* tsdb: mmapCurrentOOOHeadChunk prepare for multiple ooo chunks
Currently float samples can only create a single ooo head chunk, but
native histograms can result in multiple due to counter resets, etc.
Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>
* tsdb: getOOOSeriesChunks prepare for multiple ooo chunks
Currently float samples can only create a single ooo head chunk, but
native histograms can result in multiple due to counter resets, etc.
Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>
---------
Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>
Check if headQuerier is nil before trying to use it.
* TestQueryOOOHeadDuringTruncate: unit test to check query during truncate
Regression test for #14822
* Simulate race between query and Compact()
Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>
`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>
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>
In `mmapCurrentOOOHeadChunk`, check if the number is at the maximum and
drop the data with an error log. This is not expected to happen as the
maximum is over 8 million; that's 8 years of 1 sample every second.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* Re-enable check in `createHeadWithOOOSamples` which wasn't really broken.
* Move code making `Block` into a `Queryable` into test file.
* Make `getSeriesChunks` return a slice (renamed `appendSeriesChunks`).
* Rename `oooMergedChunks` to `mergedChunks`.
* Improve comment on `ChunkOrIterableWithCopy`.
* Name return values from unpackHeadChunkRef.
Co-authored-by: Oleg Zaytsev <mail@olegzaytsev.com>
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Use headIndexReader instead.
OOOCompactionHeadIndexReader needs to be expanded slightly, because it previously delegated to OOOHeadIndexReader.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Add `HeadAndOOOQuerier` which iterates just once over series, then
where necessary merges chunks from in-order and out-of-order lists.
Add a ChunkQuerier for in-order and ooo together
Add copy-last-chunk behaviour to HeadAndOOOChunkReader
Out-of-order chunk IDs are distinguished from in-order by setting bit 23.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* TSDB: Document what needs locking in memSeries
* TSDB: Lock around access to series labels
So we can modify them to reset the symbol-table.
* TSDB: Make label locking conditional on build tag
---------
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Instead of carrying around extra fields in `Meta` structs which let us
approximate what was in the chunk at the time, take a copy of the chunk.
This simplifies lots of code, and lets us correct a couple of tests which
were embedding the wrong answer.
We can also remove boundedIterator, which was only used to constrain
the OOO head chunk.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
The only call we have to LabelValuesFor() has an index.Postings, and we
expand it to pass to this method, which will iterate over the values.
That's a waste of resources: we can iterate on the index.Postings
directly.
If there's any downstream implementation that has a slice of series,
they can always do an index.ListPostings from them: doing that is
cheaper than expanding an abstract index.Postings.
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
Add method `PostingsForLabelMatching` to `tsdb.IndexReader`, to obtain postings for labels with a certain name and values accepted by a provided callback, and use it from `tsdb.PostingsForMatchers`.
The intention is to optimize regexp matcher paths, especially not having to load all label values before matching on them.
Plus tests, and refactor some `tsdb/index.Reader` methods.
Benchmarking shows memory reduction up to ~100%, and speedup of up to ~50%.
Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>
Co-authored-by: Bartlomiej Plotka <bwplotka@gmail.com>
This PR is a reference implementation of the proposal described in #10420.
In addition to what described in #10420, in this PR I've introduced labels.StableHash(). The idea is to offer an hashing function which doesn't change over time, and that's used by query sharding in order to get a stable behaviour over time. The implementation of labels.StableHash() is the hashing function used by Prometheus before stringlabels, and what's used by Grafana Mimir for query sharding (because built before stringlabels was a thing).
Follow up work
As mentioned in #10420, if this PR is accepted I'm also open to upload another foundamental piece used by Grafana Mimir query sharding to accelerate the query execution: an optional, configurable and fast in-memory cache for the series hashes.
Signed-off-by: Marco Pracucci <marco@pracucci.com>
The ChunkReader interface's Chunk() has been changed to ChunkOrIterable().
This is a precursor to OOO native histogram support - with OOO native histograms, the chunks.Meta passed to Chunk() can result in multiple chunks being returned rather than just a single chunk (e.g. if oooMergedChunk has a counter reset in the middle).
To support this, ChunkOrIterable() requires either a single chunk or an iterable to be returned. If an iterable is returned, the caller has the responsibility of converting the samples from the iterable into possibly multiple chunks. The OOOHeadChunkReader now returns an iterable rather than a chunk to prepare for the native histograms case. Also as a beneficial side effect, oooMergedChunk and boundedChunk has been simplified as they only need to implement the Iterable interface now, not the full Chunk interface.
---------
Signed-off-by: Fiona Liao <fiona.y.liao@gmail.com>
Co-authored-by: George Krajcsovits <krajorama@users.noreply.github.com>
* Add failing test.
Signed-off-by: Charles Korn <charles.korn@grafana.com>
* Don't run OOO head garbage collection while reads are running.
Signed-off-by: Charles Korn <charles.korn@grafana.com>
* Add further test cases for different order of operations.
Signed-off-by: Charles Korn <charles.korn@grafana.com>
* Ensure all queriers are closed if `DB.blockChunkQuerierForRange()` fails.
Signed-off-by: Charles Korn <charles.korn@grafana.com>
* Ensure all queriers are closed if `DB.Querier()` fails.
Signed-off-by: Charles Korn <charles.korn@grafana.com>
* Invert error handling in `DB.Querier()` and `DB.blockChunkQuerierForRange()` to make it clearer
Signed-off-by: Charles Korn <charles.korn@grafana.com>
* Ensure that queries that touch OOO data can't block OOO head garbage collection forever.
Signed-off-by: Charles Korn <charles.korn@grafana.com>
* Address PR feedback: fix parameter name in comment
Co-authored-by: Jesus Vazquez <jesusvazquez@users.noreply.github.com>
Signed-off-by: Charles Korn <charleskorn@users.noreply.github.com>
* Address PR feedback: use `lastGarbageCollectedMmapRef`
Signed-off-by: Charles Korn <charles.korn@grafana.com>
* Address PR feedback: ensure pending reads are cleaned up if creating an OOO querier fails
Signed-off-by: Charles Korn <charles.korn@grafana.com>
---------
Signed-off-by: Charles Korn <charles.korn@grafana.com>
Signed-off-by: Charles Korn <charleskorn@users.noreply.github.com>
Co-authored-by: Jesus Vazquez <jesusvazquez@users.noreply.github.com>
* Make head block ULIDs descriptive
As far as I understand, these ULIDs aren't persisted anywhere, so it
should be safe to change them.
When debugging an issue, seeing an ULID like
`2ZBXFNYVVFDXFPGSB1CHFNYQTZ` or `33DXR7JA39CHDKMQ9C40H6YVVF` isn't very
helpful, so I propose to make them readable in their ULID string
version.
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
* Set a different ULID for RangeHead
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
---------
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
On a 32 bit architecture the size of int is 32 bits. Thus converting from
int64, uint64 can overflow it and flip the sign.
Try for yourself in playground:
package main
import "fmt"
func main() {
x := int64(0x1F0000001)
y := int64(1)
z := int32(x - y) // numerically this is 0x1F0000000
fmt.Printf("%v\n", z)
}
Prints -268435456 as if x was smaller.
Followup to #12650
Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>
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>
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>
