limit number of concurrent splitVectors SERVER-4296

2 files changed, 11 insertions, 1 deletions

diff --git a/s/chunk.cpp b/s/chunk.cpp
index 33b401a03f2..066265e1104 100644
--- a/s/chunk.cpp
+++ b/s/chunk.cpp
@@ -342,6 +342,12 @@ namespace mongo {
 
             if ( _dataWritten < splitThreshold / 5 )
                 return false;
+            
+            if ( ! getManager()->_splitTickets.tryAcquire() ) {
+                LOG(1) << "won't auto split becaue not enough tickets: " << getManager()->getns() << endl;
+                return false;
+            }
+            TicketHolderReleaser releaser( &getManager()->_splitTickets );
 
             // this is a bit ugly
             // we need it so that mongos blocks for the writes to actually be committed
@@ -504,7 +510,9 @@ namespace mongo {
         // The shard versioning mechanism hinges on keeping track of the number of times we reloaded ChunkManager's.
         // Increasing this number here will prompt checkShardVersion() to refresh the connection-level versions to
         // the most up to date value.
-        _sequenceNumber(++NextSequenceNumber)
+        _sequenceNumber(++NextSequenceNumber),
+
+        _splitTickets( 5 )
 
     {
         int tries = 3;
diff --git a/s/chunk.h b/s/chunk.h
index 8126af3a06e..3e981e90103 100644
--- a/s/chunk.h
+++ b/s/chunk.h
@@ -353,6 +353,8 @@ namespace mongo {
 
         const unsigned long long _sequenceNumber;
 
+        mutable TicketHolder _splitTickets; // number of concurrent splitVector we can do from a splitIfShould per collection
+        
         friend class Chunk;
         friend class ChunkRangeManager; // only needed for CRM::assertValid()
         static AtomicUInt NextSequenceNumber;