Service-Level Objectives¶

These SLOs govern the pipeline that produces the Gold tables consumed by the weekday dashboard.

1. Objectives at a Glance¶

ID	Objective	What We Care About	Hard Target
T-1	Timeliness	Data for calendar day D1 is ready for the dashboard	Gold committed ≤ 09:00 Europe/London every business day
C-1	Completeness	All expected entities & mandatory attributes are present	• 100 % business-key coverage • 0 NULLs in non-nullable columns
Q-1	Quality	Only valid data reaches consumers	• 0 duplicate primary keys • 0 negative sales values

2 Timeliness (T-1)¶

The Gold tables must be ready by 09:00 Europe/London each business day.

Item	Spec
SLI	`ready_by_09` is `True` if the last Gold table for day D commits by 09:00 local; else `False`.
Target	≥ 99 % of UK business days (max 1 miss per 30 days).
Measurement	Daily evaluation of `ready_by_09`.

3 Completeness (C-1)¶

Gold outputs must contain all expected entities and no NULLs in required fields.

Aspect	SLI	Target	Importance
Business-key coverage	`distinct_keys_gold / distinct_keys_expected`	= 100 %	Ensures completeness of entities.
Mandatory attributes	`% rows where non-nullable columns are non-NULL`	= 100 %	Ensures data usability and reliability.

4 Quality (Q-1)¶

These SLOs prevent invalid data from reaching consumers. Any breach triggers a hard block and suspends the Timeliness SLO for that day.

Rule	SLI	Target	Enforcement
Duplicate PKs	`dupe_pk_count`	0 per run	Abort run and alert.
Negative sales values	`neg_sales_count`	0 per run	Abort run and alert.

The SLO tracker aggregates the metadata.data_quality_checks log each day. The resulting counts of error-level failures are stored in metadata.quality, allowing breaches of the Q-1 SLO to be monitored over time.