TRY IT · COMPUTED CONTRACT MODEL

Read savings create write obligations.

Play the read, then the update. Change selectivity and key changes. Candidate inspections and key maintenance remain separate units; the model does not invent a speedup.

DocumentsRegionsRead queriesUpdated documents

Index the typed region projection Update changes the region key

100generated candidate inspections across reads

24modeled key-entry remove/insert operations

120stored index entries

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With 120 documents, 12 regions and 10 queries, the model compares 100 indexed candidates with 1200 unindexed candidates. Twelve changed keys add 24 remove/insert actions. Uncheck key change: no modeled relocation occurs, which still does not prove zero real update cost.

Synthetic equal-sized region buckets and a declared maintenance model, not SQL Server plan execution. One changed indexed value counts as one removal plus one insertion. This excludes physical pages, logging, expression evaluation, key width, locking and optimizer choice. Read inspections and key-entry actions are not interchangeable time units.