1 00:00:07,520 --> 00:00:11,760 After watching this video, you will be able to explain working in small batches and 2 00:00:11,760 --> 00:00:14,640 recognize how single piece flow yields faster feedback 3 00:00:15,840 --> 00:00:19,280 Working in small batches is a concept from Lean Manufacturing. 4 00:00:20,000 --> 00:00:24,800 It is important in situations where fast feedback is required because it enables 5 00:00:24,800 --> 00:00:30,320 you to learn quickly from your decisions. You may be testing a hypothesis and you 6 00:00:30,320 --> 00:00:33,120 don't want to get too far before you know if it's going to work. 7 00:00:34,080 --> 00:00:40,000 Working in small batches allows you to experiment more, in order to quickly gain insights. 8 00:00:40,000 --> 00:00:43,760 In contrast, working in large batches that take months to complete 9 00:00:43,760 --> 00:00:50,480 means that you don't get feedback for months. Working in small batches also minimizes waste. 10 00:00:50,480 --> 00:00:55,360 Because you gain feedback faster and you don't waste time developing things your customer doesn't like. 11 00:00:56,000 --> 00:00:59,440 Using large batches, you may spend months developing something that 12 00:00:59,440 --> 00:01:03,600 isn't what the customer wanted. In keeping with DevOps practices of 13 00:01:03,600 --> 00:01:09,840 cross-functional teams and lightweight approaches, the best way to rapidly progress from development 14 00:01:09,840 --> 00:01:15,520 through test and operations into production in a matter of minutes is working in small batches. 15 00:01:16,480 --> 00:01:21,440 Let's take a look at an example of working in large batches versus small batches. 16 00:01:21,440 --> 00:01:23,840 Let's say I need to mail out one thousand brochures. 17 00:01:24,480 --> 00:01:28,960 The steps are I fold the brochures, insert the brochures into envelopes, 18 00:01:28,960 --> 00:01:32,480 seal the envelopes, and then stamp the envelopes with postage. 19 00:01:32,480 --> 00:01:37,360 We will use this brochure example to compare large batch and small batch execution. 20 00:01:38,960 --> 00:01:43,760 Let's say that I'm going to process the first thousand brochures in batches of 50. 21 00:01:43,760 --> 00:01:47,040 These are large batches, with 50 brochures in each batch. 22 00:01:47,040 --> 00:01:50,560 Assume that each step takes about six seconds to complete. 23 00:01:50,560 --> 00:01:55,440 So, I can do about 10 steps per minute. I start with the first step, which is folding. 24 00:01:55,440 --> 00:02:00,080 And at 10 per minute, it takes me about five minutes to fold 50 of them. 25 00:02:00,080 --> 00:02:03,680 Then I move on to the next step. The next step is inserting them all. 26 00:02:03,680 --> 00:02:08,080 I can do about 10 of them per minute, so it takes me five more minutes, plus the five 27 00:02:08,080 --> 00:02:14,320 minutes from before. Now I'm 10 minutes into it. Once I have them all folded and I insert it, I move 28 00:02:14,320 --> 00:02:18,400 on to the next step, which is sealing them all. If I’m sealing 10 per minute, I can do another 29 00:02:18,400 --> 00:02:21,600 50 in another five minutes. So, I'm up to 15 minutes 30 00:02:21,600 --> 00:02:27,120 at this point in wall clock time. Finally, I get to step four, stamping, and it took 31 00:02:27,120 --> 00:02:33,200 me 16 minutes to get my first finished product. This is the first time I have things that I can 32 00:02:33,200 --> 00:02:37,680 actually inspect to check the quality. What if the envelopes had no glue? 33 00:02:38,320 --> 00:02:41,840 It would be 11 minutes before I figured out that something went wrong. 34 00:02:42,400 --> 00:02:46,240 What if there's a typo on the brochure? I have to go all the way back to the beginning. 35 00:02:46,240 --> 00:02:50,240 So, this is very wasteful working in these large batches. 36 00:02:50,240 --> 00:02:54,560 Now let's look at the same example with small batches using single piece flow. 37 00:02:55,280 --> 00:02:58,800 Again, assume each step takes about six seconds to complete. 38 00:02:58,800 --> 00:03:02,720 With single piece flow, I fold one, and put it into the envelope and seal 39 00:03:02,720 --> 00:03:07,520 it and put a stamp on it and the first finished product is about 24 seconds. 40 00:03:07,520 --> 00:03:11,920 Now I can inspect it, see if it works, see if it's what I thought it was, 41 00:03:12,480 --> 00:03:15,680 and then let the rest of the flow continue if it was acceptable. 42 00:03:16,240 --> 00:03:21,040 I received fast feedback in only 24 seconds instead of 11 minutes with the large batch. 43 00:03:21,760 --> 00:03:25,120 What if the envelopes had no glue? I would find out in about 18 seconds. 44 00:03:25,120 --> 00:03:28,080 And if there was a typo in the brochure, after 24 seconds. 45 00:03:28,080 --> 00:03:31,680 It’s very important that we don't work in large batches. 46 00:03:31,680 --> 00:03:35,280 We need fast feedback, so that we can quickly pivot if we need 47 00:03:35,280 --> 00:03:39,120 to do something different. Working in small batches 48 00:03:39,120 --> 00:03:43,920 helps you implement other DevOps practices like Continuous Integration and Continuous Delivery. 49 00:03:44,560 --> 00:03:46,560 So how do you know if your batches are small enough? 50 00:03:47,280 --> 00:03:50,320 I would start with the size of your stories in your backlog. 51 00:03:51,040 --> 00:03:56,400 Are your application features decomposed in such a way as to support frequent releases? 52 00:03:56,960 --> 00:04:00,160 You have to ask yourself, how often are releases possible? 53 00:04:00,160 --> 00:04:02,800 Are there delays in the release because the features are too large? 54 00:04:03,520 --> 00:04:08,080 Can features be completed in a sprint? If you have features that take several sprints, 55 00:04:08,080 --> 00:04:12,240 then your batches are too large. Optimally a feature should be 56 00:04:12,240 --> 00:04:18,560 small enough to be completed in a week or less. The features you build are one step toward a goal. 57 00:04:18,560 --> 00:04:21,920 Many people feel that only a completed goal is worth shipping. 58 00:04:21,920 --> 00:04:25,280 Instead of thinking of useful subsets that can be delivered in increments 59 00:04:25,280 --> 00:04:28,077 to gain feedback towards the ultimate goal. 60 00:04:29,191 --> 00:04:31,120 In this video, you learned that 61 00:04:31,120 --> 00:04:34,480 working in small batches means delivering something useful quickly. 62 00:04:35,440 --> 00:04:39,315 And using single piece flow leads to faster feedback loops.