Response time

Response time measures the performance of an individual transaction or query. Response time is typically treated as the elapsed time from the moment that a user enters a command or activates a function until the time that the application indicates that the command or function has completed.

The response time for a typical Informix® application includes the following sequence of actions. Each action requires a certain amount of time. The response time does not include the time that it takes for the user to think of and enter a query or request:
  1. The application forwards a query to the database server.
  2. The database server performs query optimization and retrieves any user-defined routines (UDRs). UDRs include both SPL routines and external routines.
  3. The database server retrieves, adds, or updates the appropriate records and performs disk I/O operations directly related to the query.
  4. The database server performs any background I/O operations, such as logging and page cleaning, that occur during the period in which the query or transaction is still pending.
  5. The database server returns a result to the application.
  6. The application displays the information or issues a confirmation and then issues a new prompt to the user.
Figure 1 contains a diagram that shows how the actions just described in steps 1 through 6 contribute to the overall response time.
Figure 1. Components of the response time for a single transaction
Multiple database server processes affect the response time of each transaction.

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