When a KPI reads 163 billion instead of 819

Short summary

A metrics engine with dual query paths (SQL push-down vs. in-memory aggregation) drifted when a parameter was bound but never used in the WHERE clause, causing a KPI to sum across multiple series instead of filtering correctly—inflating one value from 819 to 163 billion. The fix: place shared predicates in a base WHERE inherited by all compile paths, and test both paths produce identical queries and results.

• •Two query paths drifted: parameter was bound but never referenced in WHERE clause, causing KPI to sum all series instead of filtering
• •KPI inflated from 819 to 163 billion by including hashed values from a second metric series
• •Solution: put shared predicates in base WHERE inherited by all paths, and test that both produce identical filters and answers

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