perf: inherit editorial on filtered variants (drops 75% Prom load per page)

src/app/benchmarks/[slug]/page.tsx

@@ -171,7 +171,31 @@ export default async function BenchmarkPage({
     ),
     getBenchmarks(),
   ]);
-  const variants: Record<string, Benchmark> = Object.fromEntries(variantList);
+  // Variants only contribute chart / leaderboard / extras to the displayed
+  // bench (those legitimately differ per (chain, region) filter). Editorial
+  // copy (findings, faq, seoIntro, abstract, methodology) is the SAME on
+  // every tab and only resolves chain placeholders against the aggregate's
+  // bestPerChain/worstPerChain stash (computed unfiltered only), so we
+  // override these fields onto every variant. Without this, switching to
+  // a chain tab surfaces raw `{{best_name:chain:X}}` strings.
+  const variants: Record<string, Benchmark> = Object.fromEntries(
+    variantList.map(([key, v]) => [
+      key,
+      v === aggregate
+        ? v
+        : {
+            ...v,
+            findings: aggregate.findings,
+            faq: aggregate.faq,
+            seoIntro: aggregate.seoIntro,
+            abstract: aggregate.abstract,
+            methodology: aggregate.methodology,
+            perChainExplainer: aggregate.perChainExplainer,
+            bestPerChain: aggregate.bestPerChain,
+            worstPerChain: aggregate.worstPerChain,
+          },
+    ]),
+  );
   const benchmark = variants[variantKey(chain, region)] ?? aggregate;
 
   const isDraft = benchmark.status === "draft";

src/lib/spec.ts

@@ -371,15 +371,15 @@ async function specToBenchmark(
     let bestPerChain: Record<string, ProviderResult> | undefined;
     let worstPerChain: Record<string, ProviderResult> | undefined;
     let providersPerChain: Record<string, string[]> | undefined;
-    // Compute per-chain leaders for BOTH unfiltered and filtered views.
-    // Filtered variants are pre-fetched by the page (one per chain × region
-    // combo) and end up in the RSC payload; their findings/seo_intro/faq
-    // reference `{{best_name:chain:X}}` for ALL chains, not just the
-    // currently selected one, so each variant needs the full stash to
-    // resolve those placeholders. Cached per (slug, filterSig) via
-    // loadBenchmarkFiltered's unstable_cache so the extra Prom roundtrips
-    // are paid once per variant, not per request.
-    if (spec.dimensions?.chain && spec.dimensions.chain.length > 0) {
+    // Per-chain leaders/trailers/presence are computed ONLY on the
+    // unfiltered view. Earlier this also ran for filtered variants to
+    // populate {{best_name:chain:X}} in the variant's editorial copy,
+    // but that quadrupled Prom load per page (3 extra queries × 9
+    // pre-fetched variants on benches like aggregator-head-lag). The
+    // filtered variants now inherit findings/faq/seoIntro from the
+    // aggregate via the page-level fetch in app/benchmarks/[slug]/page.tsx,
+    // so per-chain compute on filtered variants is no longer needed.
+    if (!isFiltered && spec.dimensions?.chain && spec.dimensions.chain.length > 0) {
       const chainValues = spec.dimensions.chain
         .map((c) => c.value)
         .filter((v) => v !== "all");