With an increase in the number of businesses moving to 24-hour online processing, the growing need to modernize applications, and ever-increasing data storage requirements, IBM i developers must plan their application updates to fit into constantly decreasing maintenance windows.
One of the most time-consuming development activities is applying complex structural changes to IBM i database files. Such changes often require database files to be recreated, together with related dependent objects. While small files may take only minutes to process, large database files can take many hours, or even days, to update.
Traditionally, database files are locked during this process and application users cannot access the associated data – or, more often than not, the entire application.
In LMi 8.6 we introduce a new feature to overcome this problem - Convert File While Active (CFWA). CFWA allows users to continue accessing their applications whilst LMi converts application data and recreates dependencies in the background. During background processing, LMi ensures that all database updates are synchronized to ensure the integrity of data is maintained. At a convenient time, an authorized user can instruct LMi to move the new application objects into production - reducing the downtime from hours or days, to just a few minutes.
The following examples were observed by our engineering teams during recent performance testing:
Structural change made: Change to column / field attribute in middle of database file.
Scenario A: Database file with 400 million records, 30 *INDEX, 20 *LF, 50 *VIEW, 2 *ALIAS
Downtime required to process structural changes without CFWA: 1 hour 3 minutes
Downtime required to process structural changes with CFWA: 24 seconds
Downtime saving: 99.4%
Scenario B: Database file with 2 billion records, 30 *INDEX, 20 *LF, 50 *VIEW, 2 *ALIAS
Downtime to process structural changes without CFWA: 9 hours 19 minutes
Downtime to process structural changes with CFWA: 4 minutes
Downtime saving: 99.3%
Scenario C: Database file with 4 billion records, 1 *LF
Downtime to process structural changes without CFWA: 5 hours 46 minutes
Downtime to process structural changes with CFWA: 6 minutes
Downtime saving: 98.3%
Additional examples of time savings observed by our engineering teams during performance testing are detailed in the following graph:
The table above shows the downtime associated with making structural changes to database objects using LMi with and without CFWA enabled. File sizes (both record counts and physical size) are shown together with % downtime saving that CFWA provided during the tests. The column on the right shows that LMi 8.6 removes the previous 2TB file size limit.
If you would like to start using CFWA, please contact our support team who will arrange a complimentary CFWA introduction and familiarization session.
CFWA is included (at no additional cost) in LMi 8.6 and available to all customers with current maintenance agreements. It can be downloaded from the Rocket Community Portal. Reach out to us if we can help you plan your update.
Chris White
Principal Product Manager
Email: cwhite@rocketsoftware.com