DBA Tips Archive for Oracle
Faster database exports/imports
by Jeff Hunter, Sr. Database Administrator
The import and export programs (imp/exp) run in two task mode to protect the SGA from potential corruption by user programs. By relinking these two programs in single task mode you can gain much improvement in speed. In many cases up to 30%. Oracle themselves use this method although it is NOT supported by Oracle.
Running in single-task is much faster but it requires more memory since the Oracle executable's text is no longer shared between the front-end and background processes. If you need to transfer large amounts of data between databases, relink the executale for greater efficiency.
To relink the RDBMS kernel and create the two new imp/exp programs, use the following:
% cd $ORACLE_HOME/rdbms/lib % make -f ins_rdbms.mk singletask % make -f ins_rdbms.mk expst % make -f ins_rdbms.mk impst % make -f ins_rdbms.mk sqlldrst % mv expst $ORACLE_HOME/bin/ % mv impst $ORACLE_HOME/bin/ % mv sqlldrst $ORACLE_HOME/bin/Now use expst and impst instead of imp or exp.
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