MikeMirzayanov's blog

Sad story about rescheduling on the Round 383
By MikeMirzayanov, 8 years ago, translation, In English

Good afternoon.

Sorry. Unfortunately, today (on Friday) we can't run the round 383 :-(

In short, this is because of technical reasons. For those interested in a more detailed description option.

On Thursday night I got sms. It was written that on server for DB backups free HDD space is less than 10%. This server stores three copies of the database over the last three days. It has 2TB drive and Codeforces database over 600GB now.

Since the next day I had planned to spend on the train on the way to NEERC, I decided to delete some redundant data from the DB. I estimate it will give several tens of gigabytes of free space.

I run query to remove redundant data and it was a mistake. I seems because of huge table to update (tens millions of rows) estimated time for the query to compete was at least several hours. As a result, I have killed this query, making KILL QUERY. But the database has continued to lag, I decided to restart it. Operation to shutdown the DB hanged for ~2 hours (I think it was rolling back the transaction), and the DB has stopped to respond and has become quite sad. As a result, I killed the DB process in the operating system and the database already refused to start without a recovery operation, which is also wasn't completed in a couple of hours. In short, I have struggled with this from 5 am to 9 am.

To make Codeforces live I reconfigured it to use database replica in the remote datacenter (in Mail.Ru). Before boarding the train, I started the process of transferring data from the replica back, but contrary to my expectations, this process has been very slow.

It is impossible to run the round using a remote reserve database server. Therefore, we have to move the round forward to Tuesday.

My apologies. I spent many hours struggling with technical issues and worked up to the last. However, it seems the bottleneck is in speed of data transmission over a network, in the speed to write on HDD and in the speed of innobackupex utility.

I hope that on Tuesday everything will go fine!

MikeMirzayanov

Tags 383
  • Vote: I like it
  • +486
  • Vote: I do not like it

Comments Comments (76)
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8 years ago, # |
  Vote: I like it +342 Vote: I do not like it

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8 years ago, # |
  Vote: I like it +20 Vote: I do not like it

i cri

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8 years ago, # |
  Vote: I like it +45 Vote: I do not like it

but, but, I cancel many things to attend :( :( :(

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    8 years ago, # ^ |
      Vote: I like it +184 Vote: I do not like it

    Really sorry about it. Actually I also canceled many things to try to fix and to host the round. I informed all of you as soon as understood that it is impossible to run it. I was pretty sure that it was enough time to repair the DB.

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      8 years ago, # ^ |
        Vote: I like it +58 Vote: I do not like it

      It's absolutely fine. Thanks for the reply tho!

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      8 years ago, # ^ |
        Vote: I like it +13 Vote: I do not like it

      It's really fine, of course a lot of people cancelled plans for the Round but things that happen, you've already done a lot for every one of us and still do with Codeforces. Unfortunate things happen

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      8 years ago, # ^ |
        Vote: I like it +7 Vote: I do not like it

      this is such a great site. we don't mind a few glitches once in a while. Kudos to Codeforces.

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8 years ago, # |
  Vote: I like it +31 Vote: I do not like it

Still much better than a Black day :) Thank you

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    8 years ago, # ^ |
      Vote: I like it +35 Vote: I do not like it

    Oh yes. After Black Day I not only configured backups but also configured monitorings to be sure they really work.

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8 years ago, # |
  Vote: I like it +6 Vote: I do not like it

Mentally prepared myself, had my dinner early and then just opened the browser. The next story is "Sorry, the round 383 has been rescheduled because of technical issues. You can read the details in the post by MikeMirzayanov.!"

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8 years ago, # |
  Vote: I like it +142 Vote: I do not like it

It's very normal for me. I was unlucky everywhere and there isn't any exception.

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    8 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    :D

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    8 years ago, # ^ |
      Vote: I like it +3 Vote: I do not like it

    No it's not true.you are so lucky :)

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      8 years ago, # ^ |
        Vote: I like it -7 Vote: I do not like it

      You don't know what happened for me in INOI or other competitions ... I was very unlucky everywhere ...

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        8 years ago, # ^ |
          Vote: I like it +3 Vote: I do not like it

        I think if you wasn't lucky in one or two situation it doesn't mean that you are an unlucky person and i think that no one is always lucky that's the reason i told you that you are so lucky...

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    8 years ago, # ^ |
      Vote: I like it +16 Vote: I do not like it

    Feel Ya Bro...

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    8 years ago, # ^ |
    ← Rev. 2   Vote: I like it 0 Vote: I do not like it

    Deleted

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    8 years ago, # ^ |
      Vote: I like it +12 Vote: I do not like it

    things happen for you make me cry and there isn't any exception dude!

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      8 years ago, # ^ |
        Vote: I like it +9 Vote: I do not like it

      It is so relaxing that someone cry for you while you even don't know her. Thanks friend.

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    8 years ago, # ^ |
      Vote: I like it +11 Vote: I do not like it

    based on things that I've seen happening to you, I'm sorry to admit that you're really unlucky bro :(

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      8 years ago, # ^ |
        Vote: I like it +2 Vote: I do not like it

      Thanks. I think you saw my "lost love, ruined life" ... for example : 18818737.

      Maybe I need to share my story in my blog, as many peoples wanted that here.

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    8 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    wish you good luck later on man

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8 years ago, # |
  Vote: I like it +20 Vote: I do not like it

It's OK man, you did the best.

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8 years ago, # |
  Vote: I like it +28 Vote: I do not like it

We really appreciate your efforts. We are grateful that at least site is working and we can practice till Tuesday which is nice.

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8 years ago, # |
  Vote: I like it +40 Vote: I do not like it

better than a sudden unrated round :)

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8 years ago, # |
  Vote: I like it -8 Vote: I do not like it

Give me another 2 hour contest to compete in now :(-

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8 years ago, # |
  Vote: I like it +31 Vote: I do not like it

Oh!I can go to see a movie tonight！ Thank you， MikeMirzayanov.

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8 years ago, # |
← Rev. 2   Vote: I like it +10 Vote: I do not like it

The time on Tuesday is very unusual and inconvenient. May be it's better to set usual time 16:35 (UTC)?

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8 years ago, # |
  Vote: I like it 0 Vote: I do not like it

Will you cancel the registrations? I'm not sure whether I have time on Tuesday.

If I had time, I would register again.

Thx

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    8 years ago, # ^ |
    ← Rev. 3   Vote: I like it +21 Vote: I do not like it

    What's the problem to do it by youself? You can do it in the list of registrants

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      8 years ago, # ^ |
      ← Rev. 2   Vote: I like it +5 Vote: I do not like it

      I didn't know it until you told me.

      Brilliant!

      It seems like a secret API to me...

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    8 years ago, # ^ |
      Vote: I like it +21 Vote: I do not like it

    If you don't submit, you won't be rated.

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      8 years ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      is it so? Is that confirmed information because many a times I am very late & busy also but had to hurry just to solve the initial questions.

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        8 years ago, # ^ |
          Vote: I like it +5 Vote: I do not like it

        You can compare the number of registrants and number of rating changes in previous rounds.

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8 years ago, # |
  Vote: I like it +1 Vote: I do not like it

i am very unlucky .. may be i can not participate in that day.. :P

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8 years ago, # |
  Vote: I like it 0 Vote: I do not like it

Are our registrations still active? I can't compete on the new date

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    8 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    You can undo your registration by visiting the page which lists the registered users and clicking x next to your name. Also, if you register but don't submit it counts as if you've never registered.

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8 years ago, # |
  Vote: I like it +19 Vote: I do not like it

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8 years ago, # |
  Vote: I like it -25 Vote: I do not like it

Today is the "BLACK FRIDAY"

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8 years ago, # |
  Vote: I like it +10 Vote: I do not like it

I went out to a cybercafé just to participate in the round -_- ! ):

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8 years ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

My registration is completed.But maybe I have no time four days later.Can I cancel my registration?

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    8 years ago, # ^ |
      Vote: I like it +3 Vote: I do not like it

    You dont need to.. If you dont participate, it wont have any effect on your rating, by the way yes you can cancel your registration ..

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    8 years ago, # ^ |
      Vote: I like it +3 Vote: I do not like it

    You can choose to not participate....that's better than cancelling registration. Apart from that, though, you can, just click the cross mark beside your name in registration list.

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    8 years ago, # ^ |
    ← Rev. 2   Vote: I like it +15 Vote: I do not like it

    yes, you can go to the list of participants, and tap red cross near your name!

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      8 years ago, # ^ |
        Vote: I like it +3 Vote: I do not like it

      I know how to deal with it now.Thanks for your help!

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8 years ago, # |
  Vote: I like it +3 Vote: I do not like it

No problem , Hope you will cope up with this situation quickly like you did in past :) thanks for this excellent OJ .

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8 years ago, # |
  Vote: I like it +3 Vote: I do not like it

NO need to explain mike we are always with you :)

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8 years ago, # |
  Vote: I like it +3 Vote: I do not like it

This Friday was perfect for me and I can't take part on Thursday because I have to be at school at this time :'(

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8 years ago, # |
  Vote: I like it 0 Vote: I do not like it

Thanks for explaining , i thought i missed the round hehe

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8 years ago, # |
  Vote: I like it 0 Vote: I do not like it

we have came a long long way !!

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8 years ago, # |
  Vote: I like it +26 Vote: I do not like it

Well, it isn't that sad as long as all infomrations and DBs are fine now

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8 years ago, # |
  Vote: I like it +4 Vote: I do not like it

Was planning to take my first contest this time. Now I got more time to study I guess.

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8 years ago, # |
  Vote: I like it +3 Vote: I do not like it

That's fine, we appreciate your work. Keep us posted as issues get closed.

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8 years ago, # |
  Vote: I like it +1 Vote: I do not like it

So sad ! I'm being busy that day :((

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8 years ago, # |
  Vote: I like it 0 Vote: I do not like it

I respect you

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8 years ago, # |
  Vote: I like it +18 Vote: I do not like it

I think you should give us a recompense for moral damages and prepare more rated contests on the next week

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8 years ago, # |
  Vote: I like it +14 Vote: I do not like it

No contest? No problem let's enter a virtual one

Btw,We appreciate your efforta

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8 years ago, # |
  Vote: I like it 0 Vote: I do not like it

But, we love CF and we can wait :)

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8 years ago, # |
  Vote: I like it +9 Vote: I do not like it

That was going to be my first contest in really long time (more than 5 months), and the new time is too early for me, I don't think I'll be able to make it. :(

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8 years ago, # |
  Vote: I like it 0 Vote: I do not like it

Oh...that,I saw the news when it is already more than 0:30 here. How terrible the day is...

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8 years ago, # |
← Rev. 3   Vote: I like it +22 Vote: I do not like it

4 extra days of preparation .. (^_^)

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8 years ago, # |
← Rev. 2   Vote: I like it +50 Vote: I do not like it
  • Puts alarm for 10 minutes before the start of contest.
  • I wake up 20 minutes after the scheduled start.
  • Curses myself that missed another contest
  • Reassures that can still participate with a lot of time remaining
  • Logs in to see contest postponed
  • Do not know what to feel now.

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8 years ago, # |
  Vote: I like it 0 Vote: I do not like it

Tell Me

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8 years ago, # |
  Vote: I like it +38 Vote: I do not like it

Is acm.sgu.ru down because of this issue?

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8 years ago, # |
  Vote: I like it +6 Vote: I do not like it

Extra four days! And the round is now on my birthday! How fantastic!

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8 years ago, # |
  Vote: I like it +5 Vote: I do not like it

I was going to cancel plans for a fun trip with friends on Saturday to attend this contest. (I'm in Sydney, so this contest was at 3 AM). But now I consider myself lucky that I decided to "skip" this one contest so I could enjoy with friends :)

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8 years ago, # |
  Vote: I like it +4 Vote: I do not like it

Thanks for eventually fixing the problem and for running CF!

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