Update fetch.go

weed/mq/kafka/protocol/fetch.go

@@ -244,11 +244,13 @@ func (h *Handler) handleFetch(ctx context.Context, correlationID uint32, apiVers
 	// Phase 2: Wait for all results with adequate timeout for CI environments
 	// CRITICAL: We MUST return a result for every requested partition or Sarama will error
 	results := make([]*partitionFetchResult, len(pending))
-	// Use the client's requested MaxWaitTime plus a small buffer
-	// The 100ms buffer provides backpressure for downstream consumers (like Schema Registry's
-	// internal consumer) that may need time to catch up after rapid writes
-	deadline := time.After(time.Duration(maxWaitMs)*time.Millisecond - 50*time.Millisecond)
-	if maxWaitMs < 50 {
+	// Use 90% of client's MaxWaitTime to ensure we return BEFORE client timeout
+	// This gives us time to package and transmit the response before the client gives up
+	// For 500ms client timeout, we use 450ms internally, leaving 50ms buffer for:
+	// - Response serialization, network transmission, client processing
+	effectiveDeadlineMs := time.Duration(maxWaitMs) * 9 / 10
+	deadline := time.After(effectiveDeadlineMs * time.Millisecond)
+	if maxWaitMs < 10 {
 		deadline = time.After(time.Duration(maxWaitMs) * time.Millisecond)
 	}