| This paper is based on the project of data migration in a large scale internet company.During the information technology development, the original information system has been constantly replaced by the new system which has more powerful function.There are many problems about data migration in this processes.In this regard,how to solve data migration becomes the tough task for most entities in the migration.The original system has accumulated plenty of precious data about the corporation ever since it was put into use,and much of them ensures the smooth operation of the new system.Furthermore,these data plays a critical role in the analysis and strategy formulated of the corporation.The essay introduced Oracle and Python related concept, and focus on Oracle Rowid, Data Buffer Cache, and Online Redo Log. With the research result ,a commercial data migration program has been designed according to the features of Python language.The main findings are summarized below :i. Makes a deeply research about the Rowid, from the role of it in data store and reading. Then the influence on speed of migration process was described. A reasonable access policy and design from relevant experiment results show that the correct arrangement rowid would get a good speed.ii. Research on the Data Buffer Cache, from the policy of page in and page out. Also the influence on speed of migration process was described. Experiments indicate a reasonable access method would get a good speed.iii. The information to the end, expounded the online redo log file characteristics and different parameters on how to effect transfer speed. Proposed a set of reciprocal tuning parameters and related experiment.iv. To rowid, data buffers cache and redo log group of research results, using python language to a data transfer procedure. With a large company transfer the project data and carried out experiments, the results indicate that the data removal process is reliable and efficient.The theory and application have reference value on continue in-depth research about data migration. |
