[HDX-5077] Move multi-series metric merge computation to ClickHouse

.changeset/metrics-ch-side-merge.md

@@ -0,0 +1,6 @@
+---
+'@hyperdx/common-utils': patch
+'@hyperdx/app': patch
+---
+
+Multi-series metric charts now run as a single composed ClickHouse query instead of one query per series joined client-side. The per-series queries are combined via UNION ALL and pivoted back into one row per (group, time bucket) in SQL, including ratio charts (`seriesReturnType: 'ratio'`) and both `ratioMode` variants, which previously divided the two result sets in the browser/node. Result shape, column naming (including same-alias `__{index}` disambiguation), gap semantics, and ratio semantics are unchanged; charts with many series render with fewer round trips, and "View SQL" for multi-series metric charts now shows the full query instead of only the first series.

packages/app/src/components/DBEditTimeChartForm/ChartEditorControls.tsx

@@ -344,12 +344,12 @@ export function ChartEditorControls({
               )}
               {/* Grouped ratios divide per-group by default; this opts into
                   share-of-total (each group's contribution to the blended
-                  rate). Only metric sources fan out to per-series queries
-                  merged client-side (see mergeResultSets/ratioMode) — other
-                  sources compute the ratio within-group in the DB, where
-                  ratioMode has no effect — so restrict to metric sources. No
-                  effect on ungrouped ratios either, so also gate on a Group
-                  By. */}
+                  rate). Only metric sources render the ratio over composed
+                  per-series branches where ratioMode applies (see
+                  renderMultiSeriesMetricChartConfig) — other sources compute
+                  the ratio within-group via divide(), where ratioMode has no
+                  effect — so restrict to metric sources. No effect on
+                  ungrouped ratios either, so also gate on a Group By. */}
               {fields.length === 2 &&
                 seriesReturnType === 'ratio' &&
                 tableSource?.kind === SourceKind.Metric &&

packages/cli/AGENTS.md

@@ -147,8 +147,8 @@ dashboard**:
    (`convertToTimeChartConfig` / `convertToNumberChartConfig` /
    `convertToTableChartConfig` / `convertToCategoricalChartConfig`).
 2. `shared/tileQuery.ts` executes it via `clickhouseClient.queryChartConfig()`
-   from common-utils — internally
-   `setChartSelectsAlias → splitChartConfigs → renderChartConfig`, identical to
+   from common-utils — internally `setChartSelectsAlias → renderChartConfig`
+   (one composed statement, even for multi-series metric charts), identical to
    the web's `useQueriedChartConfig` core (minus chunking / MV optimization /
    PromQL).
 3. `shared/chartData.ts` shapes the response (ports of

packages/cli/src/shared/tileQuery.ts

@@ -96,8 +96,8 @@ export async function fetchTileData({
   });
 
   // Same call the web frontend's useQueriedChartConfig makes —
-  // internally: setChartSelectsAlias → splitChartConfigs →
-  // renderChartConfig → query → join metric result sets.
+  // internally: setChartSelectsAlias → renderChartConfig → query (one
+  // composed statement, even for multi-series metric charts).
   const data = await clickhouseClient.queryChartConfig({
     config: queriedConfig,
     metadata,