9,104 rows in, 5,000 out: the silent cap that made my dashboard lie

Short summary

A silent 5,000-row cap in a generic query endpoint truncated 9,104 rows of search-rank data, causing a dashboard to show 'no change' instead of missing data. The bug stayed hidden because absence and zero rendered identically, and the cap returned HTTP 200 with no warning. The fix: fold windowing logic into SQL using Postgres DISTINCT ON so response size is bounded by keyword count, not row count, and always surface truncation explicitly in the response body.

• •Silent row caps that return HTTP 200 cause dashboards to lie by showing missing data as zero or no-change
• •Fix: use Postgres DISTINCT ON to compute latest-per-key in SQL, bounding response by entity count not row count
• •Missing and zero are different values and must render differently; always include truncated:true in capped responses

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