Series limit for TSDB blocks based ingester

[codesome]

What this PR does:

Adds series limit for TSDB blocks based ingester. Requires #2674

TODO

• Unit tests
• Handle these error where app.Add and app.AddFast is called - consider them to be soft errors
• What to do when there is no metric name?
• Update CHANGELOG.md

[pracucci]

Thanks @codesome for working on this! A part from the feedback left on #2674 I would be glad to see these changes covered by tests. Could you check out any existing test on limits (we should have something for chunks storage) and replicate them for the blocks storage too, please? Copying these tests (instead of trying to reuse them) is fine to me.

[codesome]

This PR is now ready for review. I was able to re-use the existing tests to add case for the ingester v2. I need help in deciding the desired action for metric name limit when there is no metric name in a series.

[pstibrany]

Great job! Thank you Ganesh!

[pracucci]

Good job! I left few nits, but overall looks good. I'm now going to review tests and do some manual tests.

[pracucci]

Thanks Ganesh to address my comments! I've also done some manual tests locally and worked fine. I tested both per-user and per-metric limit and made sure that counters get correctly decremented when head is compacted.

Would mind doing a simple function renaming for clarity, please? I would rename:

• seriesAddedFor() > increaseSeriesForMetric()
• removeMetricName() > decreaseSeriesForMetric()

Also, if I remember correctly the changes in TSDB, callback doesn't guarantee atomicity. If this is correct, we should improve a bit removeMetricName() and handle the case shard.m[metricName] does not exist?

[pracucci]

Also, if I remember correctly the changes in TSDB, callback doesn't guarantee atomicity. If this is correct, we should improve a bit removeMetricName() and handle the case shard.m[metricName] does not exist?

Discussed offline. Not an issue.