I almost ran away

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        In mathematical statistics , There is an important statistical rule ： Suppose an accident is in an experiment （ Activities ） The probability of occurrence in is p（p>0）, It's in n Experiments （ Activities ） The probability of at least one occurrence is P=1-（1-p）n. thus it can be seen , When the number of experiments n Tends to infinity ,pn Will become more and more 1, It becomes an inevitable event

         This conclusion was made by Edward · Murphy should be used in security management , He pointed out that ： Do anything , If there is an objective wrong way , Or there is the possibility of an accident , No matter how unlikely it is , When you do it over and over again , Accidents happen at some point . in other words , As long as the possibility of an accident exists , No matter how small the possibility is , This accident will happen sooner or later （ From Baidu ）

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        Some people say ：“ People need to precipitate , Have enough time to reflect on , To make yourself more perfect ”. As an old bird struggling to fly up , I can feel the importance of precipitation and reflection .

        Think of precipitation and reflection , I just want to record a recent event . It turns out that running is so close to me . In the past, I have read many legends about the running of programmers with multiple versions on the Internet , Most of all rm -rf command . Delete the library and run away , Deleting important documents, running away, etc . I always thought this kind of thing was far away from me , I also only regard it as a self mockery among programmers , Never care . My recent experience has left me in a mess . 

        A few days ago, the provincial network found that there were system vulnerabilities in the system . A month ago, the production environment deployed a patch due to changes in requirements A, Patch A There is an error in the process of ：  When a particular condition is met , When the customer handles the transfer of ownership （ Customer A Users under go to customers B Next operation ） Business time , The user's discount for ordering products is not transferred to the customer together B, As a result, the products of the transfer users can not enjoy preferential treatment , Such users will be stopped in advance . The problem of stopping in advance is more serious , Will cause customer complaints

      Procedural problems need to be solved , Problem customer ordering information needs to be fixed , Customer billing orders also need to be corrected . The boundless things .  Naturally, this task was assigned to me again .

        First , Program issues need to be addressed . Analyze the scene , Make patches , Release patches 、 Online patch 、 Verify that the problem is resolved . Everything went well , Full of confidence .

        Then consider how to correct the problem data . Analyze problem scenarios 、 Statistics confirm the problem data range , Audit problem data , Write repair scripts , Write an audit script to confirm that the problem data has been fixed . Experienced , Full of confidence .

        Because the database is in another province , After sales personnel go out for business , To solve the problem as soon as possible , You can only complete the repair work by yourself . While roast, he handled various applications . Request remote VPN account number , Report changes , Apply for database operation permission . When everything is ready . Remote link to database , Upload the repair script , Follow the processing steps to execute the script .

        Data audit script , adopt . Anticipate ！！

         Statistical data processing , adopt , Same as estimated , A fun ！！

        Fallback problem data , adopt . Like yourself ！！

        Fix the problem data , Prepare to carry out . The company lost power , Change notebook links VPN,VPN The account is abnormal and cannot be logged in . 

    I feel like I'm running away . In the confusion, I thought of Murphy's law

• Nothing is as simple as it seems ;

• Everything will take longer than you expect ;

• Things that go wrong always go wrong ;

• If you're worried about something happening , So it's more likely to happen .

      After half an hour , The power and network have been restored , Handle silently ......

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Some thoughts after the answer to the question

1） Don't think of the problem simply ： Make a backup , Whether it's file backup 、 The backup script , The data backup .

2） I am worried about whether something can happen ： Prepare recovery scripts in advance . When a problem is found, it can be recovered in a short time , Avoid introducing new problems

3） Things that go wrong always go wrong ： SQL The script is marked , such as UPATE Statement processing backs up the modified data to a temporary table or MEM Write a tag in

         

Last one ：Ehcache Configuration data , It is convenient for you to check