wait for from writebacks in balancer CS-635

1 files changed, 8 insertions, 0 deletions

diff --git a/s/balancer_policy.cpp b/s/balancer_policy.cpp
index 2098a1f7faf..482fab06410 100644
--- a/s/balancer_policy.cpp
+++ b/s/balancer_policy.cpp
@@ -40,6 +40,8 @@ namespace mongo {
         pair<string,unsigned> max("",0);
         vector<string> drainingShards;
 
+        bool maxOpsQueued = false;
+
         for (ShardToChunksIter i = shardToChunksMap.begin(); i!=shardToChunksMap.end(); ++i ) {
 
             // Find whether this shard's capacity or availability are exhausted
@@ -67,6 +69,7 @@ namespace mongo {
             // Draining shards take a lower priority than overloaded shards.
             if ( size > max.second ) {
                 max = make_pair( shard , size );
+                maxOpsQueued = opsQueued;
             }
             if ( draining && (size > 0)) {
                 drainingShards.push_back( shard );
@@ -80,6 +83,11 @@ namespace mongo {
             return NULL;
         }
 
+        if ( maxOpsQueued ) {
+            log() << "biggest shard has unprocessed writebacks, waiting for completion of migrate" << endl;
+            return NULL;
+        }
+
         log(1) << "collection : " << ns << endl;
         log(1) << "donor      : " << max.second << " chunks on " << max.first << endl;
         log(1) << "receiver   : " << min.second << " chunks on " << min.first << endl;