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This article mainly introduces "parallel parameter analysis in Datapump expdp and impdp". In daily operation, I believe many people have doubts about parallel parameter analysis in Datapump expdp and impdp. The editor consulted all kinds of data and sorted out simple and easy-to-use operation methods. I hope it will be helpful to answer the doubts of "parallel parameter analysis in Datapump expdp and impdp". Next, please follow the editor to study!

In expdp and impdp, you can increase the export import rate through parallelism (the parallel parameter). This parameter is affected by cpu and Iram O. So when using the parallel parameter, there is a tradeoff between resource consumption and elapsed time.

The default value of the Parallel parameter is 1, and when the parallele value is set to 3, it means that there will be up to three threads, not necessarily three threads. Because a dump file has only one thread to process at the same time. So if there is only one output file, then even if parallel=4, there is only one thread working.

1. The parallle parameter filesize in Expdp can be used together.

Parallel: maximum number of threads to execute (parallel read)

Filesize: specify a single file size. Specify the number of files by specifying the size of the file.

An excerpt from official documents: The value you specify for integer should be less than, or equal to, the number of files in the dump file set.

In expdp, the parallel parameter value should be less than or equal to the number of dump files. By default, assuming that parallel=3 is specified on export, three dump files are generated. So when considering the setting of the parallel parameter, you can give priority to how many files need to be exported.

If the prarallel value is set too high, it is possible to report ORA-39095 error.

Eg:$ expdp scott/tiger directroy=dump_dir dumpfile=scott_%U.dmp parallel=4 filesize=10m

2. Parallel parameter in Impdp

The parameters of Parallel in impdp are different from those in expdp.

An excerpt from the official document: If the source of the import is a dump file set consisting of files, then multiple processes can read from the same file, but performance may be limited by I picks O contention.

In impdp, the parallel parameter can be used in one or more files, but the parallel parameter is not as large as possible, which is also limited by Imax O.

Eg:$ impdp scott/tiger directroy=dump_dir dumpfile=scott_%U.dmp parallel=4

At this point, the study of "parallel parameter analysis in Datapump expdp and impdp" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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