1 files changed, 48 insertions, 0 deletions
diff --git a/jstests/count8.js b/jstests/count8.js
new file mode 100644
index 00000000000..a8d4ce39103
--- /dev/null
+++ b/jstests/count8.js
@@ -0,0 +1,48 @@
+// Test count yielding, in both fast and normal count modes.
+
+t = db.jstests_count8;
+t.drop();
+
+function checkYield( dropCollection, fastCount, query ) {
+
+    obj = fastCount ? {a:true} : {a:1};
+    query = query || obj;
+    
+    passed = false;
+    for( nDocs = 20000; nDocs < 8000000; nDocs *= 2 ) {
+
+        t.drop();
+        t.ensureIndex( {a:1} );
+        for( i = 0; i < nDocs; ++i ) {
+            t.insert( obj );
+        }
+        db.getLastError();
+
+        if ( dropCollection ) {
+            p = startParallelShell( 'sleep( 30 ); db.jstests_count8.drop(); db.getLastError();' );
+        } else {
+            p = startParallelShell( 'sleep( 30 ); db.jstests_count8.update( {$atomic:true}, {$set:{a:-1}}, false, true ); db.getLastError();' );
+        }
+
+        printjson( query );
+        count = t.count( query );
+        // We test that count yields by requesting a concurrent operation modifying the collection
+        // and checking that the count result is modified.
+        print( 'count: ' + count + ', nDocs: ' + nDocs );
+        if ( count < nDocs ) {
+            passed = true;
+            p();
+            break;
+        }
+    
+        p();
+    }
+
+    assert( passed );
+}
+
+checkYield( true, false );
+checkYield( false, false );
+checkYield( true, true );
+checkYield( false, true );
+checkYield( true, false, {$or:[{a:1},{a:2}]} );