Shulou(Shulou.com)06/01 Report--

On October 9, 2019, a person from a ministry pointed out at a public meeting that "OceanBase test indicators are high, but they still cannot be used in key areas", "Internet and banking scenarios are completely different", and "batch running (batch processing business) cannot be supported". The essence of the question is "what kind of distributed databases are available in key areas"?

From the user's point of view, the answer is clear, compatible with Oracle functions and meeting performance requirements. Compatible with Oracle, which means "do not transform the seamless upgrade mode of the application system", with low user responsibility and low risk. Meeting the performance requirements means that the business can be run.

Is OceanBase such a product?

Let's start with the compatibility of Oracle:

The core function of database, under the distributed architecture, OceanBase is not compatible with the common database core functions of Oracle, such as stored procedure, trigger, view, multi-table association, large table association and so on. It needs to make up for the functional gap through large-scale transformation of the application system. The project is complicated, and the transformation is not guaranteed to be successful.

Isolation level, OceanBase does not support Oracle isolation level "readable", there is a risk of unknowable data errors and high failure rate

Locking mechanism, compared with Oracle strict locking mechanism, OceanBase is a loose locking mechanism. In financial scenarios with data conflicts, it will inevitably lead to batch (batch processing business) interruption, resulting in the risk of business continuity.

Conclusion: OceanBase is completely incompatible with Oracle, and the gap is due to structural differences, which can not be solved by adaptation.

In addition to performance, the key to distributed database performance is the efficiency of handling distributed transactions:

In both tpc-c tests, the distributed transaction was not completed by the OceanBase database. According to the tpc-c rule, there are random 15% and 1% cross-position transactions. If completely random, 6.896% of the total trading volume, that is, a total of 52.0017798 billion transactions in 8 hours, become distributed transactions across database nodes. Ant Financial Services Group disclosed that "tpmC/ theoretical tpmC=0.987 is tested when OceanBase1557 nodes are clustered". Compared with the stand-alone machine, the performance of the cluster is zero loss, that is, the distributed architecture has no distributed overhead at all. Obviously, the distributed transactions in the tpc-c test are not completed by the OceanBase database nodes.

In June 2019, China Information and Communication Institute and China Software Evaluation Center conducted a public test of distributed database, which did not allow large-scale modification of the application system, and the performance of OceanBase was poor and did not enter the reexamination.

Alipay scene, some professionals believe: "online payment scenario, more connection, and the early settlement of funds in commercial banks, now in the Bank.com platform, rather than the payment company." on the contrary, it shows that the core system of the bank has made great progress. " The payment scenario is obviously different from the financial scenario, and the distributed transaction capability of OceanBase still needs to be proved.

In many external test scenarios of OceanBase, OceanBase has not been seen to complete distributed transactions alone, and it is more shared by the application system, and OceanBase is used as data storage.

Gaussian distributed database belongs to the same category as OceanBase, and its actual combat effect is not good, so it has been removed from the shelves.

Summary, there is no direct evidence for the performance of OceanBase distributed transaction processing.

To sum up, OceanBase is completely incompatible with Oracle, and the performance of distributed database remains to be proved. Structurally, it is more like a database storage than a complete database, like a bare chassis without an engine. Replacing a high-end vehicle Oracle lacks theoretical support and practical proof.

The above ideas can be quickly verified, and a simple Oracle system can be migrated in public, such as a standard OA.

Transferred from: a new generation of distributed database technology (https://mp.weixin.qq.com/s/rRDYNW98DyQhAAb6bSydSw)

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