From 8ea94ebb580612a21efaee6a344c110f59c659ce Mon Sep 17 00:00:00 2001
From: Fabian Reinartz <fab.reinartz@gmail.com>
Date: Tue, 12 May 2015 12:03:30 +0200
Subject: [PATCH] Check context before each preloading.

---
 promql/analyzer.go | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/promql/analyzer.go b/promql/analyzer.go
index a4d2521f9..32bdc64ed 100644
--- a/promql/analyzer.go
+++ b/promql/analyzer.go
@@ -131,19 +131,21 @@ func (a *Analyzer) Prepare(ctx context.Context) (local.Preloader, error) {
 
 	// Preload all analyzed ranges.
 	for offset, pt := range a.offsetPreloadTimes {
-		if err = contextDone(ctx, env); err != nil {
-			return nil, err
-		}
-
 		start := a.Start.Add(-offset)
 		end := a.End.Add(-offset)
 		for fp, rangeDuration := range pt.ranges {
+			if err = contextDone(ctx, env); err != nil {
+				return nil, err
+			}
 			err = p.PreloadRange(fp, start.Add(-rangeDuration), end, *stalenessDelta)
 			if err != nil {
 				return nil, err
 			}
 		}
 		for fp := range pt.instants {
+			if err = contextDone(ctx, env); err != nil {
+				return nil, err
+			}
 			err = p.PreloadRange(fp, start, end, *stalenessDelta)
 			if err != nil {
 				return nil, err