Parallel[=(options)] Specifies a parallel load operation. A parallel load operation is especially effective when you have large partitioned tables that do not contain segmented strings and for which no constraints or triggers are defined. If you specify the Parallel qualifier without any options, your load operation is assigned one executor and four communications buffers for that executor. A communications buffer is used for communications between your process and the executors. If you want to assign additional executors or communications buffers, or both, use one or both of the following options: o Buffer_Count=n Allows you to specify the number of communications buffers assigned to each executor in a parallel load operation. Do not confuse this with the Buffers=n qualifier. The Buffers=n qualifier specifies the number of database buffers to use during the load operation. o Executor_Count=n Allows you to specify the number of worker processes to be assigned to the load operation. Ideally, the number of executors should be equal to the number of table partitions. You should not assign a greater number of executors than the number of table partitions. If a table is randomly or vertically partitioned, Oracle RMU creates only one executor, regardless of the number you specify. If the user account's MAXDETACH UAF value is greater than 0, then executors are created as detached processes. If there is no MAXDETACH value set, then executors are created as subprocesses. (A MAXDETACH value = 0 equates to unlimited detached processes.) At the end of each load operation, Oracle RMU displays summary statistics for each executor in the load operation and the main process. Look at the "Idle time" listed in the statistics at the end of the job to detect data skew and look at "Early commits" to detect locking contention. If some executors have a large amount of idle time, you likely have data that is skewed. Ideally, data loaded with the Parallel qualifier should appear in random order within the .unl file. Data that is already in partition order when you attempt to perform a parallel load operation results in high idle time for each executor and thus defeats the advantages of a parallel load operation. The summary statistics also list the number of records read from the input file, the number of data records stored, and the number of data records rejected. In most cases, the number of data records rejected plus the number of data records stored equals the number of data read from the input file. However, under the following circumstances this equation does not hold: o The parallel load operation aborts due to a duplicate record that is not allowed. o You did not specify an exception file. Similarly if a load operation aborts due to a record in the input file being improperly delimited for a delimited text load, the records rejected plus the records stored do not equal the number of records read from the input file. You cannot use a parallel load operation to load list data (segmented string) records or security audit records. If you specify a parallel load operation and attempt to load list data or security audit records, Oracle RMU returns a warning and performs a single-process (non-parallel) load operation.