Dynamic Parallel Execution of Oracle Database Parallel Processing Technology

Source: Internet
Author: User

The following articles mainly describe how to share all the relevant content when implementing the Parallel Processing Technology of Oracle Database. If you have doubts about the implementation of the Parallel Processing Technology of Oracle Database, you may wish to browse the following articles and hope that you can get what you want.

Using the Dynamic Parallel Processing Framework of Oracle, you can share all data. The decision to parallelize and divide jobs into smaller units is not limited by any predefined static data distribution made during database setup (Creation.

Because it can construct unrestricted and optimized data subsets for each statement, dynamic parallelism during execution can provide equivalent or even better scalability with a non-shared architecture.

Each query has its own characteristics when accessing, connecting, and processing different parts of data. Therefore, each SQL statement must be optimized and parallelized when parsed. When data is changed, if a more optimized parallel execution plan is available or a node is added to the system, Oracle can automatically adapt to the new situation. This provides the highest degree of flexibility for parallelizing any kind of operations:

(1) Before the statement is executed, the physical data subsets accessed in parallel are dynamically optimized for each query requirement.

(2) The degree of parallelism is optimized for each query. Unlike the non-shared environment, there is no required minimum degree of parallelism to call all nodes to access all data, which is the basic requirement for accessing all data.

(3) operations can run concurrently on one or more Real Application Cluster nodes based on the current workload, features, and query importance.

As long as the statements are optimized and parallelized, you can know all subsequent parallel subtasks. The original process becomes the query Coordinator. The parallel processing server (PX server) is allocated from the public buffer pool of the parallel processing server on one or more nodes and starts to execute this operation in parallel.

Similar to a non-shared architecture, each parallel processing server in the shared architecture works independently on its individual data subset. The transfer mechanism of data or functions between parallel processes is similar or identical to the aforementioned Non-shared architecture. After determining the request's parallel plan, each parallel processing server knows its data set and task, and inter-process communication is as rare as in a non-shared environment.

However, unlike the non-shared architecture, each SQL statement processed in parallel can be optimized without considering any physical database layout restrictions. This allows each parallel processing to construct an optimal data subset, providing better scalability and performance than a purely non-shared architecture. As long as it is beneficial, subsequent steps of parallel operations will be combined and processed by a parallel processing server, thus reducing the need for data transmission or function transmission.

Why Does Oracle Database Parallel Processing Technology share everything better than not?

The non-shared architecture can be traced back to the massive parallel processing (MPP) system as the only hardware architecture that can provide scalable high-end parallel computing. Each node in the MPP System has its own system components (CPU, memory, and disk), which work on different subtasks and cannot share any of its resources.

All of this is over. Currently, most successful and widely used parallel hardware systems are symmetric multi-processor systems (SMP), either stand-alone or as loosely coupled clusters. The SMP system uses a multi-processor that shares public memory and disk resources. Therefore, it is also called a "share everything" system.

Supporters of a purely non-shared architecture always claim that sharing all the architectures (especially the Cluster Environment) lacks scalability for high-end environments and causes significant overhead, therefore, this architecture cannot be used for high-end applications with high concurrency and/or concurrency. This statement is incorrect. Today's hardware and software technologies have solved all the problems in the past, such as high-speed Cluster Interconnection or Oracle Real Application Clusters's high-speed cache fusion architecture.

The Dynamic Parallel Processing Framework of Oracle is based on the same parallel advanced computing design as the non-shared software. It has all the advantages, it also enhances its functions and overcomes the disadvantages of the architecture of non-shared methods. The software based on the principle of non-sharing can be regarded as the first generation but outdated database parallel processing software.

This article introduces the Parallel Processing Technology for Oracle databases. I hope you can learn more about the parallel processing technology for Oracle databases.

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