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>
In storage/remote, try converting to RecoverableError using errors.As,
instead of through direct casting.
Signed-off-by: Arve Knudsen <arve.knudsen@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>
`QueueManager.externalLabels` becomes a slice rather than a `Labels` so
we can index into it when doing the merge operation.
Note we avoid calling `Labels.Len()` in `labelProtosToLabels()`.
It isn't necessary - `append()` will enlarge the buffer and we're
expecting to re-use it many times.
Also, we now validate protobuf input before converting to Labels.
This way we can detect errors first, and we don't place unnecessary
requirements on the Labels structure.
Re-do seriesFilter using labels.Builder (albeit N^2).
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
The wlog.WL type can now be used to create a Write Ahead Log or a Write
Behind Log.
Before the prefix for wbl metrics was
'prometheus_tsdb_out_of_order_wal_' and has been replaced with
'prometheus_tsdb_out_of_order_wbl_'.
Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>
Signed-off-by: Jesus Vazquez <jesusvazquez@users.noreply.github.com>
Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
* Rename walDir parameter to dir
Signed-off-by: Matej Gera <matejgera@gmail.com>
* Improve NewQueueManager comment
Signed-off-by: Matej Gera <matejgera@gmail.com>
If FlushAndShutdown is called with a full batchQueue, and then Batch is
called rather than the normal path of reading from a queue a deadlock
might be encountered. Rather than having FlushAndShutdown having
blocking code while holding a lock retry sending the batch every second.
Signed-off-by: Chris Marchbanks <csmarchbanks@gmail.com>
Do not block when trying to write a batch to the queue. This can cause
appends to lock forever if the only thing reading from the queue needs
the mutex to write. Instead, if batchQueue is full pop the sample that
was just added from the partial batch and return false. The code doing
the appending already handles retries with backoff.
Signed-off-by: Chris Marchbanks <csmarchbanks@gmail.com>
If a queue is stopped and one of its shards happens to hit the
batch_send_deadline at the same time a deadlock can occur where stop
holds the mutex and will not release it until the send is finished, but
the send needs the mutex to retrieve the most recent batch. This is
fixed by using a second mutex just for writing.
In addition, the test I wrote exposed a case where during shutdown a
batch could be sent twice due to concurrent calls to queue.Batch() and
queue.FlushAndShutdown(). Protect these with a mutex as well.
Signed-off-by: Chris Marchbanks <csmarchbanks@gmail.com>
Previously we would reject an increase from 2 to 2.5 as being
within 30%; by rounding up first we see this as an increase from 2 to 3.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Change the coefficient from 1% to 5%, so instead of targetting to clear
the backlog in 100s we target 20s.
Update unit test to reflect the new behaviour.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
We have an alert that fires when prometheus_remote_storage_highest_timestamp_in_seconds - prometheus_remote_storage_queue_highest_sent_timestamp_seconds
becomes too high. But we have an agent that fires this when the remote "rate-limits" the user.
This is because prometheus_remote_storage_queue_highest_sent_timestamp_seconds doesn't get updated
when the remote sends a 429.
I think we should update the metrics, and the change I made makes sense. Because if the requests fails
because of connectivity issues, etc. we will never exit the `sendWriteRequestWithBackoff` function. It only
exits the function when there is a non-recoverable error, like a bad status code, and in that case, I think
the metric needs to be updated.
Signed-off-by: Goutham Veeramachaneni <gouthamve@gmail.com>
Right now the values for enqueuedSamples and enqueuedExemplars is never
subtracted leading to inflated values for failedSamples/failedExemplars
when a hard shutdown of a shard occurs.
Signed-off-by: Chris Marchbanks <csmarchbanks@gmail.com>
Channels can cause bottlenecks and tons of context switches when reading
hundreds of thousands of samples per second from a single queue.
Instead, pre-batch the samples to amortize the cost of the concurrency
overhead.
Signed-off-by: Chris Marchbanks <csmarchbanks@gmail.com>
This creates a new `model` directory and moves all data-model related
packages over there:
exemplar labels relabel rulefmt textparse timestamp value
All the others are more or less utilities and have been moved to `util`:
gate logging modetimevfs pool runtime
Signed-off-by: beorn7 <beorn@grafana.com>
* TSDB: demistify seriesRefs and ChunkRefs
The TSDB package contains many types of series and chunk references,
all shrouded in uint types. Often the same uint value may
actually mean one of different types, in non-obvious ways.
This PR aims to clarify the code and help navigating to relevant docs,
usage, etc much quicker.
Concretely:
* Use appropriately named types and document their semantics and
relations.
* Make multiplexing and demuxing of types explicit
(on the boundaries between concrete implementations and generic
interfaces).
* Casting between different types should be free. None of the changes
should have any impact on how the code runs.
TODO: Implement BlockSeriesRef where appropriate (for a future PR)
Signed-off-by: Dieter Plaetinck <dieter@grafana.com>
* feedback
Signed-off-by: Dieter Plaetinck <dieter@grafana.com>
* agent: demistify seriesRefs and ChunkRefs
Signed-off-by: Dieter Plaetinck <dieter@grafana.com>
By holding a `proto.Buffer` per shard and passing it down to where
marshalling is done, we avoid creating a lot of garbage.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* Moved everything to nPending buffer
Signed-off-by: Levi Harrison <git@leviharrison.dev>
* Simplify exemplar capacity addition
Signed-off-by: Levi Harrison <git@leviharrison.dev>
* Added pre-allocation
Signed-off-by: Levi Harrison <git@leviharrison.dev>
* Don't allocate if not sending exemplars
Signed-off-by: Levi Harrison <git@leviharrison.dev>
* Refactor: pass segment-reading function as param
To allow a different implementation to be used when garbage-collecting.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* remote_write: reduce blocking from GC of series
Add a method `UpdateSeriesSegment()` which is used together with
`SeriesReset()` to garbage-collect old series. This allows us to
split the lock around queueManager series data and avoid blocking
`Append()` while reading series from the last checkpoint.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* Cosmetic: review feedback on comments
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* remote-write benchmark: include GC of series
Reduce the total number of samples per iteration from 5000*5000
(25 million) which is too big for my laptop, to 1*10000.
Extend `createTimeseries()` to add additional labels, so that the
queue manager is doing more realistic work.
Move the Append() call to a background goroutine - this works because
TestWriteClient uses a WaitGroup to signal completion.
Call `StoreSeries()` and `SeriesReset()` while adding samples, to
simulate the garbage-collection that wal.Watcher does.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* Change BenchmarkSampleDelivery to call UpdateSeriesSegment
This matches what Watcher.garbageCollectSeries() is doing now
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* Added MaxSamplesPerSend
Signed-off-by: Levi Harrison <git@leviharrison.dev>
* Added tests
Signed-off-by: Levi Harrison <git@leviharrison.dev>
* Fixed order of require
Signed-off-by: Levi Harrison <git@leviharrison.dev>
* Added docs
Signed-off-by: Levi Harrison <git@leviharrison.dev>
* writes -> writesReceived
Signed-off-by: Levi Harrison <git@leviharrison.dev>
* Improved send loop
Signed-off-by: Levi Harrison <git@leviharrison.dev>
* Write exemplars to the WAL and send them over remote write.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Update example for exemplars, print data in a more obvious format.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Add metrics for remote write of exemplars.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Fix incorrect slices passed to send in remote write.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* We need to unregister the new metrics.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address review comments
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Order of exemplar append vs write exemplar to WAL needs to change.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Several fixes to prevent sending uninitialized or incorrect samples with an exemplar. Fix dropping exemplar for missing series. Add tests for queue_manager sending exemplars
Signed-off-by: Martin Disibio <mdisibio@gmail.com>
* Store both samples and exemplars in the same timeseries buffer to remove the alloc when building final request, keep sub-slices in separate buffers for re-use
Signed-off-by: Martin Disibio <mdisibio@gmail.com>
* Condense sample/exemplar delivery tests to parameterized sub-tests
Signed-off-by: Martin Disibio <mdisibio@gmail.com>
* Rename test methods for clarity now that they also handle exemplars
Signed-off-by: Martin Disibio <mdisibio@gmail.com>
* Rename counter variable. Fix instances where metrics were not updated correctly
Signed-off-by: Martin Disibio <mdisibio@gmail.com>
* Add exemplars to LoadWAL benchmark
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* last exemplars timestamp metric needs to convert value to seconds with
ms precision
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Process exemplar records in a separate go routine when loading the WAL.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address review comments related to clarifying comments and variable
names. Also refactor sample/exemplar to enqueue prompb types.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Regenerate types proto with comments, update protoc version again.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Put remote write of exemplars behind a feature flag.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address some of Ganesh's review comments.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Move exemplar remote write feature flag to a config file field.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address Bartek's review comments.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Don't allocate exemplar buffers in queue_manager if we're not going to
send exemplars over remote write.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Add ValidateExemplar function, validate exemplars when appending to head
and log them all to WAL before adding them to exemplar storage.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address more reivew comments from Ganesh.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Add exemplar total label length check.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address a few last review comments
Signed-off-by: Callum Styan <callumstyan@gmail.com>
Co-authored-by: Martin Disibio <mdisibio@gmail.com>
* Consider status code 429 as recoverable errors to avoid resharding.
* Adds support for Retry-After in backoff logic in remote storage.
Signed-off-by: Harkishen-Singh <harkishensingh@hotmail.com>
Currently there is no way of tracking the value of the
`max_samples_per_send` configuration option, which is commonly tweaked
when integrating with a remote write backend.
Signed-off-by: Jorge Luis Betancourt Gonzalez <jorge-luis.betancourt@trivago.com>
