Best practice | database cloud migration solution selection & process analysis


Oracle is a very powerful comprehensive database, but it also has some disadvantages. For example, due to the centralized architecture, it can not achieve horizontal expansion well, and its stability depends on hardware. More and more enterprises need to “go to oracle” for the needs of architecture upgrade, cost reduction and cloud.

A few days ago, alicloud database technology expert fan Wenkai shared the best practices of heterogeneous Oracle database on cloud at the 2019 data technology carnival.

Best practice | database cloud migration solution selection & process analysis

This sharing mainly focuses on the following five aspects:

  1. Overview of Oracle data migration to cloud
  2. Database & Application cloud migration process
  3. Database cloud migration solution
  4. Best practices
  5. Suggestions for enterprise heterogeneous cloud migration

1. Overview of Oracle data migration to cloud

As we all know, Oracle is a very powerful comprehensive database, but Oracle also has some disadvantages. For example, because of the centralized architecture, it can not achieve horizontal expansion well, and its stability depends on hardware, such as IBM minicomputer, EMC storage, etc.

In addition, Oracle database also has technical dependence, many users like to use PL / SQL in the development, so they have to solve the problem of Oracle technology dependence in heterogeneous database upgrade or architecture transformation.

At the same time, the cost of Oracle database is high, and it is difficult to achieve large-scale management with corresponding small computers and storage.

Best practice | database cloud migration solution selection & process analysis

2. Database & Application cloud migration process

Enterprises often need to do “de-o” for the sake of architecture upgrading, cost reduction and cloud computing. The “go o” is generally divided into the following steps.

Best practice | database cloud migration solution selection & process analysis

Step 1: evaluate the migration scheme, analyze how to migrate the database and application, and what database to replace. In this process, we need to reserve a lot of knowledge, analyze the relationship between all the data objects of the existing Oracle database and the application, and judge whether the target database is compatible and whether the migration scheme is feasible.

It is difficult to choose a suitable target database to replace the existing Oracle database, because the performance and load changes can not be determined when replacing Oracle with MySQL and PostgreSQL databases, which can only be completed through continuous testing.

In addition, we need to avoid the risk of heterogeneous migration as far as possible, and we need to ensure that the application and database can adapt well after the migration.

Step 2: database and application transformation. There will be incompatibility in database switching. The incompatibility here will be the “last mile” of database and application architecture transformation. Only when the “last mile” is completed can the whole migration scheme be completed. In this part, we need to consider the transformation scheme of database and application.

Step 3: the cutover of database and application makes full data migration easier, but incremental migration of heterogeneous databases may be more difficult, because it involves a lot of data changes, frequent DDL, and even different data types and precision of databases. These are great challenges for migration.

Finally: database and application migration evaluation, including database escort, because Oracle performance is very strong. Therefore, it is necessary to ensure that after migrating to other databases, the performance can still meet the requirements of the business system.

In the escort phase, we need to consider how to deal with emergencies, how to retreat, and how to switch in the face of complex relationship between database and application.

Comprehensive arrangement of Architecture

For most enterprises, there may be not only one set of Oracle database, nor only one set of applications. There may be various relationships between databases, applications and applications, and between applications and databases. However, enterprises do not have a comprehensive architecture diagram or architecture document to record these contents. Therefore, it is necessary to clarify the relationship between databases and applications for planning Database and application of heterogeneous transformation.

Best practice | database cloud migration solution selection & process analysis

Database scenario carding

In addition, it is necessary to clarify the current business situation of Oracle database, whether it is OLTP, OLAP or the mixed scenario of TP and AP. Only in this way can we select the target database and plan the replacement scheme.

Transformation content

There are many syntactic difficulties in database transformation. First of all, syntax conversion is needed. Because different database engines support different syntax, it is necessary to convert the syntax of DML, DDL and SQL.
Secondly, the application code needs to be converted, because in some cases, SQL statements will be embedded in the program, and it may be necessary to check and modify the SQL statements in millions of lines of code line by line, which is not only a huge workload, but also very time-consuming.

Determine the transformation scheme

After the database and application architecture migration scheme is prepared, the transformation points and function points need to be sorted out and tested one by one, resulting in a long time and a lot of energy for the preparation of the whole process of de-o.

3. Database cloud migration solution

As we all know, Alibaba is the first company in China to practice the idea of going to IOE. In those years, Alibaba’s road to IOE was not so smooth, encountered many difficulties, stepped on many pits, and accumulated a lot of experience, forming the best solution for today’s database cloud migration.

Oracle database and application heterogeneous migration pain points

Best practice | database cloud migration solution selection & process analysis

Full link scheme for heterogeneous cloud migration of Oracle database and Application

Alibaba cloud condenses the experience of database migration process into database and application migration (Adam) products. Adam can help us analyze the architecture of the whole IT system and provide selection suggestions for the target database to be migrated.

At present, Adam products recommend two database cloud migration solutions. The first is OLTP smooth migration solution. The target database is polardb syntax, which is highly compatible with Oracle. Therefore, it can be directly migrated to alicloud or offline polardb box all-in-one machine with only a few changes. The features of the scheme are compatibility, adaptation, flexibility and overall cost.

Best practice | database cloud migration solution selection & process analysis

The second is OLAP data warehouse cloud solution. For Oracle database that provides data warehouse service, it can be migrated to Alibaba cloud’s ADB for PG. The focus of the solution is the transformation of Oracle analytical SQL and the ability to achieve real elastic expansion in the cloud, as well as cost reduction.

Best practice | database cloud migration solution selection & process analysis

Oracle database and application heterogeneous migration is divided into six steps: data acquisition, database intelligent analysis, application evaluation analysis, database and application transformation, project implementation and cutover escort.

Database and application heterogeneous migration full chain solution tool

Adam also provides a full process solution tool for heterogeneous migration of databases and applications. Adam SaaS is the Oracle migration evaluation brain, providing professional, rich and visual database and application evaluation services, static or dynamic interactive reports, application transformation management, and automatic generation of test migration plan.

Adam studio is an Oracle migration and transformation product, which can provide stable and easy-to-use database migration test and transformation tool set, support automatic generation of cutover migration plan, and realize automatic synchronization of simulation and cutover environment plan.
DSG for ADMA is an Adam certified Oracle migration cutover and synchronization product, which can provide a stable and reliable data migration and verification tool set. Taking Adam migration plan as the core, DSG for ADMA provides scenario based, process oriented and automatic data full migration, incremental migration, data verification and data correction capabilities.
Data transmission tool DTS is an alicloud database transmission tool. It also supports data interaction between data sources and can help users achieve full and incremental data migration.

Key technologies of Adam

The core of Adam is intelligent collection, intelligent evaluation, intelligent transformation and supporting tools.
Intelligent collection doesn’t need to collect the contents of database and application program manually. The automatic collection is realized by collecting agent products. After collection, the data will fall to the local, which ensures the data security of core assets.
The intelligent evaluation will compare the performance and syntax of different databases one by one, and recommend the selection of target database, generation of database and application of heterogeneous migration solutions. With the help of supporting tools and intelligent transformation system, the transformation process can be completed quickly, such as shortening the transformation period from 6 months to 1 month.  
According to the database compatibility, Adam divides the difficulty of database object transformation into four levels, and makes different treatments.

In addition, ADMA also provides ADMA studio to realize structure migration and data pre migration. SQL online translation tool can convert Oracle SQL statements into SQL statements of other databases. PL / SQL to Java tool can convert PL / SQL language to Java language. In addition, there are SQL testing tools and Adam certification migration tools.

Best practice | database cloud migration solution selection & process analysis

4. Best practices

Suggestions on database cloud migration selection

According to the number of Oracle features, Oracle database is divided into two categories, weak o feature and strong o feature. For the former, it is recommended to go to the cloud quickly. Because Oracle features are less used, it is quickly migrated to open source database mysql or PostgreSQL to reduce costs.

The latter uses more Oracle features, so polardb Oracle compatible version is recommended. Adam provides a full link migration scheme. If you want to upgrade the overall architecture, you can also directly restructure the business, realize the business microservice division and database sub database and table, and then quickly realize the IT system architecture transformation.

Polardb cloud native distributed relational database architecture is completely autonomous and controllable

Polardb database has many advantages, such as separation of storage and calculation, RPO = 0, automatic read-write separation, data driven, software hardware cooperation, and support of multi-mode data. Polardb is a real cloud native distributed relational database, and its architecture can be completely autonomous and controllable.

Polardb box all in one machine

Some financial enterprises may have higher requirements on database supervision. Therefore, Alibaba cloud also provides polardb box all-in-one machine, which enables enterprises to enjoy the technical dividend of cloud native database in off-line computer rooms. Bring the cloud database to the offline machine room, and make full use of the management and control and performance convenience brought by dbaas.

Best practice | database cloud migration solution selection & process analysis

Analyticdb for PostgreSQL database

For data warehouse scenarios, Alibaba cloud analyticdb for PostgreSQL can well support big data processing and realize real dynamic horizontal expansion.

5. Suggestions for enterprise heterogeneous cloud migration

The cloud migration process of Oracle database needs a complete set of methodology and products to help realize architecture evaluation, database selection, migration evaluation and database application transformation, help realize application decoupling, and also need professional services to help realize real zero downtime migration, and finally realize heterogeneous cloud migration of enterprises.

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Best practice | database cloud migration solution selection & process analysis

Author: roin123

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