1 files changed, 64 insertions, 0 deletions
diff --git a/jstests/core/coveredIndex1.js b/jstests/core/coveredIndex1.js
new file mode 100644
index 00000000000..ce11f89ceed
--- /dev/null
+++ b/jstests/core/coveredIndex1.js
@@ -0,0 +1,64 @@
+
+t = db["jstests_coveredIndex1"];
+t.drop();
+
+t.save({fn: "john", ln: "doe"})
+t.save({fn: "jack", ln: "doe"})
+t.save({fn: "john", ln: "smith"})
+t.save({fn: "jack", ln: "black"})
+t.save({fn: "bob", ln: "murray"})
+t.save({fn: "aaa", ln: "bbb", obj: {a: 1, b: "blah"}})
+assert.eq( t.findOne({ln: "doe"}).fn, "john", "Cannot find right record" );
+assert.eq( t.count(), 6, "Not right length" );
+
+// use simple index
+t.ensureIndex({ln: 1});
+assert.eq( t.find({ln: "doe"}).explain().indexOnly, false, "Find using covered index but all fields are returned");
+assert.eq( t.find({ln: "doe"}, {ln: 1}).explain().indexOnly, false, "Find using covered index but _id is returned");
+assert.eq( t.find({ln: "doe"}, {ln: 1, _id: 0}).explain().indexOnly, true, "Find is not using covered index");
+
+// this time, without a query spec
+// SERVER-2109
+//assert.eq( t.find({}, {ln: 1, _id: 0}).explain().indexOnly, true, "Find is not using covered index");
+assert.eq( t.find({}, {ln: 1, _id: 0}).hint({ln: 1}).explain().indexOnly, true, "Find is not using covered index");
+
+// use compound index
+t.dropIndex({ln: 1})
+t.ensureIndex({ln: 1, fn: 1});
+// return 1 field
+assert.eq( t.find({ln: "doe"}, {ln: 1, _id: 0}).explain().indexOnly, true, "Find is not using covered index");
+// return both fields, multiple docs returned
+assert.eq( t.find({ln: "doe"}, {ln: 1, fn: 1, _id: 0}).explain().indexOnly, true, "Find is not using covered index");
+// match 1 record using both fields
+assert.eq( t.find({ln: "doe", fn: "john"}, {ln: 1, fn: 1, _id: 0}).explain().indexOnly, true, "Find is not using covered index");
+// change ordering
+assert.eq( t.find({fn: "john", ln: "doe"}, {fn: 1, ln: 1, _id: 0}).explain().indexOnly, true, "Find is not using covered index");
+// ask from 2nd index key
+assert.eq( t.find({fn: "john"}, {fn: 1, _id: 0}).explain().indexOnly, false, "Find is using covered index, but doesnt have 1st key");
+
+// repeat above but with _id field
+t.dropIndex({ln: 1, fn: 1})
+t.ensureIndex({_id: 1, ln: 1});
+// return 1 field
+assert.eq( t.find({_id: 123, ln: "doe"}, {_id: 1}).explain().indexOnly, true, "Find is not using covered index");
+// match 1 record using both fields
+assert.eq( t.find({_id: 123, ln: "doe"}, {ln: 1}).explain().indexOnly, true, "Find is not using covered index");
+// change ordering
+assert.eq( t.find({ln: "doe", _id: 123}, {ln: 1, _id: 1}).explain().indexOnly, true, "Find is not using covered index");
+// ask from 2nd index key
+assert.eq( t.find({ln: "doe"}, {ln: 1}).explain().indexOnly, false, "Find is using covered index, but doesnt have 1st key");
+
+// repeat above but with embedded obj
+t.dropIndex({_id: 1, ln: 1})
+t.ensureIndex({obj: 1});
+assert.eq( t.find({"obj.a": 1}, {obj: 1}).explain().indexOnly, false, "Shouldnt use index when introspecting object");
+assert.eq( t.find({obj: {a: 1, b: "blah"}}).explain().indexOnly, false, "Index doesnt have all fields to cover");
+assert.eq( t.find({obj: {a: 1, b: "blah"}}, {obj: 1, _id: 0}).explain().indexOnly, true, "Find is not using covered index");
+
+// repeat above but with index on sub obj field
+t.dropIndex({obj: 1});
+t.ensureIndex({"obj.a": 1, "obj.b": 1})
+assert.eq( t.find({"obj.a": 1}, {obj: 1}).explain().indexOnly, false, "Shouldnt use index when introspecting object");
+
+assert(t.validate().valid);
+