SQL Loader - Oracle 10g/11g Data and Database Management Utilities - page 53

sqlldr sqlldrdemo/oracle control=pload01.ctl DIRECT=TRUE PARALLEL=TRUE
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sqlldr sqlldrdemo/oracle control=pload02.ctl DIRECT=TRUE PARALLEL=TRUE
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sqlldr sqlldrdemo/oracle control=pload03.ctl DIRECT=TRUE PARALLEL=TRUE
&
sqlldr sqlldrdemo/oracle control=pload04.ctl DIRECT=TRUE PARALLEL=TRUE
&
In this example, four processes execute the data load in parallel. The degree of
parallelism must be tuned, so that the process doesn't end up serializing due to data
file access problems.
When performing a parallel load some issues should be considered:
• Indexes are not maintained and will be marked as UNUSABLE , so the user
must schedule an index maintenance task afterwards.
• The user should look for the constraint status after the load. Both constraints
and triggers must be manually enabled after the load.
General performance booster tips
In order to take advantage of maintenance windows to perform the data load, here is
some advice for improving load performance and better using the time frame.
• When performing a load, do not use logical records, map in one-to-one
physical records to logical records.
• Use LMT with ASSM, this combination is available from Oracle 9i
Rel. 2 onwards.
• Use a ixed size ield data ile format over the variable sized with delimiter
characters.
• Try to avoid character set conversions, try to use the same character set on
the client side and at the server side.
• If possible use direct load; this is the fastest way to load data.
• When loading data try to have the data preordered at the data ile by the
most important index, this way when the index is created the clause NOSORT
can be used. The index will be created faster.
• If possible, use parallel loads, and parallel index maintenance.