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This article introduces the relevant knowledge of "what is the parallelism setting method for Oracle expdp export". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

Today, we tested whether parallelism is added to the export of expdp, and how to add parallelism to maximize the export efficiency. The conclusions are as follows:

Add the parallelism parameter setting when expdp is exported:

Parallel parallelism

Upper limit of filesize individual file size

Total size of the totalsize export file

Meet the following formula to ensure the highest export efficiency:

(parallel-1) * filesize > = totalsize

Here is the data from today's test:

Here is a table of 44.93G. The database server exports 24 CPU,SSD disks normally. The export file size is 38.64G and the export time is 2 minutes and 2 seconds.

Expdp CPIC_PERF/CPIC_PERF directory=IMP_DIR tables= T_CLAIM_PART_TRA_B content=DATA_ONLY dumpfile=T_CLAIM_PART_TRA_B_20190227_PARALLEL.dump

Then we test the export operation with different parallelism:

The first test: executed for 1 minute and 11 seconds, 14 files were exported. It is obvious from the size that the data is mainly saved in the first 7 files, while the amount of data in the last 7 files is smaller because (8-1) * 5cm 35G does not reach the size of the total exported file, so you need to add data files to save the rest of the data, so seven more files have been added.

Expdp CPIC_PERF/CPIC_PERF directory=IMP_DIR tables= T_CLAIM_PART_TRA_B content=DATA_ONLY dumpfile=T_CLAIM_PART_TRA_B_20190227_PARALLEL%U.dump filesize=5G parallel=8

The second test: executed 1 minute 10 seconds, exported 7 files, in fact, 7 files have already met the total file size, so no new data files have been added, although the total time is only 1 second less than the last test, but the number of data files is less than before, which is better.

Expdp CPIC_PERF/CPIC_PERF directory=IMP_DIR tables= T_CLAIM_PART_TRA_B content=DATA_ONLY dumpfile=T_CLAIM_PART_TRA_B_20190227_PARALLEL%U.dump filesize=6G parallel=8

The third test: in view of some claims found on the Internet, we did a test to verify:

The word on the Internet is parallel.

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