> use _tmp;
switched to db _tmp
Tue Feb 1 14:31:39 trying reconnect to 127.0.0.1
Tue Feb 1 14:31:39 reconnect 127.0.0.1 ok
> db.c.save( {} );
> db.c.count();
1
> db.c.count();
Tue Feb 1 14:31:50 DBClientCursor::init call() failed
Tue Feb 1 14:31:50 query failed : _tmp.$cmd { count: "c", query: {}, fields: {} } to: 127.0.0.1
Tue Feb 1 14:31:50 Error: error doing query: failed shell/collection.js:150
Tue Feb 1 14:31:50 trying reconnect to 127.0.0.1
Tue Feb 1 14:31:50 reconnect 127.0.0.1 ok
> db.c.count();
0
>

The mongod was restarted before the 2nd count() above.