------------------------------|
InO: |------mmap---------------||---------mem----------------------|
OOO: |-----mmap-----------| |--mem--|
In this case the meta contains the reference of the in-order chunk and
no indication that a merge is needed with the OOO mmaped chunk.
Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>
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>
* tsdb: Unit test query overlapping in order and ooo head
Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>
* TSDB: Merge overlapping head chunk
The basic idea is that getOOOSeriesChunks can populate Meta.Chunk, but since
it only returns one Meta per overlapping time-slot, that pointer may end up in a
Meta with a head-chunk ID. So we need HeadAndOOOChunkReader.ChunkOrIterable()
to call mergedChunks in that case.
Previously, mergedChunks was checking that meta.Ref was a valid OOO chunk reference,
but it never actually uses that reference; it just finds all chunks overlapping in time.
So we can delete that code.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Co-authored-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>
Use `openssl x509 -text -in <file>` to include the text version of the
certificate in order to make it easier to see the diff when applying
changes to the cert.
Signed-off-by: SuperQ <superq@gmail.com>
Jorge Creixell