mshahid6 opened a new pull request, #19225:
URL: https://github.com/apache/druid/pull/19225
### Description
Adds a new WeightedQueryLaningStrategy (strategy: "weighted") that scores
queries by how many configured thresholds they breach and assigns them to
graduated lanes with different capacity limits.
The existing HiLoQueryLaningStrategy uses a simple binary high/low split —
any single threshold breach sends a query to the low lane. This misclassifies
queries that are expensive on one dimension but cheap on others (e.g., many
segments but cheap per-segment). The weighted strategy provides more nuanced
lane assignment: a query breaching 1 threshold gets a different lane than one
breaching 4.
Same threshold types as ThresholdBasedQueryPrioritizationStrategy:
- periodThreshold — how far in the past the data is
- durationThreshold — how large the query interval is
- segmentCountThreshold — number of segments involved
- segmentRangeThreshold — total segment time range
Each breach adds 1 to the query's score (this can be changed to make scoring
different for each threshold). The query is assigned to the lane with the
highest minScore it meets. Score 0 = no lane (runs in default pool). Existing
caller-set lanes in query context are preserved.
**Example config**
{
"laning": {
"strategy": "weighted",
"periodThreshold": "P1M",
"durationThreshold": "P1D",
"segmentCountThreshold": 1000,
"segmentRangeThreshold": "P6M",
"lanes": {
"low": { "minScore": 1, "maxPercent": 30 },
"very-low": { "minScore": 3, "maxPercent": 10 }
}
}
}
A query breaching 2 thresholds (score=2) goes to low (30% capacity cap). A
query breaching all 4 (score=4) goes to very-low (10% cap). When a lane is
full, excess queries get HTTP 429.
#### Release note
New query laning strategy weighted that scores queries by how many
thresholds they breach (segment count, interval duration, data age, segment
range) and assigns them to configurable graduated lanes with different capacity
limits, providing more nuanced lane assignment than the existing binary hilo
strategy.
<hr>
##### Key changed/added classes in this PR
- WeightedQueryLaningStrategy
- QueryLaningStrategy
- WeightedQueryLaningStrategyTest
- QuerySchedulerTest
[can add to docs once reviewed]
This PR has:
- [ ] been self-reviewed.
- [ ] using the [concurrency
checklist](https://github.com/apache/druid/blob/master/dev/code-review/concurrency.md)
(Remove this item if the PR doesn't have any relation to concurrency.)
- [ ] added documentation for new or modified features or behaviors.
- [ ] a release note entry in the PR description.
- [ ] added Javadocs for most classes and all non-trivial methods. Linked
related entities via Javadoc links.
- [ ] added or updated version, license, or notice information in
[licenses.yaml](https://github.com/apache/druid/blob/master/dev/license.md)
- [ ] added comments explaining the "why" and the intent of the code
wherever would not be obvious for an unfamiliar reader.
- [ ] added unit tests or modified existing tests to cover new code paths,
ensuring the threshold for [code
coverage](https://github.com/apache/druid/blob/master/dev/code-review/code-coverage.md)
is met.
- [ ] added integration tests.
- [ ] been tested in a test Druid cluster.
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