SERVER-4401 attempt to advance to next or clause if a cursor becomes invalid on yield recovery

1 files changed, 27 insertions, 0 deletions

diff --git a/jstests/distinct3.js b/jstests/distinct3.js
new file mode 100644
index 00000000000..f945ec9d7e8
--- /dev/null
+++ b/jstests/distinct3.js
@@ -0,0 +1,27 @@
+// Yield and delete test case for query optimizer cursor.
+
+t = db.jstests_distinct3;
+t.drop();
+
+t.ensureIndex({a:1});
+t.ensureIndex({b:1});
+
+for( i = 0; i < 50; ++i ) {
+    for( j = 0; j < 20; ++j ) {
+        t.save({a:i,c:i,d:j});
+    }
+}
+for( i = 0; i < 1000; ++i ) {
+    t.save({b:i,c:i+50});
+}
+db.getLastError();
+
+// The idea here is to try and remove the last match for the {a:1} index scan while distinct is yielding.
+p = startParallelShell( 'for( i = 0; i < 2500; ++i ) { db.jstests_distinct3.remove({a:49}); for( j = 0; j < 20; ++j ) { db.jstests_distinct3.save({a:49,c:49,d:j}) } }' );
+
+for( i = 0; i < 100; ++i ) {
+    count = t.distinct( 'c', {$or:[{a:{$gte:0},d:0},{b:{$gte:0}}]} ).length;
+    assert.gt( count, 1000 );
+}
+
+p();