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988368 wrote:UNDO will be smaller than the table.
I want to know how much space does the data import occupies on the undotbs tablespace? will it consume the same exact space (size) of the table being imported? I am using impdp for importing data. (data_only).
Also, i want to know when will ORACLE use UNDOTBSalways
and TEMP tbs.Oracle uses TEMP when it needs to; like for BIG sort
IMPDP just does the plain inserts that is what makes datapump platform independant. So if it just doing plain insert , it will definitely use Undo Tablespace. Now the question is how much?
Impdp consume more undo tablespace because it has to run some additional metadata and some master table queries during import.BUt if you are just importing using parameter data_only, you might not go above your table size or might go little above that. For example, if you have 5GB of table, you might go 5.2 GB.
Temporary tablespace: Impdp definitely use Temporay tablespace at lot of places while importing. One is when creating indexes, it has to do a sorting which uses you temporary tablespace.