Today (06/30/2015) we will have a second more, what can be the consequences for our systems?

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If someone does not know, today 30/06/2015 will have a second more. That is, today after the 23h59m59s we will have 23h59m60s !

This is to do the correction of the International Atomic Time.

I know that there are several services that are synchronized with atomic clocks, such as the one in the National Observatory , which may have problems with this second most.

What kinds of problems can we expect in our systems / servers and applications when such an event occurs?

If you are not aware of anything, check out some stories about it:

Radioagency National - Watches will have an extra second for gravitational changes

Tecmundo - Day 30 of June will have 1 second more, but what can this cause?

    
asked by anonymous 30.06.2015 / 22:07

5 answers

27

Bypassing the problem

Clocks do not usually count the number 60 second, so some alternatives should be taken in this regard. Some possibilities are:

  • Some Linux kernels implement a jump back from 1s, repeating the 59th second. For more information: Resolve Leap Second Issues in Red Hat Enterprise Linux ;
  • Windows servers ignore the second 60, synchronizing again with the atomic clocks just after it passes. This means that they count twice the second 0 on July 1. For more information: How the Windows Time Service treats a leap second ,
  • Some organizations including Amazon Web Services plan to split and spread the second extra for several hours, by making each second a little longer (the English term is "leap smear");
  • If the clock does not connect to a synchronization system, it simply does not implement any kind of tuning for that.

Source: Look Before You Leap - The Coming Leap Second and AWS

Possible Complications

Many technological devices synchronize their clocks with an atomic clock. However, many of them have not been programmed to consider the possibility of the second extra happening, so when the system identifies it it has an unintended result, which can result in crashes of servers and consequently your services.

In 2012, Mozilla, Reddit, Foursquare, Yelp, LinkedIn and StumbleUpon, showed system crashes when the second extra was added. Google, which used the leap smear tactic, escaped unharmed.

This year some servers are expected to experience this problem again.

Source: Daily News - 'Leap second' coming up June 30 may cause computer system problems

Update: What were the damages of the second extra 2015?

Although AWS says it was not the fault of the second extra, its services were down for just over 40 minutes, but not as% of% as of 00:00 UTC to 00:25 , leaving out of the air services like Slack, Netflix, Pinterest and thousands of other websites and services.

The news:

  

Between 5:25 PM and 6:07 PM PDT we have an Internet connectivity issue with a provider outside of our network which affected traffic from some end-user networks. The issue has been resolved and the service is operating normally.

     

The root cause of this issue was an external Internet service provider incorrectly accepting a set of routes for some AWS addresses from a third party who inadvertently advertised these routes. Providers should normally reject these routes by policy, but in this case the routes were accepted and propagated to other ISPs affecting some end-user's ability to access AWS resources. Once we identified the provider and third-party network, we took action to route this incorrect routing configuration. We have worked with this external Internet service provider to ensure that this does not reoccur.

Source: AWS Service Health Dashboard

According to them, it was the fault of external servers who incorrectly accepted a set of routes for some AWS addresses that were inadvertently advertised by third parties ... Was not that clear to you? Not for me either. The fact is that a lot of people are suspicious that the problem was yes of the second extra, although AWS says they do not.

Source: Mashable - Slack, Netflix, Pinterest crash and you can not blame the leap second

    
30.06.2015 / 23:30
7

This question is related to one of the themes from one of SOen's most famous answers,

30.06.2015 / 22:46
4

What will happen is that on the watch it will hold a second during the night.

Note: The information below varies from S.O. and Programming Language.

Tip: Go ahead the clock of your computer, and test the application.

  

Example that will occur at 23h 59m and 59s : 50,51,52,53,54,55,56,57,58, 59 , 59 , 00

This second will be presented twice the impacts to financial systems and using time as a financial basis will be processing the same second " 23:59:59 " twice.

But each application has its function, and the developer should know what behavior your code will display in that situation.

Congratulations on the question!

    
30.06.2015 / 22:20
1

This second can cause a lot of problems in the systems we develop and use, from simple exception to full system removal.

This is because most systems are not prepared to deal with this second more, for those systems the second 60 does not exist.

  

In 2012, for example, the last time an extra second needed to be included in atomic clocks, Mozilla, Reddit, Foursquare, Yelp, LinkedIn, StumbleUpon, Linux operating system, programs developed in Java, for example; failed, and many even went out of thin air.

The reason for this problem is due to problems in the code of the operating systems or the support applications that when they see this additional second arise they freeze due to bugs or programming failure.

So far only google has expressed itself on the case, and claimed that several techniques are being developed to deal with the problem and not affect users.

Sources: Unknown Facts a>, pplware

    
30.06.2015 / 22:22
0

As the link you've been through, the following information is available:

  

Correction of the "Second Interleaved" is determined by the International Service of Reference Systems and Earth Rotation. The last hit happened on December 31, 2012.

     

These one-second adjustments are made since 1972 and from July this year, the difference between the International Atomic Time and Coordinated Universal Time (UTC) will be 36 seconds.

Probably the servers will advance their schedules and even if there was the 23:59:60 time the technologies prevent this, in case the 23:59:60 would probably be converted to 00:00:00 , note also systems in the computer operate in UTC / GMT.

An example with the javascript engine to test: 

var test = document.getElementById("test");

document.getElementById("run").onclick = function() {
    //new Date(anom, mês, dia, horas, minutos, segundos, milisegundos)
    var date = new Date(2015, 05, 30, 23, 59, 60, 0);
    test.innerHTML = date;
};
<div id="test"></div>
<button id="run">Testar</button>
    
30.06.2015 / 22:48
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