The characteristics of distributed databases are: 1. Transparent management of distribution; 2. Transparent management of replicated data; 3. Reliability of transactions; distributed data processing uses a divide-and-conquer approach to solve large-scale data management problems .
Distributed data processing uses a divide and conquer approach to solve large-scale data management problems. The basic characteristics of its data processing are as follows:
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1. Transparent management of distribution
In a distributed system, data is not stored on a site; On multiple sites in a computer network. But logically they are a whole, they are shared by all users and managed uniformly by a DBMS. When users access data, they do not need to indicate where the data is stored, nor do they need to know which server in the distributed system is used to complete it.
2. Transparent management of replicated data
Replication of distributed data helps improve performance and makes it easier to coordinate different and conflicting user needs. At the same time, when a server fails, the data on this server is backed up on other servers, which improves system availability.
This multi-copy method is transparent to users, that is, users do not need to know the existence of copies, and the system manages and coordinates the invocation of copies.
3. Reliability of transactions
Distributed data processing has a repetitive structure, thus eliminating the problem of single point of failure, that is, one or more servers in the system send faults without It will paralyze the entire system, thus improving the reliability of the system.
But in a distributed system, transactions are concurrent, that is, different users may access the same data source at the same time, which requires the system to support distributed concurrency control to ensure the consistency of data in the system.
Distributed systems can solve the storage and access of massive data, but in a distributed environment, the database will encounter more complex problems, for example:
Data in a distributed environment If the data is stored in multiple copies, then how to select a copy when providing data access to users, or how to update every copy in the system if the user modifies the data of a certain copy.
If a server fails due to problems with the network or hardware or software functions while updating information on all copies of the system. In this case, how to ensure that the replica on this server is consistent with other replicas when the failure is restored.
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