Abort query if not enough stake connected

Signed-off-by: Yacov Manevich <[email protected]>

snow/engine/snowman/engine.go

@@ -31,7 +31,10 @@ import (
 	"github.com/ava-labs/avalanchego/utils/units"
 )
 
-const nonVerifiedCacheSize = 64 * units.MiB
+const (
+	minConnectedStakeToQuery = 0.75
+	nonVerifiedCacheSize     = 64 * units.MiB
+)
 
 var _ common.Engine = (*Engine)(nil)
 
@@ -875,6 +878,17 @@ func (e *Engine) sendQuery(
 		zap.Stringer("validators", e.Validators),
 	)
 
+	stakeConnectedRatio := e.Config.ConnectedValidators.ConnectedPercent()
+
+	if stakeConnectedRatio < minConnectedStakeToQuery {
+		e.Ctx.Log.Warn("dropped query for block",
+			zap.String("reason", "insufficient stake connected"),
+			zap.Stringer("blkID", blkID),
+			zap.Float64("ratio", stakeConnectedRatio),
+		)
+		return
+	}
+
 	vdrIDs, err := e.Validators.Sample(e.Ctx.SubnetID, e.Params.K)
 	if err != nil {
 		e.Ctx.Log.Warn("dropped query for block",