One CI fix

Author: Thorium

tests/SqlProvider.Tests/more/PerformancePatternTests.fs

@@ -308,23 +308,32 @@ let ``index-friendly queries should perform well``() =
 let ``query performance should be consistent across multiple runs``() =
     let runs = 3
     let times = ResizeArray<int64>()
-    
+
+    let runQuery () =
+        query {
+            for customer in dc.Main.Customers do
+            take 10
+            select customer.CustomerId
+        } |> Seq.toArray
+
+    // Warm-up run: the first query pays JIT and initial-connection cost
+    // (e.g. 3 ms vs 1 ms on warm runs), which is not representative of steady-state variance.
+    runQuery() |> ignore
+
     for i in 1..runs do
-        let (_, time) = measureQueryPerformance $"Run{i}" (fun () ->
-            query {
-                for customer in dc.Main.Customers do
-                take 10
-                select customer.CustomerId
-            } |> Seq.toArray)
-        
+        let (_, time) = measureQueryPerformance $"Run{i}" runQuery
         times.Add(time)
-    
+
     let avgTime = times |> Seq.averageBy float
     let maxTime = times |> Seq.max
     let minTime = times |> Seq.min
-    
-    // Performance should be reasonably consistent
-    Assert.IsTrue(maxTime - minTime < int64(avgTime) * 2L) // Max variance of 2x average
+
+    // Performance should be reasonably consistent. These queries run in ~1-3 ms, so at the
+    // Stopwatch's millisecond resolution a single ms of scheduling jitter can exceed a purely
+    // relative bound. Allow an absolute slack floor for quantization, and round the average up
+    // (int64 truncation of e.g. 1.667 -> 1 would otherwise tighten the threshold).
+    let threshold = max 5L (int64 (ceil avgTime) * 2L) // Max variance: 2x average, min 5 ms slack
+    Assert.IsTrue(maxTime - minTime < threshold)
 
     printfn "Query times: Min=%d ms, Max=%d ms, Avg=%.1f ms" minTime maxTime avgTime