Having completed a thorough review of data requirements and database structure, you are ready to begin loading information into your database. You should start with a small sample, about 500-1000 records, of converted data. Loading a sample lets you check the data mapping and the format and indexing of the data in the IOLS. It is much more efficient to review your decisions with a small amount of information and make changes before the final load because most indexing or data structure changes necessitate a dump and reload of the data. Data loading and review will most likely be an iterative process.
The actual data loading process should be done in steps. Extremely large databases should be loaded incrementally. Problems can be minimized by loading only several thousand records at a time. The amount of time required to load the production system will depend on a variety of factors: