SERVER-10565 added explain js test to check explain.n when query batch size is smaller than total number of documents requested

1 files changed, 19 insertions, 0 deletions

diff --git a/jstests/explain_batch_size.js b/jstests/explain_batch_size.js
new file mode 100644
index 00000000000..65bc1df40d7
--- /dev/null
+++ b/jstests/explain_batch_size.js
@@ -0,0 +1,19 @@
+// minimal test to check handling of batch size when explain info is requested
+// expected behavior is to return explain.n = total number of documents matching query
+// batch size is also tested in another smoke test jstest/explain1.js but that test
+// also covers the use of an indexed collection and includes a couple of test cases
+// using limit()
+
+t = db.explain_batch_size;
+t.drop();
+
+n = 3
+for (i=0; i<n; i++) {
+    t.save( { x : i } );
+}
+
+q = {};
+
+assert.eq( n , t.find( q ).count() , "A" );
+assert.eq( n , t.find( q ).itcount() , "B" );
+assert.eq( n , t.find( q ).batchSize(1).explain().n , "C" );