Wiser coders than myself have come to the conclusion that a `switch`
statement is almost always superior to a statement that includes any
`else if`.
The exceptions that I have found in our codebase are just these two:
* The `if else` is followed by an additional statement before the next
condition (separated by a `;`).
* The whole thing is within a `for` loop and `break` statements are
used. In this case, using `switch` would require tagging the `for`
loop, which probably tips the balance.
Why are `switch` statements more readable?
For one, fewer curly braces. But more importantly, the conditions all
have the same alignment, so the whole thing follows the natural flow
of going down a list of conditions. With `else if`, in contrast, all
conditions but the first are "hidden" behind `} else if `, harder to
spot and (for no good reason) presented differently from the first
condition.
I'm sure the aforemention wise coders can list even more reasons.
In any case, I like it so much that I have found myself recommending
it in code reviews. I would like to make it a habit in our code base,
without making it a hard requirement that we would test on the CI. But
for that, there has to be a role model, so this commit eliminates all
`if else` occurrences, unless it is autogenerated code or fits one of
the exceptions above.
Signed-off-by: beorn7 <beorn@grafana.com>
We haven't updated golint-ci in our CI yet, but this commit prepares
for that.
There are a lot of new warnings, and it is mostly because the "revive"
linter got updated. I agree with most of the new warnings, mostly
around not naming unused function parameters (although it is justified
in some cases for documentation purposes – while things like mocks are
a good example where not naming the parameter is clearer).
I'm pretty upset about the "empty block" warning to include `for`
loops. It's such a common pattern to do something in the head of the
`for` loop and then have an empty block. There is still an open issue
about this: https://github.com/mgechev/revive/issues/810 I have
disabled "revive" altogether in files where empty blocks are used
excessively, and I have made the effort to add individual
`// nolint:revive` where empty blocks are used just once or twice.
It's borderline noisy, though, but let's go with it for now.
I should mention that none of the "empty block" warnings for `for`
loop bodies were legitimate.
Signed-off-by: beorn7 <beorn@grafana.com>
* Limit FastRegexMatcher by size (bytes) and add a TTL to each entry
Signed-off-by: Marco Pracucci <marco@pracucci.com>
* Add TestNewFastRegexMatcher_CacheSizeLimit
Signed-off-by: Marco Pracucci <marco@pracucci.com>
* Tolerate ristretto goroutines when checking goroutine leaks
Signed-off-by: Marco Pracucci <marco@pracucci.com>
* Tolerate ristretto goroutines when checking goroutine leaks
Signed-off-by: Marco Pracucci <marco@pracucci.com>
---------
Signed-off-by: Marco Pracucci <marco@pracucci.com>
In the past, every sample value was a float, so it was fine to call a
variable holding such a float "value" or "sample". With native
histograms, a sample might have a histogram value. And a histogram
value is still a value. Calling a float value just "value" or "sample"
or "V" is therefore misleading. Over the last few commits, I already
renamed many variables, but this cleans up a few more places where the
changes are more invasive.
Note that we do not to attempt naming in the JSON APIs or in the
protobufs. That would be quite a disruption. However, internally, we
can call variables as we want, and we should go with the option of
avoiding misunderstandings.
Signed-off-by: beorn7 <beorn@grafana.com>
Previously, we had one “polymorphous” `sample` type in the `storage`
package. This commit breaks it up into `fSample`, `hSample`, and
`fhSample`, each still implementing the `tsdbutil.Sample` interface.
This reduces allocations in `sampleRing.Add` but inflicts the penalty
of the interface wrapper, which makes things worse in total.
This commit therefore just demonstrates the step taken. The next
commit will tackle the interface overhead problem.
Signed-off-by: beorn7 <beorn@grafana.com>
It seems that readOnlyDB was still opened which blocked the temp dir
cleanup.
Also changed the copy dir to be another TempDir instead of manually
creating one.
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
* Use zeropool.Pool to workaround SA6002
I built a tiny library called https://github.com/colega/zeropool to
workaround the SA6002 staticheck issue.
While searching for the references of that SA6002 staticheck issues on
Github first results was Prometheus itself, with quite a lot of ignores
of it.
This changes the usages of `sync.Pool` to `zeropool.Pool[T]` where a
pointer is not available.
Also added a benchmark for HeadAppender Append/Commit when series
already exist, which is one of the most usual cases IMO, as I didn't find
any.
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
* Improve BenchmarkHeadAppender with more cases
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
* A little copying is better than a little dependency
https://www.youtube.com/watch?v=PAAkCSZUG1c&t=9m28s
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
* Fix imports order
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
* Add license header
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
* Copyright should be on one of the first 3 lines
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
* Use require.Equal for testing
I don't depend on testify in my lib, but here we have it available.
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
* Avoid flaky test
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
* Also use zeropool for pointsPool in engine.go
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
---------
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
We need to make sure that `tsdb_errors.NewMulti` handles the errors.Is()
calls properly, like it's done in grafana/dskit.
Also we need to check that `errors.Is(err, context.Canceled)`, not that
`err == context.Canceled`.
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
Test that blocks are not marked as "compaction failed" during shutdown.
This shouldn't happen but this test currently fails.
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
We need to make sure that `tsdb_errors.NewMulti` handles the errors.Is()
calls properly, like it's done in grafana/dskit.
Also we need to check that `errors.Is(err, context.Canceled)`, not that
`err == context.Canceled`.
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
Test that blocks are not marked as "compaction failed" during shutdown.
This shouldn't happen but this test currently fails.
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
It took a `Labels` where the memory could be re-used, but in practice
this hardly ever benefitted. Especially after converting `relabel.Process`
to `relabel.ProcessBuilder`.
Comparing the parameter to `nil` was a bug; `EmptyLabels` is not `nil`
so the slice was reallocated multiple times by `append`.
Lastly `Builder.Labels()` now estimates that the final size will depend
on labels added and deleted.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
We need to be able to identify the errors that a multierror wraps.
Especially in case of `context.Canceled`. This is the same
implementation of that method as we do in github.com/grafana/dskit/multierror
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
* Adds an affirmative log message for successful WAL repair
Signed-off-by: Vernon Miller <vernon.miller@grafana.com>
Signed-off-by: Vernon Miller <96601789+aldernero@users.noreply.github.com>
Co-authored-by: Ganesh Vernekar <ganeshvern@gmail.com>
Without this fix, if snapshots were enabled, and wbl goes missing
between restarts, then TSDB does not recognize that there are ooo
mmap chunks on disk and we cannot query them until those chunks
are compacted into blocks.
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
If the snapshot was enabled with some ooo mmap chunks on disk,
and wbl was removed between restarts, then we should still be able
to query the ooo mmap chunks after a restart. This test shows that
we are not able to query those ooo mmap chunks after a restart
under this situation.
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
M-map chunks replayed on startup are discarded if there
was no WAL and no snapshot loaded, because there is no
series created in the Head that it can map to. So only
load m-map chunks from disk if there is either a snapshot
loaded or there is WAL on disk.
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
Adds `WALReplayConcurrency` as an option on tsdb `Options` and `HeadOptions`.
If it is not set or set <=0, then `GOMAXPROCS` is used, which matches the previous behaviour.
Signed-off-by: Yuri Nikolic <durica.nikolic@grafana.com>
These benchmarks are all testing things related to what Prometheus does,
so perhaps have some historical interest, but we should not retain them
in the main repo.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
`safeChunk` is only obtained from the `headChunkReader.Chunk` call where
the chunk is already fetched and stored with the `safeChunk`. So, when
getting the iterator for the `safeChunk`, we don't need to get the chunk again.
Also removed a couple of unnecessary fields from `safeChunk` as a part of this.
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
* Export single ith test histogram generation functions
Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>
* Do not set counter reset hint for non-gauge histograms individually
Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>
* Apply suggestions from code review
Co-authored-by: Ganesh Vernekar <ganeshvern@gmail.com>
Signed-off-by: George Krajcsovits <krajorama@users.noreply.github.com>
---------
Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>
Signed-off-by: George Krajcsovits <krajorama@users.noreply.github.com>
Co-authored-by: Ganesh Vernekar <ganeshvern@gmail.com>
* tsdb: make sharding function a parameter
Instead of relying on `labels.Hash()`, which may change, have the
caller pass in a shard function if required.
For most purposes `tsdb.Options.ShardFunc` is used, but the compactor
may be created independently so `NewLeveledCompactorWithChunkSize` also
takes a shard function parameter.
Regular Prometheus, which does not use block sharding, will have this
parameter as nil.
Rename WithCache functions as WithOptions
Where they now have 2 or more extra parameters.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
This is a bit more conservative than we could be. As long as a chunk
isn't the first in a block, we can be pretty sure that the previous
chunk won't disappear. However, the incremental gain of returning
NotCounterReset in these cases is probably very small and might not be
worth the code complications.
Wwith this, we now also pay attention to an explicitly set counter
reset during ingestion. While the case doesn't show up in practice
yet, there could be scenarios where the metric source knows there was
a counter reset even if it might not be visible from the values in the
histogram. It is also useful for testing.
Signed-off-by: beorn7 <beorn@grafana.com>
- Adjust doc comments to go1.19 style.
- Break down some overly long lines.
- Minor doc comment tweaks and fixes.
- Some renaming.
Some rationales for the last point:
I have renamed “interjections” into “inserts”, mostly because it is
shorter, and the word shows up a lot by now (and the concept is
cryptic enough to not obfuscate it even more with abbreviations).
I have also tried to find more descriptive naming for the “compare
spans” functions.
Signed-off-by: beorn7 <beorn@grafana.com>
This is an optimization on the existing append in OOOChunk.
What we've been doing so far is find the place inside the out-of-order
slice where the new sample should go in and then place it there and move
any samples to the right if necessary. This is OK but requires a binary
search every time the slice is bigger than 0.
The optimization is opinionated and suggests that although out-of-order
samples can be out-of-order amongst themselves they'll probably be in
order thus we can probably optimistically append at the end and if not
do the binary search.
OOOChunks are capped to 30 samples by default so this is a small
optimization but everything adds up, specially if you handle many active
timeseries with out-of-order samples.
Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>
Signed-off-by: Jesus Vazquez <jesusvazquez@users.noreply.github.com>
Co-authored-by: Ganesh Vernekar <ganeshvern@gmail.com>
* adapt code.go and write_handler.go to support float histograms
* adapt watcher.go to support float histograms
* wip adapt queue_manager.go to support float histograms
* address comments for metrics in queue_manager.go
* set test cases for queue manager
* use same counts for histograms and float histograms
* refactor createHistograms tests
* fix float histograms ref in watcher_test.go
* address PR comments
Signed-off-by: Marc Tuduri <marctc@protonmail.com>
Instead of relying on `labels.Hash()`, which may change, have the
caller pass in a shard function if required.
For most purposes `tsdb.Options.ShardFunc` is used, but the compactor
may be created independently so `NewLeveledCompactorWithChunkSize` also
takes a shard function parameter.
Regular Prometheus, which does not use block sharding, will have this
parameter as nil.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
This is to check if a gauge histogram can be appended to the given chunk.
If not, it tells what changes to make to the chunk and the histogram
if possible.
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
In the head and in v1 postings on disk, it makes no difference whether
postings are sorted. Only for v2 does the code step through in order.
So, move the sorting to where it is required, and thus skip it entirely
in the head.
Label values in on-disk blocks are already sorted, but `slices.Sort` is
very fast on already-sorted data so we don't bother checking.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
This allocates memory for all the returned values, which skews the
result. We aren't trying to benchmark `ExpandPostings`, so just step
through all the values without storing them to consume them.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Previously all the postings constructed were consumed on the first
iteration, so subsequent iterations did no work.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
When out-of-order is enabled, queries go through both Head and OOOHead,
and they both execute the same PostingsForMatchers call, as memSeries
are shared for both.
In some cases these calls can be heavy, and also frequent. We can
deduplicate those calls by using the PostingsForMatchers cache that we
already use for query sharding.
The usage of this cache can skip a newly appended series in the results
for the duration of the ttl.
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
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>
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>
Implement decoding via labels.ScratchBuilder, which we retain and re-use
to reduce memory allocations.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
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>
