Shulou(Shulou.com)11/24 Report--

Recently, there has been news that the balance of customers' deposits in a bank checking account has disappeared. The official response was "technical failure led to the loss of deposit data". Fortunately, the final deposit data recovery was properly resolved!

The man of the document became nervous at first sight of the news. Check your bank card balance. Oh, that's all right!

But when you look at the balance, do you realize that our money has been quantified into data?

Huh? How did our money become data?

A long time ago, people's money was a string of shells, but now, how long has it been since you used cash?

Our wealth is unwittingly turning into a string of numbers. And the increase or decrease of wealth becomes the increase or decrease of numbers.

The question is, will the bank miscalculate the data? Will you lose my data?

The bank database says: don't worry! I got you! It is my important mission to maintain data security.

So, what is a bank database?

To put it simply, the bank database is just like your wife, who specializes in managing money.

In detail, it will care about when, where, how much money you have, and how much money you have left.

However, because it has too many people to manage, banks have strict requirements for the consistency of the database, the performance and the service response ability of the system. A qualified database needs to meet the following points:

1) the accounts cannot be wrong and the data cannot be lost.

Every time you withdraw or remit the amount, you have to make sure that the total amount is correct; similarly, if the data in your account is lost, there is likely to be the problem of deposit loss, so it is a big crime to lose a small target in your account balance.

2) the system cannot be stopped and the online cannot be slow.

Due to the particularity of payment business, the database requires on call 24 hours a day to keep awake, efficient and error-free at all times. You mustn't be sleepy as we are!

3) batch should not be late, and data can be easily migrated.

Due to the huge banking business, many reconciliation operations need to be carried out in batches, and the migration of the database must be easy to implement, otherwise it will affect the opening of the bank the next day.

There are also different types of databases that meet the above requirements. Let's take a look at them together.

Centralized database centralized database stores and processes data centrally in physical space, which is a classical and traditional architecture model.

We can understand that a centralized database is a person with pockets on his body, and all our money is stuffed in different pockets of this person. When we need to withdraw money, this person begins to find the corresponding pocket, count out the banknotes you need and give them to you.

In short, he is responsible for both storing your money and counting your money.

Since it manages all by itself, it is easy to locate which pocket has gone wrong. And because there is no need to coordinate other resources, it can achieve the effect of "waiting for a while".

With the popularity of mobile payment, the number of withdrawals is becoming more and more frequent, and more and more people are withdrawing money.

Once one pocket is broken, it can't take care of the other pockets when it's in a hurry.

So we have a distributed database.

Distributed database is a physically decentralized and logically centralized database system, which provides services through three modules: calculation, storage and management. He owes his origin to the virtualization technology of the server.

Imagine N servers in front of you, and all the hard drives (enclosures) in these servers can be consolidated into a super-large empty house through virtualization technology, and then divide the house into different rooms. used to store the wealth of different users.

It should be noted that the different wealth of the same user can be put in different rooms [private money in one room, ready to hand in money in one room].

So, who will divide the house into new rooms? -- calculation module. He is the owner of the house. In addition to being responsible for the planning of the house space, he also needs to dispatch the remaining resources of different rooms and match the corresponding keys to each room door.

When more people apply for withdrawals, he needs to carefully plan how much money is provided in each room in order to minimize the redundant movement of money.

See here, you will have questions, what if the door lock of which room is broken and can't close the door? Don't worry, we also have a management module.

Like a warehouse keeper, he constantly monitors the security of each room, reinforces the room regularly, and upgrades the accessories in the house. When there is not enough space in the house, he is also responsible for deploying and opening up new rooms and transferring the small money previously placed in the old room without damage.

This division of labor and cooperation constitutes a set of orderly distributed database.

Because the rooms are independent, one room breaks down and the other rooms can continue to be open to us to provide us with payment services. This solves the problem that the centralized database is in a hurry because of a broken pocket.

Of course, the distributed database is far more complex than the document gentleman said.

How does the calculation module calculate? How to exchange information between different rooms? How to manage such a large number of rooms? These are all difficult problems that need to be overcome.

Difficult as the problem is, it cannot stop smart human beings.

Reviewing our knowledge today, it is not difficult to find that centralized databases and distributed databases have their own advantages and disadvantages.

After understanding the database, we hit the workers to continue to work hard to enrich their own small coffers!

This article comes from the official account of Wechat: ZTE documents (ID:ztedoc)

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