The integral accumulator in the remote write sharding code is just a
second way of keeping track of the number of samples pending. Remove
integralAccumulator and use the samplesPending value we already
calculate to calculate the number of shards.
This has the added benefit of fixing a bug where the integralAccumulator
was not being initialized correctly due to not taking into account the
number of ticks being counted, causing the integralAccumulator initial
value to be off by an order of magnitude in some cases.
Signed-off-by: Chris Marchbanks <csmarchbanks@gmail.com>
* Track remote write queues via a map so we don't care about index.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Support a job name for remote write/read so we can differentiate between
them using the name.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Remote write/read has Name to not confuse the meaning of the field with
scrape job names.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Split queue/client label into remote_name and url labels.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Don't allow for duplicate remote write/read configs.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Ensure we restart remote write queues if the hash of their config has
not changed, but the remote name has changed.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Include name in remote read/write config hashes, simplify duplicates
check, update test accordingly.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
It is possible that desired shards is always a bit higher than the
number of shards (less than 30%) and by exporting desired shards as the
raw number it will be easy to tell if a Prometheus is in that situation.
Signed-off-by: Chris Marchbanks <csmarchbanks@gmail.com>
* Refactor calculateDesiredShards + don't reshard if we're having issues
sending samples.
* Track lastSendTimestamp via an int64 with atomic add/load, add a test
for reshard calculation.
* Simplify conditional for skipping resharding, add samplesIn/Out to shard
testcase struct.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
The WAL Watcher replays a checkpoint after it is created in order to
garbage collect series that no longer exist in the WAL. Currently the
garbage collection process is done serially with reading from the tip of
the WAL which can cause large delays in writing samples to remote
storage just after compaction occurs.
This also fixes a memory leak where dropped series are not cleaned up as
part of the SeriesReset process.
Signed-off-by: Chris Marchbanks <csmarchbanks@gmail.com>
The desired shards calculation now properly keeps track of the rate of
pending samples, and uses the previously unused integralAccumulator to
adjust for missing information in the desired shards calculation.
Also, configure more capacity for each shard. The default 10 capacity
causes shards to block on each other while
sending remote requests. Default to a 500 sample capacity and explain in
the documentation that having more capacity will help throughput.
Signed-off-by: Chris Marchbanks <csmarchbanks@gmail.com>
* Add benchmark for sample delivery
* Simplify StoreSeries to have only one loop
* Reduce allocations for pending samples in runShard
* Only allocate one send slice per segment
* Cache a buffer in each shard for snappy to use
* Remove queue manager seriesMtx
It is not possible for any of the places protected by the seriesMtx to
be called concurrently so it is safe to remove. By removing the mutex we
can simplify the Append code to one loop.
Signed-off-by: Chris Marchbanks <csmarchbanks@gmail.com>
* Don't panic if we try to release a string that is not in the interner.
* Move seriesMtx locking in QueueManager's StoreSeries function.
This stops us from calling release for strings that aren't interned if
there's a race between reading a checkpoint and storing new series
labels, which could happen during checkpointing or reloading config.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Unregister remote write queue manager specific metrics when stopping the
queue manager.
* Use DeleteLabelValues instead of Unregister to remove queue and watcher
related metrics when we stop them. Create those metrics in the structs
start functions rather than in their constructors because of the
ordering of creation, start, and stop in remote storage ApplyConfig.
* Add setMetrics function to WAL watcher so we can set
the watchers metrics in it's Start function, but not
have to call Start in some tests (causes data race).
Signed-off-by: Callum Styan <callumstyan@gmail.com>
a string when there are no longer any refs. Add tests for interning.
Co-authored-by: Tom Wilkie <tom.wilkie@gmail.com>
Signed-off-by: Callum Styan <callumstyan@gmail.com>
- Unmarshall external_labels config as labels.Labels, add tests.
- Convert some more uses of model.LabelSet to labels.Labels.
- Remove old relabel pkg (fixes#3647).
- Validate external label names.
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
* Consistently pre-lookup the metrics for a given queue in queue manager.
* Don't open the WAL (for writing) in the remote_write code.
* Add some more logging.
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
- Remove prometheus_remote_queue_last_send_timestamp_seconds metric. Its not particularly useful, we have highest_timestamp_seconds.
- Factor out maxGauage, a gauge that only increases.
- Change sharding calculations to use max samples in timestamp - max samples out timestamp (not rates).
- Also include the ratio of samples dropped to correctly predict number of pending samples.
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
- Add a dropped samples EWMA and use it in calculating desired shards.
- Update metric names and a log messages.
- Limit number of entries in the dedupe logging middleware to prevent potential OOM.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
- If we're replaying the WAL to get series records, skip that segment when we hit corruptions.
- If we're tailing the WAL for samples, fail the watcher.
- When the watcher fails, restart from the latest checkpoint - and only send new samples by updating startTime.
- Tidy up log lines and error handling, don't return so many errors on quiting.
- Expect EOF when processing checkpoints.
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
- Use the queue name in WAL watcher logging.
- Don't return from watch if the reader error was EOF.
- Fix sample timestamp check logic regarding what samples we send.
- Refactor so we don't need readToEnd/readSeriesRecords
- Fix wal_watcher tests since readToEnd no longer exists
Signed-off-by: Callum Styan <callumstyan@gmail.com>
- Remove datarace in the exported highest scrape timestamp.
- Backoff on enqueue should be per-sample - reset the result for each sample.
- Remove diffKeys, unused ctx and cancelfunc in WALWatcher, 'name' from writeTo interface, and pass it to constructor.
- Reorder functions in WALWatcher depth-first according to call graph.
- Fix vendor/modules.txt.
- Split out the various timer periods into consts at the top of the file.
- Move w.currentSegmentMetric.Set close to where we set the currentSegment.
- Combine r.Next() and isClosed(w.quit) into a single loop.
- Unnest some ifs in WALWatcher.watch, propagate erros in decodeRecord, add some new lines to make it easier to read.
- Reorganise checkpoint handling to reduce nesting and make it easier to follow.
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
This change switches the remote_write API to use the TSDB WAL. This should reduce memory usage and prevent sample loss when the remote end point is down.
We use the new LiveReader from TSDB to tail WAL segments. Logic for finding the tracking segment is included in this PR. The WAL is tailed once for each remote_write endpoint specified. Reading from the segment is based on a ticker rather than relying on fsnotify write events, which were found to be complicated and unreliable in early prototypes.
Enqueuing a sample for sending via remote_write can now block, to provide back pressure. Queues are still required to acheive parallelism and batching. We have updated the queue config based on new defaults for queue capacity and pending samples values - much smaller values are now possible. The remote_write resharding code has been updated to prevent deadlocks, and extra tests have been added for these cases.
As part of this change, we attempt to guarantee that samples are not lost; however this initial version doesn't guarantee this across Prometheus restarts or non-retryable errors from the remote end (eg 400s).
This changes also includes the following optimisations:
- only marshal the proto request once, not once per retry
- maintain a single copy of the labels for given series to reduce GC pressure
Other minor tweaks:
- only reshard if we've also successfully sent recently
- add pending samples, latest sent timestamp, WAL events processed metrics
Co-authored-by: Chris Marchbanks <csmarchbanks.com> (initial prototype)
Co-authored-by: Tom Wilkie <tom.wilkie@gmail.com> (sharding changes)
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* *: use latest release of staticcheck
It also fixes a couple of things in the code flagged by the additional
checks.
Signed-off-by: Simon Pasquier <spasquie@redhat.com>
* Use official release of staticcheck
Also run 'go list' before staticcheck to avoid failures when downloading packages.
Signed-off-by: Simon Pasquier <spasquie@redhat.com>
More than one remote_write destination can be configured, in which
case it's essential to know which one each log message refers to.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
