fix: window size for small time ranges

[srikanthccv]

Summary

There are two issues this change fixes

1. getMovingAvg returns an incorrect window average if the window size is larger than the length of the series. When does this happen? It happens when the eval window used in the alert is smaller, such as 5 minutes. This is not an issue for any eval window greater than 7 minutes.
2. The end of the season period should not include the eval window. These are 5 data points used to derive the predicted value

Let's assume daily seasonality

current period - time range choose from ui, or eval window time from an alert; let's say they are [start, end]

the current season should be in a time range till the start and shouldn't overlap with the current period.

the current logic is [start-1d, end], but it should be [start-1d, start]

Fixes #6963

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Important

Fix moving average calculation and seasonal period logic in anomaly detection, and simplify boolean check in alerts info retrieval.

• Behavior:
  • Fix getMovingAvg in seasonal.go to handle cases where window size exceeds series length by dynamically adjusting the window size.
  • Correct seasonal period calculation in prepareAnomalyQueryParams in params.go to exclude the evaluation window.
• Logging:
  • Change log level from Info to Debug for predicted series details in getPredictedSeries in seasonal.go.
• Misc:
  • Simplify boolean check in GetAlertsInfo in db.go by using !rule.PostableRule.Disabled.

^{This description was created by for 89b34ce. It will automatically update as commits are pushed.}

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👍 Looks good to me! Reviewed everything up to 89b34ce in 20 seconds

More details

• Looked at 103 lines of code in 3 files
• Skipped 0 files when reviewing.
• Skipped posting 2 drafted comments based on config settings.

1. pkg/query-service/rules/db.go:618

• Draft comment:
  The change from if rule.PostableRule.Disabled == false to if !rule.PostableRule.Disabled improves readability and is a good practice.
• Reason this comment was not posted:
  Confidence changes required: 10%
  The change in the conditional statement is a good practice for readability and maintainability.

2. pkg/query-service/rules/db.go:616

• Draft comment:
  Do not add non-ClickHouse related functions to the ClickHouseReader interface. Use the DAO in the telemetry instance to access such information instead. This is also applicable in other parts of the file where similar patterns are observed.
• Reason this comment was not posted:
  Comment was not on a valid diff hunk.

Workflow ID: wflow_vEFruML23CKVIgL5

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