Kumar Chandrachooda - KC Star V2 — Every Measure Gets Computed

Part 1 30 Jul 2025 4 min read

Eight Measures, One Table

KC Star V1 declared eight measures and computed four. V2 computes all eight - base measures and aggregates together in a single SalesFact table. Kicking off the series on the version that made the warehouse analytical, and started the trouble that V3 had to fix.

Part 2 31 Jul 2025 4 min read

Promoting SaleType from Row to Column

To compute per-SaleType aggregates, KC Star V2 lifted one dimension out of the row store and made it a real column. Here is the renumbering it forced, what it did to the version hash, and the honest tension of un-inverting one attribute in a schema built on inversion.

Part 3 01 Aug 2025 4 min read

GROUP BY in a Window Function's Clothes

KC Star V2's measure formulas read like window functions - SUM(...) OVER (PARTITION BY SaleType) - but the implementation is plain GROUP BY. Here is how CreateAggregatedFacts actually builds the aggregates, and why the formula strings deliberately lie.

Part 4 01 Aug 2025 4 min read

The Expiry Clause That Missed

KC Star V2 stores base facts and aggregates in one table and tells them apart by a NULL. When it expires old aggregates, that one distinction turns out to be a distinction short - per-SaleType aggregates never retire, duplicates pile up, and V3 gets its reason to exist.

KC Star V2 — Every Measure Gets Computed

Eight Measures, One Table

Promoting SaleType from Row to Column

GROUP BY in a Window Function's Clothes

The Expiry Clause That Missed

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