SERVER-9365 make forced halfway split work with chunks with many docs

Additional test fixes.

1 files changed, 12 insertions, 5 deletions

diff --git a/src/mongo/s/d_split.cpp b/src/mongo/s/d_split.cpp
index 332a6300014..d28f3f5d90b 100644
--- a/src/mongo/s/d_split.cpp
+++ b/src/mongo/s/d_split.cpp
@@ -290,13 +290,14 @@ namespace mongo {
                 // 'force'-ing a split is equivalent to having maxChunkSize be the size of the current chunk, i.e., the
                 // logic below will split that chunk in half
                 long long maxChunkSize = 0;
-                bool force = false;
+                bool forceMedianSplit = false;
                 {
                     BSONElement maxSizeElem = jsobj[ "maxChunkSize" ];
                     BSONElement forceElem = jsobj[ "force" ];
                     
                     if ( forceElem.trueValue() ) {
-                        force = true;
+                        forceMedianSplit = true;
+                        // This chunk size is effectively ignored if force is true
                         maxChunkSize = dataSize;
                         
                     }
@@ -366,7 +367,8 @@ namespace mongo {
                     while ( cc->ok() ) {
                         currCount++;
                         
-                        if ( currCount > keyCount ) {
+                        if ( currCount > keyCount && !forceMedianSplit ) {
+
                             BSONObj currKey = bc->prettyKey( c->currKey() ).extractFields(keyPattern);
                             // Do not use this split key if it is the same used in the previous split point.
                             if ( currKey.woCompare( splitKeys.back() ) == 0 ) {
@@ -404,10 +406,15 @@ namespace mongo {
                         }
                     }
                     
-                    if ( splitKeys.size() > 1 || ! force )
+                    if ( ! forceMedianSplit )
                         break;
                     
-                    force = false;
+                    //
+                    // If we're forcing a split at the halfway point, then the first pass was just
+                    // to count the keys, and we still need a second pass.
+                    //
+
+                    forceMedianSplit = false;
                     keyCount = currCount / 2;
                     currCount = 0;
                     log() << "splitVector doing another cycle because of force, keyCount now: " << keyCount << endl;