Oracle Technical – Improve Import/ Export performance?



Ø       Set the BUFFER parameter to a high value (e.g. 2M)



Ø       Set the RECORDLENGTH parameter to a high value (e.g. 64K)

Ø       Stop unnecessary applications to free-up resources for your job.

Ø       If you run multiple export sessions, ensure they write to different physical disks.

Ø       DO NOT exports to an NFS mount filesystem. It will take forever.



Ø       Create an indexfile so that you can create indexes AFTER you have imported data. Do this by setting INDEXFILE to a filename and then import. No data will be imported but a file containing index definitions will be created. You must edit this file afterwards and supply the passwords for the schemas on all CONNECT statements.

Ø       Place the file to be imported on a separate physical disk from the oracle data files

Ø       Increase DB_CACHE_SIZE (DB_BLOCK_BUFFERS prior to 9i) considerably in the init$SID.ora file

Ø       Set the LOG_BUFFER to a big value and restart oracle.

Ø       Stop redo log archiving if it is running (ALTER DATABASE NOARCHIVELOG)

Ø       Create a BIG tablespace with a BIG rollback segment inside. Set all other rollback segments offline (except the SYSTEM rollback segment of course). The rollback segment must be as big as your biggest table (I think?)

Ø       Use COMMIT=N in the import parameter file if you can afford it

Ø       Use ANALYZE=N in the import parameter file to avoid time consuming ANALYZE statements

Ø       Remember to run the indexfile previously created

 Thanks – Shivmohan Purohit 






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