in posts 30 records:
posts.insert({
checkSum: checkSum, (md5)
topicId : topic, (integer)
topicName : name (long text, length ~ 100-200)
});
posts.find(null, null, function(results) {
sys.puts(results.length); //if results is "large" callback is not called, if results littleness we see output text 30
});