1 00:00:00,350 --> 00:00:01,330 So let's talk about 2 00:00:01,330 --> 00:00:03,830 the other kind of queues available in SQS 3 00:00:03,830 --> 00:00:07,200 called the Amazon SQS FIFO Queues. 4 00:00:07,200 --> 00:00:09,800 FIFO means first in first out. 5 00:00:09,800 --> 00:00:12,100 What this means is that the messages will be ordered 6 00:00:12,100 --> 00:00:14,710 in the queue and the first message to arrive in the queue 7 00:00:14,710 --> 00:00:17,080 will be the first message to leave the queue. 8 00:00:17,080 --> 00:00:20,000 So this is more ordering guarantee that we can get 9 00:00:20,000 --> 00:00:21,850 from a standard queue. 10 00:00:21,850 --> 00:00:23,720 So let's take an example of a producer 11 00:00:23,720 --> 00:00:25,920 sending messages into your SQS queue, 12 00:00:25,920 --> 00:00:27,460 the first message, then the second, 13 00:00:27,460 --> 00:00:29,210 the third and the fourth. 14 00:00:29,210 --> 00:00:31,540 And because we have an SQS FIFO queue, 15 00:00:31,540 --> 00:00:33,700 then the consumer will pull the messages 16 00:00:33,700 --> 00:00:36,920 from the SQS FIFO queue and receive the messages 17 00:00:36,920 --> 00:00:39,460 in the exact same order. 18 00:00:39,460 --> 00:00:42,850 Now, because we have such a constraint 19 00:00:42,850 --> 00:00:45,270 and guarantee about ordering, 20 00:00:45,270 --> 00:00:48,540 this SQS queue has limited throughput. 21 00:00:48,540 --> 00:00:52,070 So you get 300 messages per second without batching. 22 00:00:52,070 --> 00:00:54,550 Or if you send batches of messages, 23 00:00:54,550 --> 00:00:59,310 you can get a throughput of up to 3,000 messages per second. 24 00:00:59,310 --> 00:01:00,500 But thanks to FIFO queue, 25 00:01:00,500 --> 00:01:02,370 we get more guarantees and more constraints. 26 00:01:02,370 --> 00:01:05,880 So we have exactly-once send capability 27 00:01:05,880 --> 00:01:08,910 by a feature that allows SQS FIFO queue 28 00:01:08,910 --> 00:01:10,450 to remove duplicates. 29 00:01:10,450 --> 00:01:13,630 And we also know that the messages will be processed 30 00:01:13,630 --> 00:01:15,320 in order by the consumer. 31 00:01:15,320 --> 00:01:17,440 So FIFO queue is something you should see 32 00:01:17,440 --> 00:01:18,810 whenever you have decoupling, 33 00:01:18,810 --> 00:01:22,280 but also the need to maintain the ordering of messages, 34 00:01:22,280 --> 00:01:24,700 and also make sure that you are 35 00:01:24,700 --> 00:01:27,270 on this throughput's constraints 36 00:01:27,270 --> 00:01:31,370 that you are not sending too many messages into SQS, okay? 37 00:01:31,370 --> 00:01:34,290 So let's go ahead and create our first FIFO queue. 38 00:01:34,290 --> 00:01:36,240 So let's go and create a queue 39 00:01:36,240 --> 00:01:38,100 and I will create a FIFO queue. 40 00:01:38,100 --> 00:01:40,570 So as you can see, it's first in first out delivery 41 00:01:40,570 --> 00:01:43,370 and the message ordering is preserved. 42 00:01:43,370 --> 00:01:48,370 Okay, so I will name it demoqueue.fifo 43 00:01:48,400 --> 00:01:51,990 and you have to end it with .fifo. 44 00:01:51,990 --> 00:01:55,190 Otherwise, you will not have the ability 45 00:01:55,190 --> 00:01:56,330 to create this queue. 46 00:01:56,330 --> 00:01:58,460 It has to end with .fifo. 47 00:01:58,460 --> 00:01:59,670 Now, if we look at the configuration, 48 00:01:59,670 --> 00:02:01,510 it looks very similar to before, 49 00:02:01,510 --> 00:02:02,840 but we have one more setting 50 00:02:02,840 --> 00:02:04,700 called content-based deduplication. 51 00:02:04,700 --> 00:02:07,180 This is to deduplicate the messages 52 00:02:07,180 --> 00:02:09,139 if the same is sent twice 53 00:02:09,139 --> 00:02:12,340 in a very small five-minute window. 54 00:02:12,340 --> 00:02:14,270 Access policy will be left the same. 55 00:02:14,270 --> 00:02:16,660 Encryption and so on will be left the same. 56 00:02:16,660 --> 00:02:18,270 So I'll create this queue. 57 00:02:18,270 --> 00:02:22,290 And now if I go to send and receive messages, 58 00:02:22,290 --> 00:02:24,280 we can have a look at the message body. 59 00:02:24,280 --> 00:02:27,870 I can say, Hello World 1. 60 00:02:27,870 --> 00:02:30,920 And then I will have to specify a message group ID. 61 00:02:30,920 --> 00:02:31,880 I'll call this one demo 62 00:02:31,880 --> 00:02:34,270 and we'll use the same message group ID all along this demo. 63 00:02:34,270 --> 00:02:37,740 So demo is sent and a deduplication ID, 64 00:02:37,740 --> 00:02:40,220 excuse me, I will say it's my message number one, 65 00:02:40,220 --> 00:02:41,470 so I'll say ID one. 66 00:02:41,470 --> 00:02:42,630 Send this message. 67 00:02:42,630 --> 00:02:45,420 I'll do Hello World 2, the same message group ID, 68 00:02:45,420 --> 00:02:47,563 and I will say deduplication two. 69 00:02:48,780 --> 00:02:51,630 And then message a third one 70 00:02:51,630 --> 00:02:54,550 and I will say three in here 71 00:02:54,550 --> 00:02:58,500 and finally the fourth one and I will say four. 72 00:02:58,500 --> 00:03:01,100 Okay, so now the messages have been sent 73 00:03:01,100 --> 00:03:02,700 and they're ready to be received. 74 00:03:02,700 --> 00:03:04,510 And so we have four messages available. 75 00:03:04,510 --> 00:03:08,250 And if I pull four messages, we look at all the messages. 76 00:03:08,250 --> 00:03:12,270 And if I look at this one, it's actually in the wrong order. 77 00:03:12,270 --> 00:03:14,390 So if I look at the bottom one, which is the first one, 78 00:03:14,390 --> 00:03:15,880 it says, Hello World 1. 79 00:03:15,880 --> 00:03:19,350 Then if I look at the second message, Hello World 2. 80 00:03:19,350 --> 00:03:22,130 The third message I have Hello World 3. 81 00:03:22,130 --> 00:03:25,120 And the fourth message I will have Hello World 4. 82 00:03:25,120 --> 00:03:28,870 So this is a guarantee that you get thanks to FIFO queues. 83 00:03:28,870 --> 00:03:31,830 Then you go ahead and delete these messages and you're done. 84 00:03:31,830 --> 00:03:32,663 So that's it. 85 00:03:32,663 --> 00:03:33,620 I hope that was helpful. 86 00:03:33,620 --> 00:03:35,570 And I will see you in the next lecture.