In order to fulfill the requirement that the system should not be down for more than 10 minutes at any one time, Laser Byte concluded that the only way of doing this was to do the conversions in batches.
Each batch of tables could be converted within 10 minutes and the new front end installed and tested live. Prior testing and small batches meant that each batch was manageable. Each batch was given 2 weeks to settle down before moving on to the next batch.
And Laser Byte were not idle in between batches.... they used this time to write the new front ends for the next batch of tables. They also used the time to do test conversions and also to time them in order to ensure that the downtime of the system was minimised.
Many months and 20 batches later the final batch of tables was completed.
And the task was the largest we have ever undertaken: 480 modules, 137 data tables, 20 million records, a completely new SQL server setup.
The conversion has brought many benefits to the system: the system is faster, more capable of growth, almost limitless in capacity and far more resilient. In fact there have been no database issues since the conversion.
And the conversion brought other, less obvious benefits: Now, Laser Byte Ltd are able to complete modifications and enhancements without taking users out of the system. The searches can be optimised using SQL Native calls and this makes them more versatile.
Overall, it was a total success story!