Responsiveness

Responsiveness of a system is critical to the user experience. Care should be taken to make IFS Applications highly responsive and to make sure the user feels in control.

Guidelines

Try to always put the user in control:

• During time consuming operations, it is important to always use the wait cursor, indicating that some action is being executed. Database calls must always have such an indication.

Make sure operations can be carried out efficiently by programming according to the following guidelines:

• Try to use one select statement/data source where possible. Avoid additional DBPLSQLBlock after populate, which slows down the system.
• Group DB-calls to be one DBPLSQLBlock in the client which calls separate procedures/functions in the server.

  Minimize number of server calls on form load, show context menu, field validation, etc.. Making 10-15 calls in these situations is not acceptable. Group the calls into one, or even better develop a server method that takes needed input parameters, gathers all data needed, and returns that data in a single call (as out parameter, out ref cursor, etc.). The targets for server calls are as follows:
   

  What	Acceptable	Good
  Load form	3 calls	0 calls
  Populate form	2 calls per data source (so for example  master-detail form 4 calls)	1 call per data source (so for example master-detail form 2 calls)
  Show context menu	2 calls	0 calls
  Validate field (tab out)	2 calls	1 call

• Use DBPLSQLBlock if possible instead of DbImmediate due to result in better performance.
• Do not run server calls after row fetch. Instead add additional column to the select statement and retrieve needed data there. Or add in the view definition on the server.
• Use the Debug Console in IFS Enterprise Explorer to track unnecessary DB-calls.
• Avoid large number of columns in windows which slows down Populate/Query commands from the server.
• Don't use static values inside statement, use bind variables instead having the value in each variable changed between the DB-calls. Oracle can then re-use the parsed execution plan for the statement.

  if (DbPLSQLBlock( c_hSql, "&AO.Order_API.Release( 'A1' )"))     // Wrong

  g_Bind.s[0] = "A1";
  if (DbPLSQLBlock( c_hSql, "&AO.Order_API.Release(:g_Bind.s[0] )" ))     // Correct

Note: Read more about "Responsiveness" from a usability perspective on Usability First or Wikipedia.